From cbbbda456975c5e5e43785b8e9efdcbf8140a456 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Mon, 25 Mar 2019 19:17:09 -0700
Subject: [PATCH 1/5] Unify substitution type `any` handling into costruction
 and instantiation

---
 src/compiler/checker.ts                       | 82 ++++++++--------
 src/compiler/types.ts                         |  6 +-
 .../reference/api/tsserverlibrary.d.ts        |  4 +-
 tests/baselines/reference/api/typescript.d.ts |  4 +-
 ...nalNoInfiniteInstantiationDepth.errors.txt | 97 +++++++++++++++++++
 ...ditionalNoInfiniteInstantiationDepth.types |  2 +-
 ...plifyingConditionalTypesNoCrash.errors.txt | 78 +++++++++++++++
 ...lySimplifyingConditionalTypesNoCrash.types |  2 +-
 .../baselines/reference/conditionalTypes1.js  |  2 -
 .../reference/conditionalTypes1.types         | 14 +--
 .../reference/conditionalTypes2.errors.txt    |  9 +-
 .../reference/conditionalTypes2.types         |  6 +-
 .../reference/infiniteConstraints.errors.txt  | 11 ++-
 ...sCompareCorrectlyInRestrictiveInstances.js | 10 ++
 ...areCorrectlyInRestrictiveInstances.symbols | 36 +++++++
 ...mpareCorrectlyInRestrictiveInstances.types | 20 ++++
 ...sCompareCorrectlyInRestrictiveInstances.ts |  6 ++
 17 files changed, 321 insertions(+), 68 deletions(-)
 create mode 100644 tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt
 create mode 100644 tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt
 create mode 100644 tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.js
 create mode 100644 tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.symbols
 create mode 100644 tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.types
 create mode 100644 tests/cases/compiler/substitutionTypesCompareCorrectlyInRestrictiveInstances.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index aaaacd7100762..2cf6c59a3bc3a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3492,8 +3492,8 @@ namespace ts {
                     context.inferTypeParameters = (<ConditionalType>type).root.inferTypeParameters;
                     const extendsTypeNode = typeToTypeNodeHelper((<ConditionalType>type).extendsType, context);
                     context.inferTypeParameters = saveInferTypeParameters;
-                    const trueTypeNode = typeToTypeNodeHelper(getTrueTypeFromConditionalType(<ConditionalType>type), context);
-                    const falseTypeNode = typeToTypeNodeHelper(getFalseTypeFromConditionalType(<ConditionalType>type), context);
+                    const trueTypeNode = typeToTypeNodeHelper((<ConditionalType>type).resolvedTrueType, context);
+                    const falseTypeNode = typeToTypeNodeHelper((<ConditionalType>type).resolvedFalseType, context);
                     context.approximateLength += 15;
                     return createConditionalTypeNode(checkTypeNode, extendsTypeNode, trueTypeNode, falseTypeNode);
                 }
@@ -7477,6 +7477,10 @@ namespace ts {
         }
 
         function getConstraintOfIndexedAccess(type: IndexedAccessType) {
+            return hasNonCircularBaseConstraint(type) ? getConstraintFromIndexedAccess(type) : undefined;
+        }
+
+        function getConstraintFromIndexedAccess(type: IndexedAccessType) {
             const objectType = getConstraintOfType(type.objectType) || type.objectType;
             if (objectType !== type.objectType) {
                 const constraint = getIndexedAccessType(objectType, type.indexType, /*accessNode*/ undefined, errorType);
@@ -7488,24 +7492,14 @@ namespace ts {
             return baseConstraint && baseConstraint !== type ? baseConstraint : undefined;
         }
 
-        function getDefaultConstraintOfTrueBranchOfConditionalType(root: ConditionalRoot, combinedMapper: TypeMapper | undefined, mapper: TypeMapper | undefined) {
-            const rootTrueType = root.trueType;
-            const rootTrueConstraint = !(rootTrueType.flags & TypeFlags.Substitution)
-                ? rootTrueType
-                : instantiateType(((<SubstitutionType>rootTrueType).substitute), combinedMapper || mapper).flags & TypeFlags.AnyOrUnknown
-                    ? (<SubstitutionType>rootTrueType).typeVariable
-                    : getIntersectionType([(<SubstitutionType>rootTrueType).substitute, (<SubstitutionType>rootTrueType).typeVariable]);
-            return instantiateType(rootTrueConstraint, combinedMapper || mapper);
-        }
-
         function getDefaultConstraintOfConditionalType(type: ConditionalType) {
             if (!type.resolvedDefaultConstraint) {
                 // An `any` branch of a conditional type would normally be viral - specifically, without special handling here,
                 // a conditional type with a single branch of type `any` would be assignable to anything, since it's constraint would simplify to
                 // just `any`. This result is _usually_ unwanted - so instead here we elide an `any` branch from the constraint type,
                 // in effect treating `any` like `never` rather than `unknown` in this location.
-                const trueConstraint = getDefaultConstraintOfTrueBranchOfConditionalType(type.root, type.combinedMapper, type.mapper);
-                const falseConstraint = getFalseTypeFromConditionalType(type);
+                const trueConstraint = getInferredTrueTypeFromConditionalType(type);
+                const falseConstraint = type.resolvedFalseType;
                 type.resolvedDefaultConstraint = isTypeAny(trueConstraint) ? falseConstraint : isTypeAny(falseConstraint) ? trueConstraint : getUnionType([trueConstraint, falseConstraint]);
             }
             return type.resolvedDefaultConstraint;
@@ -7537,10 +7531,14 @@ namespace ts {
             return undefined;
         }
 
-        function getConstraintOfConditionalType(type: ConditionalType) {
+        function getConstraintFromConditionalType(type: ConditionalType) {
             return getConstraintOfDistributiveConditionalType(type) || getDefaultConstraintOfConditionalType(type);
         }
 
+        function getConstraintOfConditionalType(type: ConditionalType) {
+            return hasNonCircularBaseConstraint(type) ? getConstraintFromConditionalType(type) : undefined;
+        }
+
         function getUnionConstraintOfIntersection(type: IntersectionType, targetIsUnion: boolean) {
             let constraints: Type[] | undefined;
             let hasDisjointDomainType = false;
@@ -7617,7 +7615,7 @@ namespace ts {
                     if (!pushTypeResolution(t, TypeSystemPropertyName.ImmediateBaseConstraint)) {
                         return circularConstraintType;
                     }
-                    if (constraintDepth === 50) {
+                    if (constraintDepth >= 50) {
                         // We have reached 50 recursive invocations of getImmediateBaseConstraint and there is a
                         // very high likelyhood we're dealing with an infinite generic type that perpetually generates
                         // new type identities as we descend into it. We stop the recursion here and mark this type
@@ -7684,8 +7682,11 @@ namespace ts {
                     return baseIndexedAccess && baseIndexedAccess !== errorType ? getBaseConstraint(baseIndexedAccess) : undefined;
                 }
                 if (t.flags & TypeFlags.Conditional) {
-                    const constraint = getConstraintOfConditionalType(<ConditionalType>t);
-                    return constraint && getBaseConstraint(constraint);
+                    const constraint = getConstraintFromConditionalType(<ConditionalType>t);
+                    constraintDepth++; // Penalize repeating conditional types (this captures the recursion within getConstraintFromConditionalType and carries it forward)
+                    const result = constraint && getBaseConstraint(constraint);
+                    constraintDepth--;
+                    return result;
                 }
                 if (t.flags & TypeFlags.Substitution) {
                     return getBaseConstraint((<SubstitutionType>t).substitute);
@@ -8866,6 +8867,9 @@ namespace ts {
         }
 
         function getSubstitutionType(typeVariable: TypeVariable, substitute: Type) {
+            if (substitute.flags & TypeFlags.AnyOrUnknown) {
+                return typeVariable;
+            }
             const result = <SubstitutionType>createType(TypeFlags.Substitution);
             result.typeVariable = typeVariable;
             result.substitute = substitute;
@@ -10161,7 +10165,7 @@ namespace ts {
             // Simplifications for types of the form `T extends U ? T : never` and `T extends U ? never : T`.
             if (falseType.flags & TypeFlags.Never && isTypeIdenticalTo(getActualTypeVariable(trueType), getActualTypeVariable(checkType))) {
                 if (checkType.flags & TypeFlags.Any || isTypeAssignableTo(getRestrictiveInstantiation(checkType), getRestrictiveInstantiation(extendsType))) { // Always true
-                    return getDefaultConstraintOfTrueBranchOfConditionalType(root, /*combinedMapper*/ undefined, mapper);
+                    return trueType;
                 }
                 else if (isIntersectionEmpty(checkType, extendsType)) { // Always false
                     return neverType;
@@ -10172,7 +10176,7 @@ namespace ts {
                     return neverType;
                 }
                 else if (checkType.flags & TypeFlags.Any || isIntersectionEmpty(checkType, extendsType)) { // Always false
-                    return falseType; // TODO: Intersect negated `extends` type here
+                    return falseType;
                 }
             }
 
@@ -10227,21 +10231,15 @@ namespace ts {
             result.extendsType = extendsType;
             result.mapper = mapper;
             result.combinedMapper = combinedMapper;
-            if (!combinedMapper) {
-                result.resolvedTrueType = trueType;
-                result.resolvedFalseType = falseType;
-            }
+            result.resolvedTrueType = trueType;
+            result.resolvedFalseType = falseType;
             result.aliasSymbol = root.aliasSymbol;
             result.aliasTypeArguments = instantiateTypes(root.aliasTypeArguments, mapper!); // TODO: GH#18217
             return result;
         }
 
-        function getTrueTypeFromConditionalType(type: ConditionalType) {
-            return type.resolvedTrueType || (type.resolvedTrueType = instantiateType(type.root.trueType, type.mapper));
-        }
-
-        function getFalseTypeFromConditionalType(type: ConditionalType) {
-            return type.resolvedFalseType || (type.resolvedFalseType = instantiateType(type.root.falseType, type.mapper));
+        function getInferredTrueTypeFromConditionalType(type: ConditionalType) {
+            return type.inferredTrueType || (type.inferredTrueType = instantiateType(type.root.trueType, type.combinedMapper || type.mapper));
         }
 
         function getInferTypeParameters(node: ConditionalTypeNode): TypeParameter[] | undefined {
@@ -11182,7 +11180,11 @@ namespace ts {
                     return getSubstitutionType(maybeVariable as TypeVariable, instantiateType((<SubstitutionType>type).substitute, mapper));
                 }
                 else {
-                    return maybeVariable;
+                    const sub = instantiateType((<SubstitutionType>type).substitute, mapper);
+                    if (sub.flags & TypeFlags.AnyOrUnknown || isTypeSubtypeOf(maybeVariable, sub)) {
+                        return maybeVariable;
+                    }
+                    return sub;
                 }
             }
             return type;
@@ -12706,8 +12708,8 @@ namespace ts {
                         if ((<ConditionalType>source).root.isDistributive === (<ConditionalType>target).root.isDistributive) {
                             if (result = isRelatedTo((<ConditionalType>source).checkType, (<ConditionalType>target).checkType, /*reportErrors*/ false)) {
                                 if (result &= isRelatedTo((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType, /*reportErrors*/ false)) {
-                                    if (result &= isRelatedTo(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target), /*reportErrors*/ false)) {
-                                        if (result &= isRelatedTo(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target), /*reportErrors*/ false)) {
+                                    if (result &= isRelatedTo((<ConditionalType>source).resolvedTrueType, (<ConditionalType>target).resolvedTrueType, /*reportErrors*/ false)) {
+                                        if (result &= isRelatedTo((<ConditionalType>source).resolvedFalseType, (<ConditionalType>target).resolvedFalseType, /*reportErrors*/ false)) {
                                             return result;
                                         }
                                     }
@@ -12828,7 +12830,7 @@ namespace ts {
                             return result;
                         }
                     }
-                    const constraint = getConstraintOfType(<TypeParameter>source);
+                    const constraint = getConstraintOfType(<TypeVariable>source);
                     if (!constraint || (source.flags & TypeFlags.TypeParameter && constraint.flags & TypeFlags.Any)) {
                         // A type variable with no constraint is not related to the non-primitive object type.
                         if (result = isRelatedTo(emptyObjectType, extractTypesOfKind(target, ~TypeFlags.NonPrimitive))) {
@@ -12860,8 +12862,8 @@ namespace ts {
                         // and Y1 is related to Y2.
                         if (isTypeIdenticalTo((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType) &&
                             (isRelatedTo((<ConditionalType>source).checkType, (<ConditionalType>target).checkType) || isRelatedTo((<ConditionalType>target).checkType, (<ConditionalType>source).checkType))) {
-                            if (result = isRelatedTo(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target), reportErrors)) {
-                                result &= isRelatedTo(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target), reportErrors);
+                            if (result = isRelatedTo((<ConditionalType>source).resolvedTrueType, (<ConditionalType>target).resolvedTrueType, reportErrors)) {
+                                result &= isRelatedTo((<ConditionalType>source).resolvedFalseType, (<ConditionalType>target).resolvedFalseType, reportErrors);
                             }
                             if (result) {
                                 errorInfo = saveErrorInfo;
@@ -14696,12 +14698,12 @@ namespace ts {
                 else if (source.flags & TypeFlags.Conditional && target.flags & TypeFlags.Conditional) {
                     inferFromTypes((<ConditionalType>source).checkType, (<ConditionalType>target).checkType);
                     inferFromTypes((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType);
-                    inferFromTypes(getTrueTypeFromConditionalType(<ConditionalType>source), getTrueTypeFromConditionalType(<ConditionalType>target));
-                    inferFromTypes(getFalseTypeFromConditionalType(<ConditionalType>source), getFalseTypeFromConditionalType(<ConditionalType>target));
+                    inferFromTypes((<ConditionalType>source).resolvedTrueType, (<ConditionalType>target).resolvedTrueType);
+                    inferFromTypes((<ConditionalType>source).resolvedFalseType, (<ConditionalType>target).resolvedFalseType);
                 }
                 else if (target.flags & TypeFlags.Conditional && !contravariant) {
-                    inferFromTypes(source, getTrueTypeFromConditionalType(<ConditionalType>target));
-                    inferFromTypes(source, getFalseTypeFromConditionalType(<ConditionalType>target));
+                    inferFromTypes(source, (<ConditionalType>target).resolvedTrueType);
+                    inferFromTypes(source, (<ConditionalType>target).resolvedFalseType);
                 }
                 else if (target.flags & TypeFlags.UnionOrIntersection) {
                     for (const t of (<UnionOrIntersectionType>target).types) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index bc12adf004fb1..c98bf55013616 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -4310,8 +4310,10 @@ namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType?: Type;
-        resolvedFalseType?: Type;
+        resolvedTrueType: Type;
+        resolvedFalseType: Type;
+        /* @internal */
+        inferredTrueType?: Type; // The `trueType` instantiated with the `combinedMapper`, if present
         /* @internal */
         resolvedDefaultConstraint?: Type;
         /* @internal */
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index 59ae825a8dc80..a84867f52fd38 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -2382,8 +2382,8 @@ declare namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType?: Type;
-        resolvedFalseType?: Type;
+        resolvedTrueType: Type;
+        resolvedFalseType: Type;
     }
     interface SubstitutionType extends InstantiableType {
         typeVariable: TypeVariable;
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index 2b8056735a476..bec7f9faf9f45 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -2382,8 +2382,8 @@ declare namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType?: Type;
-        resolvedFalseType?: Type;
+        resolvedTrueType: Type;
+        resolvedFalseType: Type;
     }
     interface SubstitutionType extends InstantiableType {
         typeVariable: TypeVariable;
diff --git a/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt b/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt
new file mode 100644
index 0000000000000..8ae6eb886fdd4
--- /dev/null
+++ b/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt
@@ -0,0 +1,97 @@
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(33,13): error TS2456: Type alias 'Shared' circularly references itself.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(35,35): error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(35,35): error TS2315: Type 'Shared' is not generic.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,15): error TS2313: Type parameter 'P' has a circular constraint.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,76): error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,101): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,128): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(63,55): error TS2344: Type 'string | number | symbol' does not satisfy the constraint 'keyof GetProps<C>'.
+  Type 'string' is not assignable to type 'keyof GetProps<C>'.
+tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(63,61): error TS2315: Type 'Shared' is not generic.
+
+
+==== tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts (9 errors) ====
+    declare class Component<P> {
+        constructor(props: Readonly<P>);
+        constructor(props: P, context?: any);
+        readonly props: Readonly<P> & Readonly<{ children?: {} }>;
+    }
+    interface ComponentClass<P = {}> {
+        new (props: P, context?: any): Component<P>;
+        propTypes?: WeakValidationMap<P>;
+        defaultProps?: Partial<P>;
+        displayName?: string;
+    }
+    interface FunctionComponent<P = {}> {
+        (props: P & { children?: {} }, context?: any): {} | null;
+        propTypes?: WeakValidationMap<P>;
+        defaultProps?: Partial<P>;
+        displayName?: string;
+    }
+    
+    export declare const nominalTypeHack: unique symbol;
+    export interface Validator<T> {
+        (props: object, propName: string, componentName: string, location: string, propFullName: string): Error | null;
+        [nominalTypeHack]?: T;
+    }
+    type WeakValidationMap<T> = {
+        [K in keyof T]?: null extends T[K]
+            ? Validator<T[K] | null | undefined>
+            : undefined extends T[K]
+            ? Validator<T[K] | null | undefined>
+            : Validator<T[K]>
+    };
+    type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
+    
+    export type Shared<
+                ~~~~~~
+!!! error TS2456: Type alias 'Shared' circularly references itself.
+        InjectedProps,
+        DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
+                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
+                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'Shared' is not generic.
+        > = {
+            [P in Extract<keyof InjectedProps, keyof DecorationTargetProps>]?: InjectedProps[P] extends DecorationTargetProps[P] ? DecorationTargetProps[P] : never;
+                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2313: Type parameter 'P' has a circular constraint.
+!!! related TS2751 tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts:35:35: Circularity originates in type at this location.
+                                                                               ~~~~~~~~~~~~~~~~
+!!! error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
+                                                                                                        ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+                                                                                                                                   ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+        };
+    
+    // Infers prop type from component C
+    export type GetProps<C> = C extends ComponentType<infer P> ? P : never;
+    
+    export type ConnectedComponentClass<
+        C extends ComponentType<any>,
+        P
+    > = ComponentClass<P> & {
+        WrappedComponent: C;
+    };
+    
+    export type Matching<InjectedProps, DecorationTargetProps> = {
+        [P in keyof DecorationTargetProps]: P extends keyof InjectedProps
+            ? InjectedProps[P] extends DecorationTargetProps[P]
+                ? DecorationTargetProps[P]
+                : InjectedProps[P]
+            : DecorationTargetProps[P];
+    };
+    
+    export type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
+    
+    export type InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> =
+        <C extends ComponentType<Matching<TInjectedProps, GetProps<C>>>>(
+            component: C
+        ) => ConnectedComponentClass<C, Omit<GetProps<C>, keyof Shared<TInjectedProps, GetProps<C>>> & TNeedsProps>;
+                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2344: Type 'string | number | symbol' does not satisfy the constraint 'keyof GetProps<C>'.
+!!! error TS2344:   Type 'string' is not assignable to type 'keyof GetProps<C>'.
+                                                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'Shared' is not generic.
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types b/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types
index 5bef1baa732a8..357f9195f3572 100644
--- a/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types
+++ b/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types
@@ -79,7 +79,7 @@ type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
 >ComponentType : ComponentType<P>
 
 export type Shared<
->Shared : Shared<InjectedProps, DecorationTargetProps>
+>Shared : any
 
     InjectedProps,
     DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
diff --git a/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt b/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt
new file mode 100644
index 0000000000000..ef22bdb6f2faf
--- /dev/null
+++ b/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt
@@ -0,0 +1,78 @@
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(3,6): error TS2456: Type alias 'Shared' circularly references itself.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(5,35): error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(5,35): error TS2315: Type 'Shared' is not generic.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,15): error TS2313: Type parameter 'P' has a circular constraint.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,75): error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,100): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,127): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(15,16): error TS2315: Type 'Shared' is not generic.
+tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(17,37): error TS2315: Type 'Shared' is not generic.
+
+
+==== tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts (9 errors) ====
+    type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
+    
+    type Shared< // Circularly self constraining type, defered thanks to mapping
+         ~~~~~~
+!!! error TS2456: Type alias 'Shared' circularly references itself.
+        InjectedProps,
+        DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
+                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
+                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'Shared' is not generic.
+        > = {
+            [P in Extract<keyof InjectedProps, keyof DecorationTargetProps>]: InjectedProps[P] extends DecorationTargetProps[P] ? DecorationTargetProps[P] : never;
+                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2313: Type parameter 'P' has a circular constraint.
+!!! related TS2751 tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts:5:35: Circularity originates in type at this location.
+                                                                              ~~~~~~~~~~~~~~~~
+!!! error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
+                                                                                                       ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+                                                                                                                                  ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
+        };
+    
+    interface ComponentClass<P> {
+        defaultProps?: Partial<P>; // Inference target is also mapped _and_ optional
+    }
+    
+    interface InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> {
+        <P extends Shared<TInjectedProps, P>>(
+                   ~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'Shared' is not generic.
+            component: ComponentClass<P>
+        ): ComponentClass<Omit<P, keyof Shared<TInjectedProps, P>> & TNeedsProps> & { WrappedComponent: ComponentClass<P> }
+                                        ~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2315: Type 'Shared' is not generic.
+    } // Then intersected with and indexed via Omit and &
+    
+    interface Connect { // Then strictly compared with another signature in its context
+        <TStateProps, TOwnProps>(
+            mapStateToProps: unknown,
+        ): InferableComponentEnhancerWithProps<TStateProps, TOwnProps>;
+    
+        <TDispatchProps, TOwnProps>(
+            mapStateToProps: null | undefined,
+            mapDispatchToProps: unknown,
+            mergeProps: null | undefined,
+            options: unknown
+        ): InferableComponentEnhancerWithProps<TDispatchProps, TOwnProps>;
+    }
+    
+    declare var connect: Connect;
+    
+    const myStoreConnect: Connect = function(
+        mapStateToProps?: any,
+        mapDispatchToProps?: any,
+        mergeProps?: any,
+        options: unknown = {},
+    ) {
+        return connect(
+            mapStateToProps,
+            mapDispatchToProps,
+            mergeProps,
+            options,
+        );
+    };
\ No newline at end of file
diff --git a/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types b/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types
index 4a3a1fdbe53aa..74bdbec990ad4 100644
--- a/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types
+++ b/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types
@@ -3,7 +3,7 @@ type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
 >Omit : Pick<T, Exclude<keyof T, K>>
 
 type Shared< // Circularly self constraining type, defered thanks to mapping
->Shared : Shared<InjectedProps, DecorationTargetProps>
+>Shared : any
 
     InjectedProps,
     DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
diff --git a/tests/baselines/reference/conditionalTypes1.js b/tests/baselines/reference/conditionalTypes1.js
index b592bd33d10e8..5dc4851838467 100644
--- a/tests/baselines/reference/conditionalTypes1.js
+++ b/tests/baselines/reference/conditionalTypes1.js
@@ -509,8 +509,6 @@ declare function f5<T extends Options, K extends string>(p: K): Extract<T, {
 }>;
 declare let x0: {
     k: "a";
-} & {
-    k: "a";
     a: number;
 };
 declare type OptionsOfKind<K extends Options["k"]> = Extract<Options, {
diff --git a/tests/baselines/reference/conditionalTypes1.types b/tests/baselines/reference/conditionalTypes1.types
index 8cca94f0a1021..125324d60d44a 100644
--- a/tests/baselines/reference/conditionalTypes1.types
+++ b/tests/baselines/reference/conditionalTypes1.types
@@ -9,7 +9,7 @@ type T02 = Exclude<string | number | (() => void), Function>;  // string | numbe
 >T02 : string | number
 
 type T03 = Extract<string | number | (() => void), Function>;  // () => void
->T03 : Function & (() => void)
+>T03 : () => void
 
 type T04 = NonNullable<string | number | undefined>;  // string | number
 >T04 : string | number
@@ -113,7 +113,7 @@ type T10 = Exclude<Options, { k: "a" | "b" }>;  // { k: "c", c: boolean }
 >k : "a" | "b"
 
 type T11 = Extract<Options, { k: "a" | "b" }>;  // { k: "a", a: number } | { k: "b", b: string }
->T11 : ({ k: "a" | "b"; } & { k: "a"; a: number; }) | ({ k: "a" | "b"; } & { k: "b"; b: string; })
+>T11 : { k: "a"; a: number; } | { k: "b"; b: string; }
 >k : "a" | "b"
 
 type T12 = Exclude<Options, { k: "a" } | { k: "b" }>;  // { k: "c", c: boolean }
@@ -122,7 +122,7 @@ type T12 = Exclude<Options, { k: "a" } | { k: "b" }>;  // { k: "c", c: boolean }
 >k : "b"
 
 type T13 = Extract<Options, { k: "a" } | { k: "b" }>;  // { k: "a", a: number } | { k: "b", b: string }
->T13 : ({ k: "a"; } & { k: "a"; a: number; }) | ({ k: "b"; } & { k: "a"; a: number; }) | ({ k: "a"; } & { k: "b"; b: string; }) | ({ k: "b"; } & { k: "b"; b: string; })
+>T13 : { k: "a"; a: number; } | { k: "b"; b: string; }
 >k : "a"
 >k : "b"
 
@@ -140,8 +140,8 @@ declare function f5<T extends Options, K extends string>(p: K): Extract<T, { k:
 >k : K
 
 let x0 = f5("a");  // { k: "a", a: number }
->x0 : { k: "a"; } & { k: "a"; a: number; }
->f5("a") : { k: "a"; } & { k: "a"; a: number; }
+>x0 : { k: "a"; a: number; }
+>f5("a") : { k: "a"; a: number; }
 >f5 : <T extends Options, K extends string>(p: K) => Extract<T, { k: K; }>
 >"a" : "a"
 
@@ -150,13 +150,13 @@ type OptionsOfKind<K extends Options["k"]> = Extract<Options, { k: K }>;
 >k : K
 
 type T16 = OptionsOfKind<"a" | "b">;  // { k: "a", a: number } | { k: "b", b: string }
->T16 : ({ k: "a" | "b"; } & { k: "a"; a: number; }) | ({ k: "a" | "b"; } & { k: "b"; b: string; })
+>T16 : { k: "a"; a: number; } | { k: "b"; b: string; }
 
 type Select<T, K extends keyof T, V extends T[K]> = Extract<T, { [P in K]: V }>;
 >Select : Extract<T, { [P in K]: V; }>
 
 type T17 = Select<Options, "k", "a" | "b">;  // // { k: "a", a: number } | { k: "b", b: string }
->T17 : ({ k: "a" | "b"; } & { k: "a"; a: number; }) | ({ k: "a" | "b"; } & { k: "b"; b: string; })
+>T17 : { k: "a"; a: number; } | { k: "b"; b: string; }
 
 type TypeName<T> =
 >TypeName : TypeName<T>
diff --git a/tests/baselines/reference/conditionalTypes2.errors.txt b/tests/baselines/reference/conditionalTypes2.errors.txt
index 6cf81cf573039..ee7c10ada5891 100644
--- a/tests/baselines/reference/conditionalTypes2.errors.txt
+++ b/tests/baselines/reference/conditionalTypes2.errors.txt
@@ -21,13 +21,13 @@ tests/cases/conformance/types/conditional/conditionalTypes2.ts(25,5): error TS23
       Type 'A' is not assignable to type 'B'.
 tests/cases/conformance/types/conditional/conditionalTypes2.ts(73,12): error TS2345: Argument of type 'Extract<Extract<T, Foo>, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
   Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
-    Type 'Extract<Foo & T, Bar>' is not assignable to type '{ foo: string; bat: string; }'.
+    Type 'Extract<T, Bar>' is not assignable to type '{ foo: string; bat: string; }'.
       Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
 tests/cases/conformance/types/conditional/conditionalTypes2.ts(74,12): error TS2345: Argument of type 'Extract<T, Foo & Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
   Property 'bat' is missing in type 'Foo & Bar' but required in type '{ foo: string; bat: string; }'.
 tests/cases/conformance/types/conditional/conditionalTypes2.ts(75,12): error TS2345: Argument of type 'Extract2<T, Foo, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
   Type 'T extends Bar ? T : never' is not assignable to type '{ foo: string; bat: string; }'.
-    Type 'Bar & Foo & T' is not assignable to type '{ foo: string; bat: string; }'.
+    Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
 
 
 ==== tests/cases/conformance/types/conditional/conditionalTypes2.ts (7 errors) ====
@@ -132,7 +132,7 @@ tests/cases/conformance/types/conditional/conditionalTypes2.ts(75,12): error TS2
                ~
 !!! error TS2345: Argument of type 'Extract<Extract<T, Foo>, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
 !!! error TS2345:   Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
-!!! error TS2345:     Type 'Extract<Foo & T, Bar>' is not assignable to type '{ foo: string; bat: string; }'.
+!!! error TS2345:     Type 'Extract<T, Bar>' is not assignable to type '{ foo: string; bat: string; }'.
 !!! error TS2345:       Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
 !!! related TS2728 tests/cases/conformance/types/conditional/conditionalTypes2.ts:62:43: 'bat' is declared here.
 !!! related TS2728 tests/cases/conformance/types/conditional/conditionalTypes2.ts:62:43: 'bat' is declared here.
@@ -145,7 +145,8 @@ tests/cases/conformance/types/conditional/conditionalTypes2.ts(75,12): error TS2
                ~
 !!! error TS2345: Argument of type 'Extract2<T, Foo, Bar>' is not assignable to parameter of type '{ foo: string; bat: string; }'.
 !!! error TS2345:   Type 'T extends Bar ? T : never' is not assignable to type '{ foo: string; bat: string; }'.
-!!! error TS2345:     Type 'Bar & Foo & T' is not assignable to type '{ foo: string; bat: string; }'.
+!!! error TS2345:     Property 'bat' is missing in type 'Bar & Foo' but required in type '{ foo: string; bat: string; }'.
+!!! related TS2728 tests/cases/conformance/types/conditional/conditionalTypes2.ts:62:43: 'bat' is declared here.
     }
     
     // Repros from #22860
diff --git a/tests/baselines/reference/conditionalTypes2.types b/tests/baselines/reference/conditionalTypes2.types
index 7113ccc2be809..aac6ba47475c6 100644
--- a/tests/baselines/reference/conditionalTypes2.types
+++ b/tests/baselines/reference/conditionalTypes2.types
@@ -130,14 +130,14 @@ function f12(x: string | (() => string) | undefined) {
 >x : string | (() => string) | undefined
 
     const f = getFunction(x);  // () => string
->f : Function & (() => string)
->getFunction(x) : Function & (() => string)
+>f : () => string
+>getFunction(x) : () => string
 >getFunction : <T>(item: T) => Extract<T, Function>
 >x : string | (() => string) | undefined
 
     f();
 >f() : string
->f : Function & (() => string)
+>f : () => string
 }
 
 type Foo = { foo: string };
diff --git a/tests/baselines/reference/infiniteConstraints.errors.txt b/tests/baselines/reference/infiniteConstraints.errors.txt
index a31bf10adb192..414fa8f9213a4 100644
--- a/tests/baselines/reference/infiniteConstraints.errors.txt
+++ b/tests/baselines/reference/infiniteConstraints.errors.txt
@@ -1,12 +1,13 @@
 tests/cases/compiler/infiniteConstraints.ts(3,37): error TS2589: Type instantiation is excessively deep and possibly infinite.
 tests/cases/compiler/infiniteConstraints.ts(4,37): error TS2536: Type '"val"' cannot be used to index type 'B[Exclude<keyof B, K>]'.
+tests/cases/compiler/infiniteConstraints.ts(21,21): error TS2536: Type '"val"' cannot be used to index type 'Extract<T[K], Record<"val", string>>'.
+tests/cases/compiler/infiniteConstraints.ts(21,57): error TS2536: Type '"val"' cannot be used to index type 'Extract<T[Exclude<keyof T, K>], Record<"val", string>>'.
 tests/cases/compiler/infiniteConstraints.ts(31,43): error TS2322: Type 'Record<"val", "dup">' is not assignable to type 'never'.
 tests/cases/compiler/infiniteConstraints.ts(31,63): error TS2322: Type 'Record<"val", "dup">' is not assignable to type 'never'.
 tests/cases/compiler/infiniteConstraints.ts(36,71): error TS2536: Type '"foo"' cannot be used to index type 'T[keyof T]'.
-tests/cases/compiler/infiniteConstraints.ts(36,71): error TS2589: Type instantiation is excessively deep and possibly infinite.
 
 
-==== tests/cases/compiler/infiniteConstraints.ts (6 errors) ====
+==== tests/cases/compiler/infiniteConstraints.ts (7 errors) ====
     // Both of the following types trigger the recursion limiter in getImmediateBaseConstraint
     
     type T1<B extends { [K in keyof B]: Extract<B[Exclude<keyof B, K>], { val: string }>["val"] }> = B;
@@ -32,6 +33,10 @@ tests/cases/compiler/infiniteConstraints.ts(36,71): error TS2589: Type instantia
     declare function ensureNoDuplicates<
       T extends {
         [K in keyof T]: Extract<T[K], Value>["val"] extends Extract<T[Exclude<keyof T, K>], Value>["val"]
+                        ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2536: Type '"val"' cannot be used to index type 'Extract<T[K], Record<"val", string>>'.
+                                                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS2536: Type '"val"' cannot be used to index type 'Extract<T[Exclude<keyof T, K>], Record<"val", string>>'.
           ? never
           : any
       }
@@ -55,6 +60,4 @@ tests/cases/compiler/infiniteConstraints.ts(36,71): error TS2589: Type instantia
     declare function function1<T extends {[K in keyof T]: Cond<T[K]>}>(): T[keyof T]["foo"];
                                                                           ~~~~~~~~~~~~~~~~~
 !!! error TS2536: Type '"foo"' cannot be used to index type 'T[keyof T]'.
-                                                                          ~~~~~~~~~~~~~~~~~
-!!! error TS2589: Type instantiation is excessively deep and possibly infinite.
     
\ No newline at end of file
diff --git a/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.js b/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.js
new file mode 100644
index 0000000000000..c4bb71f2818b5
--- /dev/null
+++ b/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.js
@@ -0,0 +1,10 @@
+//// [substitutionTypesCompareCorrectlyInRestrictiveInstances.ts]
+type UnionKeys<T> = T extends any ? keyof T : never;
+type BugHelper<T, TAll> = T extends any ? Exclude<UnionKeys<TAll>, keyof T> : never
+type Bug<TAll> =  BugHelper<TAll, TAll>
+type Q = UnionKeys<{ a : any } | { b: any }>    // should be "a" | "b"
+type R = Bug<{ a : any } | { b: any }>          // should be "a" | "b"
+
+
+//// [substitutionTypesCompareCorrectlyInRestrictiveInstances.js]
+"use strict";
diff --git a/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.symbols b/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.symbols
new file mode 100644
index 0000000000000..31f23823705d6
--- /dev/null
+++ b/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.symbols
@@ -0,0 +1,36 @@
+=== tests/cases/compiler/substitutionTypesCompareCorrectlyInRestrictiveInstances.ts ===
+type UnionKeys<T> = T extends any ? keyof T : never;
+>UnionKeys : Symbol(UnionKeys, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 0))
+>T : Symbol(T, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 15))
+>T : Symbol(T, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 15))
+>T : Symbol(T, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 15))
+
+type BugHelper<T, TAll> = T extends any ? Exclude<UnionKeys<TAll>, keyof T> : never
+>BugHelper : Symbol(BugHelper, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 52))
+>T : Symbol(T, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 1, 15))
+>TAll : Symbol(TAll, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 1, 17))
+>T : Symbol(T, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 1, 15))
+>Exclude : Symbol(Exclude, Decl(lib.es5.d.ts, --, --))
+>UnionKeys : Symbol(UnionKeys, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 0))
+>TAll : Symbol(TAll, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 1, 17))
+>T : Symbol(T, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 1, 15))
+
+type Bug<TAll> =  BugHelper<TAll, TAll>
+>Bug : Symbol(Bug, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 1, 83))
+>TAll : Symbol(TAll, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 2, 9))
+>BugHelper : Symbol(BugHelper, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 52))
+>TAll : Symbol(TAll, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 2, 9))
+>TAll : Symbol(TAll, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 2, 9))
+
+type Q = UnionKeys<{ a : any } | { b: any }>    // should be "a" | "b"
+>Q : Symbol(Q, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 2, 39))
+>UnionKeys : Symbol(UnionKeys, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 0, 0))
+>a : Symbol(a, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 3, 20))
+>b : Symbol(b, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 3, 34))
+
+type R = Bug<{ a : any } | { b: any }>          // should be "a" | "b"
+>R : Symbol(R, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 3, 44))
+>Bug : Symbol(Bug, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 1, 83))
+>a : Symbol(a, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 4, 14))
+>b : Symbol(b, Decl(substitutionTypesCompareCorrectlyInRestrictiveInstances.ts, 4, 28))
+
diff --git a/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.types b/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.types
new file mode 100644
index 0000000000000..f6c8eb08cd942
--- /dev/null
+++ b/tests/baselines/reference/substitutionTypesCompareCorrectlyInRestrictiveInstances.types
@@ -0,0 +1,20 @@
+=== tests/cases/compiler/substitutionTypesCompareCorrectlyInRestrictiveInstances.ts ===
+type UnionKeys<T> = T extends any ? keyof T : never;
+>UnionKeys : UnionKeys<T>
+
+type BugHelper<T, TAll> = T extends any ? Exclude<UnionKeys<TAll>, keyof T> : never
+>BugHelper : BugHelper<T, TAll>
+
+type Bug<TAll> =  BugHelper<TAll, TAll>
+>Bug : BugHelper<TAll, TAll>
+
+type Q = UnionKeys<{ a : any } | { b: any }>    // should be "a" | "b"
+>Q : "a" | "b"
+>a : any
+>b : any
+
+type R = Bug<{ a : any } | { b: any }>          // should be "a" | "b"
+>R : "a" | "b"
+>a : any
+>b : any
+
diff --git a/tests/cases/compiler/substitutionTypesCompareCorrectlyInRestrictiveInstances.ts b/tests/cases/compiler/substitutionTypesCompareCorrectlyInRestrictiveInstances.ts
new file mode 100644
index 0000000000000..441c556e33127
--- /dev/null
+++ b/tests/cases/compiler/substitutionTypesCompareCorrectlyInRestrictiveInstances.ts
@@ -0,0 +1,6 @@
+// @strict: true
+type UnionKeys<T> = T extends any ? keyof T : never;
+type BugHelper<T, TAll> = T extends any ? Exclude<UnionKeys<TAll>, keyof T> : never
+type Bug<TAll> =  BugHelper<TAll, TAll>
+type Q = UnionKeys<{ a : any } | { b: any }>    // should be "a" | "b"
+type R = Bug<{ a : any } | { b: any }>          // should be "a" | "b"

From d5f32bd7636d0fee1ae3632c40d21c560aa3222f Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Mon, 25 Mar 2019 19:42:52 -0700
Subject: [PATCH 2/5] Strengthen supertype reduction check to reduce breakage

---
 src/compiler/checker.ts                       |  2 +-
 ...nalNoInfiniteInstantiationDepth.errors.txt | 97 -------------------
 ...ditionalNoInfiniteInstantiationDepth.types |  2 +-
 ...plifyingConditionalTypesNoCrash.errors.txt | 78 ---------------
 ...lySimplifyingConditionalTypesNoCrash.types |  2 +-
 5 files changed, 3 insertions(+), 178 deletions(-)
 delete mode 100644 tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt
 delete mode 100644 tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 2cf6c59a3bc3a..e5ec251b19291 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11181,7 +11181,7 @@ namespace ts {
                 }
                 else {
                     const sub = instantiateType((<SubstitutionType>type).substitute, mapper);
-                    if (sub.flags & TypeFlags.AnyOrUnknown || isTypeSubtypeOf(maybeVariable, sub)) {
+                    if (sub.flags & TypeFlags.AnyOrUnknown || isTypeSubtypeOf(getRestrictiveInstantiation(maybeVariable), getRestrictiveInstantiation(sub))) {
                         return maybeVariable;
                     }
                     return sub;
diff --git a/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt b/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt
deleted file mode 100644
index 8ae6eb886fdd4..0000000000000
--- a/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.errors.txt
+++ /dev/null
@@ -1,97 +0,0 @@
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(33,13): error TS2456: Type alias 'Shared' circularly references itself.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(35,35): error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(35,35): error TS2315: Type 'Shared' is not generic.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,15): error TS2313: Type parameter 'P' has a circular constraint.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,76): error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,101): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(37,128): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(63,55): error TS2344: Type 'string | number | symbol' does not satisfy the constraint 'keyof GetProps<C>'.
-  Type 'string' is not assignable to type 'keyof GetProps<C>'.
-tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts(63,61): error TS2315: Type 'Shared' is not generic.
-
-
-==== tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts (9 errors) ====
-    declare class Component<P> {
-        constructor(props: Readonly<P>);
-        constructor(props: P, context?: any);
-        readonly props: Readonly<P> & Readonly<{ children?: {} }>;
-    }
-    interface ComponentClass<P = {}> {
-        new (props: P, context?: any): Component<P>;
-        propTypes?: WeakValidationMap<P>;
-        defaultProps?: Partial<P>;
-        displayName?: string;
-    }
-    interface FunctionComponent<P = {}> {
-        (props: P & { children?: {} }, context?: any): {} | null;
-        propTypes?: WeakValidationMap<P>;
-        defaultProps?: Partial<P>;
-        displayName?: string;
-    }
-    
-    export declare const nominalTypeHack: unique symbol;
-    export interface Validator<T> {
-        (props: object, propName: string, componentName: string, location: string, propFullName: string): Error | null;
-        [nominalTypeHack]?: T;
-    }
-    type WeakValidationMap<T> = {
-        [K in keyof T]?: null extends T[K]
-            ? Validator<T[K] | null | undefined>
-            : undefined extends T[K]
-            ? Validator<T[K] | null | undefined>
-            : Validator<T[K]>
-    };
-    type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
-    
-    export type Shared<
-                ~~~~~~
-!!! error TS2456: Type alias 'Shared' circularly references itself.
-        InjectedProps,
-        DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
-                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
-                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2315: Type 'Shared' is not generic.
-        > = {
-            [P in Extract<keyof InjectedProps, keyof DecorationTargetProps>]?: InjectedProps[P] extends DecorationTargetProps[P] ? DecorationTargetProps[P] : never;
-                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2313: Type parameter 'P' has a circular constraint.
-!!! related TS2751 tests/cases/compiler/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.ts:35:35: Circularity originates in type at this location.
-                                                                               ~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
-                                                                                                        ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-                                                                                                                                   ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-        };
-    
-    // Infers prop type from component C
-    export type GetProps<C> = C extends ComponentType<infer P> ? P : never;
-    
-    export type ConnectedComponentClass<
-        C extends ComponentType<any>,
-        P
-    > = ComponentClass<P> & {
-        WrappedComponent: C;
-    };
-    
-    export type Matching<InjectedProps, DecorationTargetProps> = {
-        [P in keyof DecorationTargetProps]: P extends keyof InjectedProps
-            ? InjectedProps[P] extends DecorationTargetProps[P]
-                ? DecorationTargetProps[P]
-                : InjectedProps[P]
-            : DecorationTargetProps[P];
-    };
-    
-    export type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
-    
-    export type InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> =
-        <C extends ComponentType<Matching<TInjectedProps, GetProps<C>>>>(
-            component: C
-        ) => ConnectedComponentClass<C, Omit<GetProps<C>, keyof Shared<TInjectedProps, GetProps<C>>> & TNeedsProps>;
-                                                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2344: Type 'string | number | symbol' does not satisfy the constraint 'keyof GetProps<C>'.
-!!! error TS2344:   Type 'string' is not assignable to type 'keyof GetProps<C>'.
-                                                                ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2315: Type 'Shared' is not generic.
-    
\ No newline at end of file
diff --git a/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types b/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types
index 357f9195f3572..5bef1baa732a8 100644
--- a/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types
+++ b/tests/baselines/reference/circularlyConstrainedMappedTypeContainingConditionalNoInfiniteInstantiationDepth.types
@@ -79,7 +79,7 @@ type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
 >ComponentType : ComponentType<P>
 
 export type Shared<
->Shared : any
+>Shared : Shared<InjectedProps, DecorationTargetProps>
 
     InjectedProps,
     DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
diff --git a/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt b/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt
deleted file mode 100644
index ef22bdb6f2faf..0000000000000
--- a/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.errors.txt
+++ /dev/null
@@ -1,78 +0,0 @@
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(3,6): error TS2456: Type alias 'Shared' circularly references itself.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(5,35): error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(5,35): error TS2315: Type 'Shared' is not generic.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,15): error TS2313: Type parameter 'P' has a circular constraint.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,75): error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,100): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(7,127): error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(15,16): error TS2315: Type 'Shared' is not generic.
-tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts(17,37): error TS2315: Type 'Shared' is not generic.
-
-
-==== tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts (9 errors) ====
-    type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
-    
-    type Shared< // Circularly self constraining type, defered thanks to mapping
-         ~~~~~~
-!!! error TS2456: Type alias 'Shared' circularly references itself.
-        InjectedProps,
-        DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
-                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2313: Type parameter 'DecorationTargetProps' has a circular constraint.
-                                      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2315: Type 'Shared' is not generic.
-        > = {
-            [P in Extract<keyof InjectedProps, keyof DecorationTargetProps>]: InjectedProps[P] extends DecorationTargetProps[P] ? DecorationTargetProps[P] : never;
-                  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2313: Type parameter 'P' has a circular constraint.
-!!! related TS2751 tests/cases/compiler/circularlySimplifyingConditionalTypesNoCrash.ts:5:35: Circularity originates in type at this location.
-                                                                              ~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'P' cannot be used to index type 'InjectedProps'.
-                                                                                                       ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-                                                                                                                                  ~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2536: Type 'P' cannot be used to index type 'DecorationTargetProps'.
-        };
-    
-    interface ComponentClass<P> {
-        defaultProps?: Partial<P>; // Inference target is also mapped _and_ optional
-    }
-    
-    interface InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> {
-        <P extends Shared<TInjectedProps, P>>(
-                   ~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2315: Type 'Shared' is not generic.
-            component: ComponentClass<P>
-        ): ComponentClass<Omit<P, keyof Shared<TInjectedProps, P>> & TNeedsProps> & { WrappedComponent: ComponentClass<P> }
-                                        ~~~~~~~~~~~~~~~~~~~~~~~~~
-!!! error TS2315: Type 'Shared' is not generic.
-    } // Then intersected with and indexed via Omit and &
-    
-    interface Connect { // Then strictly compared with another signature in its context
-        <TStateProps, TOwnProps>(
-            mapStateToProps: unknown,
-        ): InferableComponentEnhancerWithProps<TStateProps, TOwnProps>;
-    
-        <TDispatchProps, TOwnProps>(
-            mapStateToProps: null | undefined,
-            mapDispatchToProps: unknown,
-            mergeProps: null | undefined,
-            options: unknown
-        ): InferableComponentEnhancerWithProps<TDispatchProps, TOwnProps>;
-    }
-    
-    declare var connect: Connect;
-    
-    const myStoreConnect: Connect = function(
-        mapStateToProps?: any,
-        mapDispatchToProps?: any,
-        mergeProps?: any,
-        options: unknown = {},
-    ) {
-        return connect(
-            mapStateToProps,
-            mapDispatchToProps,
-            mergeProps,
-            options,
-        );
-    };
\ No newline at end of file
diff --git a/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types b/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types
index 74bdbec990ad4..4a3a1fdbe53aa 100644
--- a/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types
+++ b/tests/baselines/reference/circularlySimplifyingConditionalTypesNoCrash.types
@@ -3,7 +3,7 @@ type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
 >Omit : Pick<T, Exclude<keyof T, K>>
 
 type Shared< // Circularly self constraining type, defered thanks to mapping
->Shared : any
+>Shared : Shared<InjectedProps, DecorationTargetProps>
 
     InjectedProps,
     DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>

From d28ad011b063456b3599e159e4e80a5ccc490e00 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Tue, 26 Mar 2019 10:35:50 -0700
Subject: [PATCH 3/5] Rename conditional type fields per convention

---
 src/compiler/checker.ts                       | 28 +++++++++----------
 src/compiler/types.ts                         |  6 ++--
 .../reference/api/tsserverlibrary.d.ts        |  4 +--
 tests/baselines/reference/api/typescript.d.ts |  4 +--
 4 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index e5ec251b19291..b652de00f858c 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -3492,8 +3492,8 @@ namespace ts {
                     context.inferTypeParameters = (<ConditionalType>type).root.inferTypeParameters;
                     const extendsTypeNode = typeToTypeNodeHelper((<ConditionalType>type).extendsType, context);
                     context.inferTypeParameters = saveInferTypeParameters;
-                    const trueTypeNode = typeToTypeNodeHelper((<ConditionalType>type).resolvedTrueType, context);
-                    const falseTypeNode = typeToTypeNodeHelper((<ConditionalType>type).resolvedFalseType, context);
+                    const trueTypeNode = typeToTypeNodeHelper((<ConditionalType>type).trueType, context);
+                    const falseTypeNode = typeToTypeNodeHelper((<ConditionalType>type).falseType, context);
                     context.approximateLength += 15;
                     return createConditionalTypeNode(checkTypeNode, extendsTypeNode, trueTypeNode, falseTypeNode);
                 }
@@ -7499,7 +7499,7 @@ namespace ts {
                 // just `any`. This result is _usually_ unwanted - so instead here we elide an `any` branch from the constraint type,
                 // in effect treating `any` like `never` rather than `unknown` in this location.
                 const trueConstraint = getInferredTrueTypeFromConditionalType(type);
-                const falseConstraint = type.resolvedFalseType;
+                const falseConstraint = type.falseType;
                 type.resolvedDefaultConstraint = isTypeAny(trueConstraint) ? falseConstraint : isTypeAny(falseConstraint) ? trueConstraint : getUnionType([trueConstraint, falseConstraint]);
             }
             return type.resolvedDefaultConstraint;
@@ -10231,15 +10231,15 @@ namespace ts {
             result.extendsType = extendsType;
             result.mapper = mapper;
             result.combinedMapper = combinedMapper;
-            result.resolvedTrueType = trueType;
-            result.resolvedFalseType = falseType;
+            result.trueType = trueType;
+            result.falseType = falseType;
             result.aliasSymbol = root.aliasSymbol;
             result.aliasTypeArguments = instantiateTypes(root.aliasTypeArguments, mapper!); // TODO: GH#18217
             return result;
         }
 
         function getInferredTrueTypeFromConditionalType(type: ConditionalType) {
-            return type.inferredTrueType || (type.inferredTrueType = instantiateType(type.root.trueType, type.combinedMapper || type.mapper));
+            return type.resolvedInferredTrueType || (type.resolvedInferredTrueType = instantiateType(type.root.trueType, type.combinedMapper || type.mapper));
         }
 
         function getInferTypeParameters(node: ConditionalTypeNode): TypeParameter[] | undefined {
@@ -12708,8 +12708,8 @@ namespace ts {
                         if ((<ConditionalType>source).root.isDistributive === (<ConditionalType>target).root.isDistributive) {
                             if (result = isRelatedTo((<ConditionalType>source).checkType, (<ConditionalType>target).checkType, /*reportErrors*/ false)) {
                                 if (result &= isRelatedTo((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType, /*reportErrors*/ false)) {
-                                    if (result &= isRelatedTo((<ConditionalType>source).resolvedTrueType, (<ConditionalType>target).resolvedTrueType, /*reportErrors*/ false)) {
-                                        if (result &= isRelatedTo((<ConditionalType>source).resolvedFalseType, (<ConditionalType>target).resolvedFalseType, /*reportErrors*/ false)) {
+                                    if (result &= isRelatedTo((<ConditionalType>source).trueType, (<ConditionalType>target).trueType, /*reportErrors*/ false)) {
+                                        if (result &= isRelatedTo((<ConditionalType>source).falseType, (<ConditionalType>target).falseType, /*reportErrors*/ false)) {
                                             return result;
                                         }
                                     }
@@ -12862,8 +12862,8 @@ namespace ts {
                         // and Y1 is related to Y2.
                         if (isTypeIdenticalTo((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType) &&
                             (isRelatedTo((<ConditionalType>source).checkType, (<ConditionalType>target).checkType) || isRelatedTo((<ConditionalType>target).checkType, (<ConditionalType>source).checkType))) {
-                            if (result = isRelatedTo((<ConditionalType>source).resolvedTrueType, (<ConditionalType>target).resolvedTrueType, reportErrors)) {
-                                result &= isRelatedTo((<ConditionalType>source).resolvedFalseType, (<ConditionalType>target).resolvedFalseType, reportErrors);
+                            if (result = isRelatedTo((<ConditionalType>source).trueType, (<ConditionalType>target).trueType, reportErrors)) {
+                                result &= isRelatedTo((<ConditionalType>source).falseType, (<ConditionalType>target).falseType, reportErrors);
                             }
                             if (result) {
                                 errorInfo = saveErrorInfo;
@@ -14698,12 +14698,12 @@ namespace ts {
                 else if (source.flags & TypeFlags.Conditional && target.flags & TypeFlags.Conditional) {
                     inferFromTypes((<ConditionalType>source).checkType, (<ConditionalType>target).checkType);
                     inferFromTypes((<ConditionalType>source).extendsType, (<ConditionalType>target).extendsType);
-                    inferFromTypes((<ConditionalType>source).resolvedTrueType, (<ConditionalType>target).resolvedTrueType);
-                    inferFromTypes((<ConditionalType>source).resolvedFalseType, (<ConditionalType>target).resolvedFalseType);
+                    inferFromTypes((<ConditionalType>source).trueType, (<ConditionalType>target).trueType);
+                    inferFromTypes((<ConditionalType>source).falseType, (<ConditionalType>target).falseType);
                 }
                 else if (target.flags & TypeFlags.Conditional && !contravariant) {
-                    inferFromTypes(source, (<ConditionalType>target).resolvedTrueType);
-                    inferFromTypes(source, (<ConditionalType>target).resolvedFalseType);
+                    inferFromTypes(source, (<ConditionalType>target).trueType);
+                    inferFromTypes(source, (<ConditionalType>target).falseType);
                 }
                 else if (target.flags & TypeFlags.UnionOrIntersection) {
                     for (const t of (<UnionOrIntersectionType>target).types) {
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index c98bf55013616..bcc3218a017e7 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -4310,10 +4310,10 @@ namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType: Type;
-        resolvedFalseType: Type;
+        trueType: Type;
+        falseType: Type;
         /* @internal */
-        inferredTrueType?: Type; // The `trueType` instantiated with the `combinedMapper`, if present
+        resolvedInferredTrueType?: Type; // The `trueType` instantiated with the `combinedMapper`, if present
         /* @internal */
         resolvedDefaultConstraint?: Type;
         /* @internal */
diff --git a/tests/baselines/reference/api/tsserverlibrary.d.ts b/tests/baselines/reference/api/tsserverlibrary.d.ts
index a84867f52fd38..8208cdba2ab46 100644
--- a/tests/baselines/reference/api/tsserverlibrary.d.ts
+++ b/tests/baselines/reference/api/tsserverlibrary.d.ts
@@ -2382,8 +2382,8 @@ declare namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType: Type;
-        resolvedFalseType: Type;
+        trueType: Type;
+        falseType: Type;
     }
     interface SubstitutionType extends InstantiableType {
         typeVariable: TypeVariable;
diff --git a/tests/baselines/reference/api/typescript.d.ts b/tests/baselines/reference/api/typescript.d.ts
index bec7f9faf9f45..314ccf298cf28 100644
--- a/tests/baselines/reference/api/typescript.d.ts
+++ b/tests/baselines/reference/api/typescript.d.ts
@@ -2382,8 +2382,8 @@ declare namespace ts {
         root: ConditionalRoot;
         checkType: Type;
         extendsType: Type;
-        resolvedTrueType: Type;
-        resolvedFalseType: Type;
+        trueType: Type;
+        falseType: Type;
     }
     interface SubstitutionType extends InstantiableType {
         typeVariable: TypeVariable;

From 73e3733d2528fde7415cabf912a689dc807d6740 Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Tue, 26 Mar 2019 13:13:39 -0700
Subject: [PATCH 4/5] Explicitly handle anyish signatures in
 compareSignaturesRelated so strict variance doesnt kill subtyping

---
 src/compiler/checker.ts                       |  13 +
 ...uxLikeDeferredInferenceAllowsAssignment.js | 219 ++++++++
 ...eDeferredInferenceAllowsAssignment.symbols | 471 ++++++++++++++++++
 ...ikeDeferredInferenceAllowsAssignment.types | 288 +++++++++++
 ...uxLikeDeferredInferenceAllowsAssignment.ts | 145 ++++++
 5 files changed, 1136 insertions(+)
 create mode 100644 tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js
 create mode 100644 tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.symbols
 create mode 100644 tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.types
 create mode 100644 tests/cases/compiler/reactReduxLikeDeferredInferenceAllowsAssignment.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index b652de00f858c..34391510b343a 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11729,6 +11729,15 @@ namespace ts {
 
         type ErrorReporter = (message: DiagnosticMessage, arg0?: string, arg1?: string) => void;
 
+        /**
+         * Returns true if `s` is `(...args: any[]) => any` or `(this: any, ...args: any[]) => any`
+         */
+        function isAnySignature(s: Signature) {
+            return !s.typeParameters && (!s.thisParameter || isTypeAny(getTypeOfParameter(s.thisParameter))) && s.parameters.length === 1 &&
+                s.hasRestParameter && getTypeOfParameter(s.parameters[0]) === anyArrayType &&
+                isTypeAny(getReturnTypeOfSignature(s));
+        }
+
         /**
          * See signatureRelatedTo, compareSignaturesIdentical
          */
@@ -11744,6 +11753,10 @@ namespace ts {
                 return Ternary.True;
             }
 
+            if (isAnySignature(target)) {
+                return Ternary.True;
+            }
+
             const targetCount = getParameterCount(target);
             if (!hasEffectiveRestParameter(target) && getMinArgumentCount(source) > targetCount) {
                 return Ternary.False;
diff --git a/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js
new file mode 100644
index 0000000000000..2eeda64fc989b
--- /dev/null
+++ b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.js
@@ -0,0 +1,219 @@
+//// [reactReduxLikeDeferredInferenceAllowsAssignment.ts]
+declare class Component<P> {
+  constructor(props: Readonly<P>);
+  constructor(props: P, context?: any);
+  readonly props: Readonly<P> & Readonly<{ children?: {} }>;
+}
+interface ComponentClass<P = {}> {
+  new (props: P, context?: any): Component<P>;
+  propTypes?: WeakValidationMap<P>;
+  defaultProps?: Partial<P>;
+  displayName?: string;
+}
+interface FunctionComponent<P = {}> {
+  (props: P & { children?: {} }, context?: any): {} | null;
+  propTypes?: WeakValidationMap<P>;
+  defaultProps?: Partial<P>;
+  displayName?: string;
+}
+
+declare const nominalTypeHack: unique symbol;
+interface Validator<T> {
+  (
+    props: object,
+    propName: string,
+    componentName: string,
+    location: string,
+    propFullName: string
+  ): Error | null;
+  [nominalTypeHack]?: T;
+}
+type WeakValidationMap<T> = {
+  [K in keyof T]?: null extends T[K]
+    ? Validator<T[K] | null | undefined>
+    : undefined extends T[K]
+    ? Validator<T[K] | null | undefined>
+    : Validator<T[K]>
+};
+type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
+
+type Shared<
+  InjectedProps,
+  DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
+> = {
+  [P in Extract<
+    keyof InjectedProps,
+    keyof DecorationTargetProps
+  >]?: InjectedProps[P] extends DecorationTargetProps[P]
+    ? DecorationTargetProps[P]
+    : never
+};
+
+// Infers prop type from component C
+type GetProps<C> = C extends ComponentType<infer P> ? P : never;
+
+type ConnectedComponentClass<C extends ComponentType<any>, P> = ComponentClass<
+  P
+> & {
+  WrappedComponent: C;
+};
+
+type Matching<InjectedProps, DecorationTargetProps> = {
+  [P in keyof DecorationTargetProps]: P extends keyof InjectedProps
+    ? InjectedProps[P] extends DecorationTargetProps[P]
+      ? DecorationTargetProps[P]
+      : InjectedProps[P]
+    : DecorationTargetProps[P]
+};
+
+type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
+
+type InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> = <
+  C extends ComponentType<Matching<TInjectedProps, GetProps<C>>>
+>(
+  component: C
+) => ConnectedComponentClass<
+  C,
+  Omit<GetProps<C>, keyof Shared<TInjectedProps, GetProps<C>>> & TNeedsProps
+>;
+
+declare const connect: {
+  <no_state = {}, TDispatchProps = {}, TOwnProps = {}>(
+    mapStateToProps: null | undefined,
+    mapDispatchToProps: TDispatchProps
+  ): InferableComponentEnhancerWithProps<
+    ResolveThunks<TDispatchProps>,
+    TOwnProps
+  >;
+};
+
+type InferThunkActionCreatorType<
+  TActionCreator extends (...args: any[]) => any
+> = TActionCreator extends (
+  ...args: infer TParams
+) => (...args: any[]) => infer TReturn
+  ? (...args: TParams) => TReturn
+  : TActionCreator;
+
+type HandleThunkActionCreator<TActionCreator> = TActionCreator extends (
+  ...args: any[]
+) => any
+  ? InferThunkActionCreatorType<TActionCreator>
+  : TActionCreator;
+
+type ResolveThunks<TDispatchProps> = TDispatchProps extends {
+  [key: string]: any;
+}
+  ? { [C in keyof TDispatchProps]: HandleThunkActionCreator<TDispatchProps[C]> }
+  : TDispatchProps;
+
+interface Dispatch<A extends Action = AnyAction> {
+  <T extends A>(action: T): T;
+}
+interface Action<T = any> {
+  type: T;
+}
+interface AnyAction extends Action {
+  [extraProps: string]: any;
+}
+
+const simpleAction = (payload: boolean) => ({
+  type: "SIMPLE_ACTION",
+  payload
+});
+const thunkAction = (param1: number, param2: string) => async (
+  dispatch: Dispatch,
+  { foo }: OwnProps
+) => {
+  return foo;
+};
+interface OwnProps {
+  foo: string;
+}
+interface TestComponentProps extends OwnProps {
+  simpleAction: typeof simpleAction;
+  thunkAction(param1: number, param2: string): Promise<string>;
+}
+class TestComponent extends Component<TestComponentProps> {}
+const mapDispatchToProps = { simpleAction, thunkAction };
+
+type Q = HandleThunkActionCreator<typeof simpleAction>;
+
+const Test1 = connect(
+  null,
+  mapDispatchToProps
+)(TestComponent);
+
+
+//// [reactReduxLikeDeferredInferenceAllowsAssignment.js]
+"use strict";
+var __extends = (this && this.__extends) || (function () {
+    var extendStatics = function (d, b) {
+        extendStatics = Object.setPrototypeOf ||
+            ({ __proto__: [] } instanceof Array && function (d, b) { d.__proto__ = b; }) ||
+            function (d, b) { for (var p in b) if (b.hasOwnProperty(p)) d[p] = b[p]; };
+        return extendStatics(d, b);
+    };
+    return function (d, b) {
+        extendStatics(d, b);
+        function __() { this.constructor = d; }
+        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    };
+})();
+var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, generator) {
+    return new (P || (P = Promise))(function (resolve, reject) {
+        function fulfilled(value) { try { step(generator.next(value)); } catch (e) { reject(e); } }
+        function rejected(value) { try { step(generator["throw"](value)); } catch (e) { reject(e); } }
+        function step(result) { result.done ? resolve(result.value) : new P(function (resolve) { resolve(result.value); }).then(fulfilled, rejected); }
+        step((generator = generator.apply(thisArg, _arguments || [])).next());
+    });
+};
+var __generator = (this && this.__generator) || function (thisArg, body) {
+    var _ = { label: 0, sent: function() { if (t[0] & 1) throw t[1]; return t[1]; }, trys: [], ops: [] }, f, y, t, g;
+    return g = { next: verb(0), "throw": verb(1), "return": verb(2) }, typeof Symbol === "function" && (g[Symbol.iterator] = function() { return this; }), g;
+    function verb(n) { return function (v) { return step([n, v]); }; }
+    function step(op) {
+        if (f) throw new TypeError("Generator is already executing.");
+        while (_) try {
+            if (f = 1, y && (t = op[0] & 2 ? y["return"] : op[0] ? y["throw"] || ((t = y["return"]) && t.call(y), 0) : y.next) && !(t = t.call(y, op[1])).done) return t;
+            if (y = 0, t) op = [op[0] & 2, t.value];
+            switch (op[0]) {
+                case 0: case 1: t = op; break;
+                case 4: _.label++; return { value: op[1], done: false };
+                case 5: _.label++; y = op[1]; op = [0]; continue;
+                case 7: op = _.ops.pop(); _.trys.pop(); continue;
+                default:
+                    if (!(t = _.trys, t = t.length > 0 && t[t.length - 1]) && (op[0] === 6 || op[0] === 2)) { _ = 0; continue; }
+                    if (op[0] === 3 && (!t || (op[1] > t[0] && op[1] < t[3]))) { _.label = op[1]; break; }
+                    if (op[0] === 6 && _.label < t[1]) { _.label = t[1]; t = op; break; }
+                    if (t && _.label < t[2]) { _.label = t[2]; _.ops.push(op); break; }
+                    if (t[2]) _.ops.pop();
+                    _.trys.pop(); continue;
+            }
+            op = body.call(thisArg, _);
+        } catch (e) { op = [6, e]; y = 0; } finally { f = t = 0; }
+        if (op[0] & 5) throw op[1]; return { value: op[0] ? op[1] : void 0, done: true };
+    }
+};
+var _this = this;
+var simpleAction = function (payload) { return ({
+    type: "SIMPLE_ACTION",
+    payload: payload
+}); };
+var thunkAction = function (param1, param2) { return function (dispatch, _a) {
+    var foo = _a.foo;
+    return __awaiter(_this, void 0, void 0, function () {
+        return __generator(this, function (_b) {
+            return [2 /*return*/, foo];
+        });
+    });
+}; };
+var TestComponent = /** @class */ (function (_super) {
+    __extends(TestComponent, _super);
+    function TestComponent() {
+        return _super !== null && _super.apply(this, arguments) || this;
+    }
+    return TestComponent;
+}(Component));
+var mapDispatchToProps = { simpleAction: simpleAction, thunkAction: thunkAction };
+var Test1 = connect(null, mapDispatchToProps)(TestComponent);
diff --git a/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.symbols b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.symbols
new file mode 100644
index 0000000000000..ec954dfde7951
--- /dev/null
+++ b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.symbols
@@ -0,0 +1,471 @@
+=== tests/cases/compiler/reactReduxLikeDeferredInferenceAllowsAssignment.ts ===
+declare class Component<P> {
+>Component : Symbol(Component, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 0, 0))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 0, 24))
+
+  constructor(props: Readonly<P>);
+>props : Symbol(props, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 1, 14))
+>Readonly : Symbol(Readonly, Decl(lib.es5.d.ts, --, --))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 0, 24))
+
+  constructor(props: P, context?: any);
+>props : Symbol(props, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 2, 14))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 0, 24))
+>context : Symbol(context, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 2, 23))
+
+  readonly props: Readonly<P> & Readonly<{ children?: {} }>;
+>props : Symbol(Component.props, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 2, 39))
+>Readonly : Symbol(Readonly, Decl(lib.es5.d.ts, --, --))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 0, 24))
+>Readonly : Symbol(Readonly, Decl(lib.es5.d.ts, --, --))
+>children : Symbol(children, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 3, 42))
+}
+interface ComponentClass<P = {}> {
+>ComponentClass : Symbol(ComponentClass, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 4, 1))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 5, 25))
+
+  new (props: P, context?: any): Component<P>;
+>props : Symbol(props, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 6, 7))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 5, 25))
+>context : Symbol(context, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 6, 16))
+>Component : Symbol(Component, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 0, 0))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 5, 25))
+
+  propTypes?: WeakValidationMap<P>;
+>propTypes : Symbol(ComponentClass.propTypes, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 6, 46))
+>WeakValidationMap : Symbol(WeakValidationMap, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 28, 1))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 5, 25))
+
+  defaultProps?: Partial<P>;
+>defaultProps : Symbol(ComponentClass.defaultProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 7, 35))
+>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 5, 25))
+
+  displayName?: string;
+>displayName : Symbol(ComponentClass.displayName, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 8, 28))
+}
+interface FunctionComponent<P = {}> {
+>FunctionComponent : Symbol(FunctionComponent, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 10, 1))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 11, 28))
+
+  (props: P & { children?: {} }, context?: any): {} | null;
+>props : Symbol(props, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 12, 3))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 11, 28))
+>children : Symbol(children, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 12, 15))
+>context : Symbol(context, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 12, 32))
+
+  propTypes?: WeakValidationMap<P>;
+>propTypes : Symbol(FunctionComponent.propTypes, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 12, 59))
+>WeakValidationMap : Symbol(WeakValidationMap, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 28, 1))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 11, 28))
+
+  defaultProps?: Partial<P>;
+>defaultProps : Symbol(FunctionComponent.defaultProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 13, 35))
+>Partial : Symbol(Partial, Decl(lib.es5.d.ts, --, --))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 11, 28))
+
+  displayName?: string;
+>displayName : Symbol(FunctionComponent.displayName, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 14, 28))
+}
+
+declare const nominalTypeHack: unique symbol;
+>nominalTypeHack : Symbol(nominalTypeHack, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 18, 13))
+
+interface Validator<T> {
+>Validator : Symbol(Validator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 18, 45))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 19, 20))
+
+  (
+    props: object,
+>props : Symbol(props, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 20, 3))
+
+    propName: string,
+>propName : Symbol(propName, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 21, 18))
+
+    componentName: string,
+>componentName : Symbol(componentName, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 22, 21))
+
+    location: string,
+>location : Symbol(location, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 23, 26))
+
+    propFullName: string
+>propFullName : Symbol(propFullName, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 24, 21))
+
+  ): Error | null;
+>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+  [nominalTypeHack]?: T;
+>[nominalTypeHack] : Symbol(Validator[nominalTypeHack], Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 26, 18))
+>nominalTypeHack : Symbol(nominalTypeHack, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 18, 13))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 19, 20))
+}
+type WeakValidationMap<T> = {
+>WeakValidationMap : Symbol(WeakValidationMap, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 28, 1))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 29, 23))
+
+  [K in keyof T]?: null extends T[K]
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 30, 3))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 29, 23))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 29, 23))
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 30, 3))
+
+    ? Validator<T[K] | null | undefined>
+>Validator : Symbol(Validator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 18, 45))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 29, 23))
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 30, 3))
+
+    : undefined extends T[K]
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 29, 23))
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 30, 3))
+
+    ? Validator<T[K] | null | undefined>
+>Validator : Symbol(Validator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 18, 45))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 29, 23))
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 30, 3))
+
+    : Validator<T[K]>
+>Validator : Symbol(Validator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 18, 45))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 29, 23))
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 30, 3))
+
+};
+type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
+>ComponentType : Symbol(ComponentType, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 35, 2))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 36, 19))
+>ComponentClass : Symbol(ComponentClass, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 4, 1))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 36, 19))
+>FunctionComponent : Symbol(FunctionComponent, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 10, 1))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 36, 19))
+
+type Shared<
+>Shared : Symbol(Shared, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 36, 70))
+
+  InjectedProps,
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 38, 12))
+
+  DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 39, 16))
+>Shared : Symbol(Shared, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 36, 70))
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 38, 12))
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 39, 16))
+
+> = {
+  [P in Extract<
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 42, 3))
+>Extract : Symbol(Extract, Decl(lib.es5.d.ts, --, --))
+
+    keyof InjectedProps,
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 38, 12))
+
+    keyof DecorationTargetProps
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 39, 16))
+
+  >]?: InjectedProps[P] extends DecorationTargetProps[P]
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 38, 12))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 42, 3))
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 39, 16))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 42, 3))
+
+    ? DecorationTargetProps[P]
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 39, 16))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 42, 3))
+
+    : never
+};
+
+// Infers prop type from component C
+type GetProps<C> = C extends ComponentType<infer P> ? P : never;
+>GetProps : Symbol(GetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 48, 2))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 51, 14))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 51, 14))
+>ComponentType : Symbol(ComponentType, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 35, 2))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 51, 48))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 51, 48))
+
+type ConnectedComponentClass<C extends ComponentType<any>, P> = ComponentClass<
+>ConnectedComponentClass : Symbol(ConnectedComponentClass, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 51, 64))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 53, 29))
+>ComponentType : Symbol(ComponentType, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 35, 2))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 53, 58))
+>ComponentClass : Symbol(ComponentClass, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 4, 1))
+
+  P
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 53, 58))
+
+> & {
+  WrappedComponent: C;
+>WrappedComponent : Symbol(WrappedComponent, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 55, 5))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 53, 29))
+
+};
+
+type Matching<InjectedProps, DecorationTargetProps> = {
+>Matching : Symbol(Matching, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 57, 2))
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 14))
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 28))
+
+  [P in keyof DecorationTargetProps]: P extends keyof InjectedProps
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 60, 3))
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 28))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 60, 3))
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 14))
+
+    ? InjectedProps[P] extends DecorationTargetProps[P]
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 14))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 60, 3))
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 28))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 60, 3))
+
+      ? DecorationTargetProps[P]
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 28))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 60, 3))
+
+      : InjectedProps[P]
+>InjectedProps : Symbol(InjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 14))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 60, 3))
+
+    : DecorationTargetProps[P]
+>DecorationTargetProps : Symbol(DecorationTargetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 59, 28))
+>P : Symbol(P, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 60, 3))
+
+};
+
+type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
+>Omit : Symbol(Omit, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 65, 2))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 10))
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 12))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 10))
+>Pick : Symbol(Pick, Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 10))
+>Exclude : Symbol(Exclude, Decl(lib.es5.d.ts, --, --))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 10))
+>K : Symbol(K, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 12))
+
+type InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> = <
+>InferableComponentEnhancerWithProps : Symbol(InferableComponentEnhancerWithProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 63))
+>TInjectedProps : Symbol(TInjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 41))
+>TNeedsProps : Symbol(TNeedsProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 56))
+
+  C extends ComponentType<Matching<TInjectedProps, GetProps<C>>>
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 73))
+>ComponentType : Symbol(ComponentType, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 35, 2))
+>Matching : Symbol(Matching, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 57, 2))
+>TInjectedProps : Symbol(TInjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 41))
+>GetProps : Symbol(GetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 48, 2))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 73))
+
+>(
+  component: C
+>component : Symbol(component, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 71, 2))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 73))
+
+) => ConnectedComponentClass<
+>ConnectedComponentClass : Symbol(ConnectedComponentClass, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 51, 64))
+
+  C,
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 73))
+
+  Omit<GetProps<C>, keyof Shared<TInjectedProps, GetProps<C>>> & TNeedsProps
+>Omit : Symbol(Omit, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 65, 2))
+>GetProps : Symbol(GetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 48, 2))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 73))
+>Shared : Symbol(Shared, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 36, 70))
+>TInjectedProps : Symbol(TInjectedProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 41))
+>GetProps : Symbol(GetProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 48, 2))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 73))
+>TNeedsProps : Symbol(TNeedsProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 69, 56))
+
+>;
+
+declare const connect: {
+>connect : Symbol(connect, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 78, 13))
+
+  <no_state = {}, TDispatchProps = {}, TOwnProps = {}>(
+>no_state : Symbol(no_state, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 79, 3))
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 79, 17))
+>TOwnProps : Symbol(TOwnProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 79, 38))
+
+    mapStateToProps: null | undefined,
+>mapStateToProps : Symbol(mapStateToProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 79, 55))
+
+    mapDispatchToProps: TDispatchProps
+>mapDispatchToProps : Symbol(mapDispatchToProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 80, 38))
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 79, 17))
+
+  ): InferableComponentEnhancerWithProps<
+>InferableComponentEnhancerWithProps : Symbol(InferableComponentEnhancerWithProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 67, 63))
+
+    ResolveThunks<TDispatchProps>,
+>ResolveThunks : Symbol(ResolveThunks, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 100, 19))
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 79, 17))
+
+    TOwnProps
+>TOwnProps : Symbol(TOwnProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 79, 38))
+
+  >;
+};
+
+type InferThunkActionCreatorType<
+>InferThunkActionCreatorType : Symbol(InferThunkActionCreatorType, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 86, 2))
+
+  TActionCreator extends (...args: any[]) => any
+>TActionCreator : Symbol(TActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 88, 33))
+>args : Symbol(args, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 89, 26))
+
+> = TActionCreator extends (
+>TActionCreator : Symbol(TActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 88, 33))
+
+  ...args: infer TParams
+>args : Symbol(args, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 90, 28))
+>TParams : Symbol(TParams, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 91, 16))
+
+) => (...args: any[]) => infer TReturn
+>args : Symbol(args, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 92, 6))
+>TReturn : Symbol(TReturn, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 92, 30))
+
+  ? (...args: TParams) => TReturn
+>args : Symbol(args, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 93, 5))
+>TParams : Symbol(TParams, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 91, 16))
+>TReturn : Symbol(TReturn, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 92, 30))
+
+  : TActionCreator;
+>TActionCreator : Symbol(TActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 88, 33))
+
+type HandleThunkActionCreator<TActionCreator> = TActionCreator extends (
+>HandleThunkActionCreator : Symbol(HandleThunkActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 94, 19))
+>TActionCreator : Symbol(TActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 96, 30))
+>TActionCreator : Symbol(TActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 96, 30))
+
+  ...args: any[]
+>args : Symbol(args, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 96, 72))
+
+) => any
+  ? InferThunkActionCreatorType<TActionCreator>
+>InferThunkActionCreatorType : Symbol(InferThunkActionCreatorType, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 86, 2))
+>TActionCreator : Symbol(TActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 96, 30))
+
+  : TActionCreator;
+>TActionCreator : Symbol(TActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 96, 30))
+
+type ResolveThunks<TDispatchProps> = TDispatchProps extends {
+>ResolveThunks : Symbol(ResolveThunks, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 100, 19))
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 102, 19))
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 102, 19))
+
+  [key: string]: any;
+>key : Symbol(key, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 103, 3))
+}
+  ? { [C in keyof TDispatchProps]: HandleThunkActionCreator<TDispatchProps[C]> }
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 105, 7))
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 102, 19))
+>HandleThunkActionCreator : Symbol(HandleThunkActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 94, 19))
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 102, 19))
+>C : Symbol(C, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 105, 7))
+
+  : TDispatchProps;
+>TDispatchProps : Symbol(TDispatchProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 102, 19))
+
+interface Dispatch<A extends Action = AnyAction> {
+>Dispatch : Symbol(Dispatch, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 106, 19))
+>A : Symbol(A, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 108, 19))
+>Action : Symbol(Action, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 110, 1))
+>AnyAction : Symbol(AnyAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 113, 1))
+
+  <T extends A>(action: T): T;
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 109, 3))
+>A : Symbol(A, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 108, 19))
+>action : Symbol(action, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 109, 16))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 109, 3))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 109, 3))
+}
+interface Action<T = any> {
+>Action : Symbol(Action, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 110, 1))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 111, 17))
+
+  type: T;
+>type : Symbol(Action.type, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 111, 27))
+>T : Symbol(T, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 111, 17))
+}
+interface AnyAction extends Action {
+>AnyAction : Symbol(AnyAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 113, 1))
+>Action : Symbol(Action, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 110, 1))
+
+  [extraProps: string]: any;
+>extraProps : Symbol(extraProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 115, 3))
+}
+
+const simpleAction = (payload: boolean) => ({
+>simpleAction : Symbol(simpleAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 118, 5))
+>payload : Symbol(payload, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 118, 22))
+
+  type: "SIMPLE_ACTION",
+>type : Symbol(type, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 118, 45))
+
+  payload
+>payload : Symbol(payload, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 119, 24))
+
+});
+const thunkAction = (param1: number, param2: string) => async (
+>thunkAction : Symbol(thunkAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 122, 5))
+>param1 : Symbol(param1, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 122, 21))
+>param2 : Symbol(param2, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 122, 36))
+
+  dispatch: Dispatch,
+>dispatch : Symbol(dispatch, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 122, 63))
+>Dispatch : Symbol(Dispatch, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 106, 19))
+
+  { foo }: OwnProps
+>foo : Symbol(foo, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 124, 3))
+>OwnProps : Symbol(OwnProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 127, 2))
+
+) => {
+  return foo;
+>foo : Symbol(foo, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 124, 3))
+
+};
+interface OwnProps {
+>OwnProps : Symbol(OwnProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 127, 2))
+
+  foo: string;
+>foo : Symbol(OwnProps.foo, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 128, 20))
+}
+interface TestComponentProps extends OwnProps {
+>TestComponentProps : Symbol(TestComponentProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 130, 1))
+>OwnProps : Symbol(OwnProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 127, 2))
+
+  simpleAction: typeof simpleAction;
+>simpleAction : Symbol(TestComponentProps.simpleAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 131, 47))
+>simpleAction : Symbol(simpleAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 118, 5))
+
+  thunkAction(param1: number, param2: string): Promise<string>;
+>thunkAction : Symbol(TestComponentProps.thunkAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 132, 36))
+>param1 : Symbol(param1, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 133, 14))
+>param2 : Symbol(param2, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 133, 29))
+>Promise : Symbol(Promise, Decl(lib.es5.d.ts, --, --))
+}
+class TestComponent extends Component<TestComponentProps> {}
+>TestComponent : Symbol(TestComponent, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 134, 1))
+>Component : Symbol(Component, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 0, 0))
+>TestComponentProps : Symbol(TestComponentProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 130, 1))
+
+const mapDispatchToProps = { simpleAction, thunkAction };
+>mapDispatchToProps : Symbol(mapDispatchToProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 136, 5))
+>simpleAction : Symbol(simpleAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 136, 28))
+>thunkAction : Symbol(thunkAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 136, 42))
+
+type Q = HandleThunkActionCreator<typeof simpleAction>;
+>Q : Symbol(Q, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 136, 57))
+>HandleThunkActionCreator : Symbol(HandleThunkActionCreator, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 94, 19))
+>simpleAction : Symbol(simpleAction, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 118, 5))
+
+const Test1 = connect(
+>Test1 : Symbol(Test1, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 140, 5))
+>connect : Symbol(connect, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 78, 13))
+
+  null,
+  mapDispatchToProps
+>mapDispatchToProps : Symbol(mapDispatchToProps, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 136, 5))
+
+)(TestComponent);
+>TestComponent : Symbol(TestComponent, Decl(reactReduxLikeDeferredInferenceAllowsAssignment.ts, 134, 1))
+
diff --git a/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.types b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.types
new file mode 100644
index 0000000000000..767d94535cbc9
--- /dev/null
+++ b/tests/baselines/reference/reactReduxLikeDeferredInferenceAllowsAssignment.types
@@ -0,0 +1,288 @@
+=== tests/cases/compiler/reactReduxLikeDeferredInferenceAllowsAssignment.ts ===
+declare class Component<P> {
+>Component : Component<P>
+
+  constructor(props: Readonly<P>);
+>props : Readonly<P>
+
+  constructor(props: P, context?: any);
+>props : P
+>context : any
+
+  readonly props: Readonly<P> & Readonly<{ children?: {} }>;
+>props : Readonly<P> & Readonly<{ children?: {} | undefined; }>
+>children : {} | undefined
+}
+interface ComponentClass<P = {}> {
+  new (props: P, context?: any): Component<P>;
+>props : P
+>context : any
+
+  propTypes?: WeakValidationMap<P>;
+>propTypes : WeakValidationMap<P> | undefined
+
+  defaultProps?: Partial<P>;
+>defaultProps : Partial<P> | undefined
+
+  displayName?: string;
+>displayName : string | undefined
+}
+interface FunctionComponent<P = {}> {
+  (props: P & { children?: {} }, context?: any): {} | null;
+>props : P & { children?: {} | undefined; }
+>children : {} | undefined
+>context : any
+>null : null
+
+  propTypes?: WeakValidationMap<P>;
+>propTypes : WeakValidationMap<P> | undefined
+
+  defaultProps?: Partial<P>;
+>defaultProps : Partial<P> | undefined
+
+  displayName?: string;
+>displayName : string | undefined
+}
+
+declare const nominalTypeHack: unique symbol;
+>nominalTypeHack : unique symbol
+
+interface Validator<T> {
+  (
+    props: object,
+>props : object
+
+    propName: string,
+>propName : string
+
+    componentName: string,
+>componentName : string
+
+    location: string,
+>location : string
+
+    propFullName: string
+>propFullName : string
+
+  ): Error | null;
+>null : null
+
+  [nominalTypeHack]?: T;
+>[nominalTypeHack] : T | undefined
+>nominalTypeHack : unique symbol
+}
+type WeakValidationMap<T> = {
+>WeakValidationMap : WeakValidationMap<T>
+
+  [K in keyof T]?: null extends T[K]
+>null : null
+
+    ? Validator<T[K] | null | undefined>
+>null : null
+
+    : undefined extends T[K]
+    ? Validator<T[K] | null | undefined>
+>null : null
+
+    : Validator<T[K]>
+};
+type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
+>ComponentType : ComponentType<P>
+
+type Shared<
+>Shared : Shared<InjectedProps, DecorationTargetProps>
+
+  InjectedProps,
+  DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
+> = {
+  [P in Extract<
+    keyof InjectedProps,
+    keyof DecorationTargetProps
+  >]?: InjectedProps[P] extends DecorationTargetProps[P]
+    ? DecorationTargetProps[P]
+    : never
+};
+
+// Infers prop type from component C
+type GetProps<C> = C extends ComponentType<infer P> ? P : never;
+>GetProps : GetProps<C>
+
+type ConnectedComponentClass<C extends ComponentType<any>, P> = ComponentClass<
+>ConnectedComponentClass : ConnectedComponentClass<C, P>
+
+  P
+> & {
+  WrappedComponent: C;
+>WrappedComponent : C
+
+};
+
+type Matching<InjectedProps, DecorationTargetProps> = {
+>Matching : Matching<InjectedProps, DecorationTargetProps>
+
+  [P in keyof DecorationTargetProps]: P extends keyof InjectedProps
+    ? InjectedProps[P] extends DecorationTargetProps[P]
+      ? DecorationTargetProps[P]
+      : InjectedProps[P]
+    : DecorationTargetProps[P]
+};
+
+type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
+>Omit : Pick<T, Exclude<keyof T, K>>
+
+type InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> = <
+>InferableComponentEnhancerWithProps : InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps>
+
+  C extends ComponentType<Matching<TInjectedProps, GetProps<C>>>
+>(
+  component: C
+>component : C
+
+) => ConnectedComponentClass<
+  C,
+  Omit<GetProps<C>, keyof Shared<TInjectedProps, GetProps<C>>> & TNeedsProps
+>;
+
+declare const connect: {
+>connect : <no_state = {}, TDispatchProps = {}, TOwnProps = {}>(mapStateToProps: null | undefined, mapDispatchToProps: TDispatchProps) => InferableComponentEnhancerWithProps<ResolveThunks<TDispatchProps>, TOwnProps>
+
+  <no_state = {}, TDispatchProps = {}, TOwnProps = {}>(
+    mapStateToProps: null | undefined,
+>mapStateToProps : null | undefined
+>null : null
+
+    mapDispatchToProps: TDispatchProps
+>mapDispatchToProps : TDispatchProps
+
+  ): InferableComponentEnhancerWithProps<
+    ResolveThunks<TDispatchProps>,
+    TOwnProps
+  >;
+};
+
+type InferThunkActionCreatorType<
+>InferThunkActionCreatorType : InferThunkActionCreatorType<TActionCreator>
+
+  TActionCreator extends (...args: any[]) => any
+>args : any[]
+
+> = TActionCreator extends (
+  ...args: infer TParams
+>args : TParams
+
+) => (...args: any[]) => infer TReturn
+>args : any[]
+
+  ? (...args: TParams) => TReturn
+>args : TParams
+
+  : TActionCreator;
+
+type HandleThunkActionCreator<TActionCreator> = TActionCreator extends (
+>HandleThunkActionCreator : HandleThunkActionCreator<TActionCreator>
+
+  ...args: any[]
+>args : any[]
+
+) => any
+  ? InferThunkActionCreatorType<TActionCreator>
+  : TActionCreator;
+
+type ResolveThunks<TDispatchProps> = TDispatchProps extends {
+>ResolveThunks : ResolveThunks<TDispatchProps>
+
+  [key: string]: any;
+>key : string
+}
+  ? { [C in keyof TDispatchProps]: HandleThunkActionCreator<TDispatchProps[C]> }
+  : TDispatchProps;
+
+interface Dispatch<A extends Action = AnyAction> {
+  <T extends A>(action: T): T;
+>action : T
+}
+interface Action<T = any> {
+  type: T;
+>type : T
+}
+interface AnyAction extends Action {
+  [extraProps: string]: any;
+>extraProps : string
+}
+
+const simpleAction = (payload: boolean) => ({
+>simpleAction : (payload: boolean) => { type: string; payload: boolean; }
+>(payload: boolean) => ({  type: "SIMPLE_ACTION",  payload}) : (payload: boolean) => { type: string; payload: boolean; }
+>payload : boolean
+>({  type: "SIMPLE_ACTION",  payload}) : { type: string; payload: boolean; }
+>{  type: "SIMPLE_ACTION",  payload} : { type: string; payload: boolean; }
+
+  type: "SIMPLE_ACTION",
+>type : string
+>"SIMPLE_ACTION" : "SIMPLE_ACTION"
+
+  payload
+>payload : boolean
+
+});
+const thunkAction = (param1: number, param2: string) => async (
+>thunkAction : (param1: number, param2: string) => (dispatch: Dispatch<AnyAction>, { foo }: OwnProps) => Promise<string>
+>(param1: number, param2: string) => async (  dispatch: Dispatch,  { foo }: OwnProps) => {  return foo;} : (param1: number, param2: string) => (dispatch: Dispatch<AnyAction>, { foo }: OwnProps) => Promise<string>
+>param1 : number
+>param2 : string
+>async (  dispatch: Dispatch,  { foo }: OwnProps) => {  return foo;} : (dispatch: Dispatch<AnyAction>, { foo }: OwnProps) => Promise<string>
+
+  dispatch: Dispatch,
+>dispatch : Dispatch<AnyAction>
+
+  { foo }: OwnProps
+>foo : string
+
+) => {
+  return foo;
+>foo : string
+
+};
+interface OwnProps {
+  foo: string;
+>foo : string
+}
+interface TestComponentProps extends OwnProps {
+  simpleAction: typeof simpleAction;
+>simpleAction : (payload: boolean) => { type: string; payload: boolean; }
+>simpleAction : (payload: boolean) => { type: string; payload: boolean; }
+
+  thunkAction(param1: number, param2: string): Promise<string>;
+>thunkAction : (param1: number, param2: string) => Promise<string>
+>param1 : number
+>param2 : string
+}
+class TestComponent extends Component<TestComponentProps> {}
+>TestComponent : TestComponent
+>Component : Component<TestComponentProps>
+
+const mapDispatchToProps = { simpleAction, thunkAction };
+>mapDispatchToProps : { simpleAction: (payload: boolean) => { type: string; payload: boolean; }; thunkAction: (param1: number, param2: string) => (dispatch: Dispatch<AnyAction>, { foo }: OwnProps) => Promise<string>; }
+>{ simpleAction, thunkAction } : { simpleAction: (payload: boolean) => { type: string; payload: boolean; }; thunkAction: (param1: number, param2: string) => (dispatch: Dispatch<AnyAction>, { foo }: OwnProps) => Promise<string>; }
+>simpleAction : (payload: boolean) => { type: string; payload: boolean; }
+>thunkAction : (param1: number, param2: string) => (dispatch: Dispatch<AnyAction>, { foo }: OwnProps) => Promise<string>
+
+type Q = HandleThunkActionCreator<typeof simpleAction>;
+>Q : (payload: boolean) => { type: string; payload: boolean; }
+>simpleAction : (payload: boolean) => { type: string; payload: boolean; }
+
+const Test1 = connect(
+>Test1 : ConnectedComponentClass<typeof TestComponent, Pick<TestComponentProps, "foo">>
+>connect(  null,  mapDispatchToProps)(TestComponent) : ConnectedComponentClass<typeof TestComponent, Pick<TestComponentProps, "foo">>
+>connect(  null,  mapDispatchToProps) : InferableComponentEnhancerWithProps<{ simpleAction: (payload: boolean) => { type: string; payload: boolean; }; thunkAction: (param1: number, param2: string) => Promise<string>; }, {}>
+>connect : <no_state = {}, TDispatchProps = {}, TOwnProps = {}>(mapStateToProps: null | undefined, mapDispatchToProps: TDispatchProps) => InferableComponentEnhancerWithProps<ResolveThunks<TDispatchProps>, TOwnProps>
+
+  null,
+>null : null
+
+  mapDispatchToProps
+>mapDispatchToProps : { simpleAction: (payload: boolean) => { type: string; payload: boolean; }; thunkAction: (param1: number, param2: string) => (dispatch: Dispatch<AnyAction>, { foo }: OwnProps) => Promise<string>; }
+
+)(TestComponent);
+>TestComponent : typeof TestComponent
+
diff --git a/tests/cases/compiler/reactReduxLikeDeferredInferenceAllowsAssignment.ts b/tests/cases/compiler/reactReduxLikeDeferredInferenceAllowsAssignment.ts
new file mode 100644
index 0000000000000..940031c52c2e0
--- /dev/null
+++ b/tests/cases/compiler/reactReduxLikeDeferredInferenceAllowsAssignment.ts
@@ -0,0 +1,145 @@
+// @strict: true
+declare class Component<P> {
+  constructor(props: Readonly<P>);
+  constructor(props: P, context?: any);
+  readonly props: Readonly<P> & Readonly<{ children?: {} }>;
+}
+interface ComponentClass<P = {}> {
+  new (props: P, context?: any): Component<P>;
+  propTypes?: WeakValidationMap<P>;
+  defaultProps?: Partial<P>;
+  displayName?: string;
+}
+interface FunctionComponent<P = {}> {
+  (props: P & { children?: {} }, context?: any): {} | null;
+  propTypes?: WeakValidationMap<P>;
+  defaultProps?: Partial<P>;
+  displayName?: string;
+}
+
+declare const nominalTypeHack: unique symbol;
+interface Validator<T> {
+  (
+    props: object,
+    propName: string,
+    componentName: string,
+    location: string,
+    propFullName: string
+  ): Error | null;
+  [nominalTypeHack]?: T;
+}
+type WeakValidationMap<T> = {
+  [K in keyof T]?: null extends T[K]
+    ? Validator<T[K] | null | undefined>
+    : undefined extends T[K]
+    ? Validator<T[K] | null | undefined>
+    : Validator<T[K]>
+};
+type ComponentType<P = {}> = ComponentClass<P> | FunctionComponent<P>;
+
+type Shared<
+  InjectedProps,
+  DecorationTargetProps extends Shared<InjectedProps, DecorationTargetProps>
+> = {
+  [P in Extract<
+    keyof InjectedProps,
+    keyof DecorationTargetProps
+  >]?: InjectedProps[P] extends DecorationTargetProps[P]
+    ? DecorationTargetProps[P]
+    : never
+};
+
+// Infers prop type from component C
+type GetProps<C> = C extends ComponentType<infer P> ? P : never;
+
+type ConnectedComponentClass<C extends ComponentType<any>, P> = ComponentClass<
+  P
+> & {
+  WrappedComponent: C;
+};
+
+type Matching<InjectedProps, DecorationTargetProps> = {
+  [P in keyof DecorationTargetProps]: P extends keyof InjectedProps
+    ? InjectedProps[P] extends DecorationTargetProps[P]
+      ? DecorationTargetProps[P]
+      : InjectedProps[P]
+    : DecorationTargetProps[P]
+};
+
+type Omit<T, K extends keyof T> = Pick<T, Exclude<keyof T, K>>;
+
+type InferableComponentEnhancerWithProps<TInjectedProps, TNeedsProps> = <
+  C extends ComponentType<Matching<TInjectedProps, GetProps<C>>>
+>(
+  component: C
+) => ConnectedComponentClass<
+  C,
+  Omit<GetProps<C>, keyof Shared<TInjectedProps, GetProps<C>>> & TNeedsProps
+>;
+
+declare const connect: {
+  <no_state = {}, TDispatchProps = {}, TOwnProps = {}>(
+    mapStateToProps: null | undefined,
+    mapDispatchToProps: TDispatchProps
+  ): InferableComponentEnhancerWithProps<
+    ResolveThunks<TDispatchProps>,
+    TOwnProps
+  >;
+};
+
+type InferThunkActionCreatorType<
+  TActionCreator extends (...args: any[]) => any
+> = TActionCreator extends (
+  ...args: infer TParams
+) => (...args: any[]) => infer TReturn
+  ? (...args: TParams) => TReturn
+  : TActionCreator;
+
+type HandleThunkActionCreator<TActionCreator> = TActionCreator extends (
+  ...args: any[]
+) => any
+  ? InferThunkActionCreatorType<TActionCreator>
+  : TActionCreator;
+
+type ResolveThunks<TDispatchProps> = TDispatchProps extends {
+  [key: string]: any;
+}
+  ? { [C in keyof TDispatchProps]: HandleThunkActionCreator<TDispatchProps[C]> }
+  : TDispatchProps;
+
+interface Dispatch<A extends Action = AnyAction> {
+  <T extends A>(action: T): T;
+}
+interface Action<T = any> {
+  type: T;
+}
+interface AnyAction extends Action {
+  [extraProps: string]: any;
+}
+
+const simpleAction = (payload: boolean) => ({
+  type: "SIMPLE_ACTION",
+  payload
+});
+const thunkAction = (param1: number, param2: string) => async (
+  dispatch: Dispatch,
+  { foo }: OwnProps
+) => {
+  return foo;
+};
+interface OwnProps {
+  foo: string;
+}
+interface TestComponentProps extends OwnProps {
+  simpleAction: typeof simpleAction;
+  thunkAction(param1: number, param2: string): Promise<string>;
+}
+class TestComponent extends Component<TestComponentProps> {}
+const mapDispatchToProps = { simpleAction, thunkAction };
+
+type Q = HandleThunkActionCreator<typeof simpleAction>;
+
+const Test1 = connect(
+  null,
+  mapDispatchToProps
+)(TestComponent);

From 34cc42758e1942efc54118b88be58dcf9a5a112f Mon Sep 17 00:00:00 2001
From: Wesley Wigham <wewigham@microsoft.com>
Date: Wed, 27 Mar 2019 10:50:11 -0700
Subject: [PATCH 5/5] Allow tuple expansions to an `any` rest to be considered
 an `any` signature as well

---
 src/compiler/checker.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 34391510b343a..98a459b6ccd3d 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -11734,7 +11734,7 @@ namespace ts {
          */
         function isAnySignature(s: Signature) {
             return !s.typeParameters && (!s.thisParameter || isTypeAny(getTypeOfParameter(s.thisParameter))) && s.parameters.length === 1 &&
-                s.hasRestParameter && getTypeOfParameter(s.parameters[0]) === anyArrayType &&
+                s.hasRestParameter && (getTypeOfParameter(s.parameters[0]) === anyArrayType || isTypeAny(getTypeOfParameter(s.parameters[0]))) &&
                 isTypeAny(getReturnTypeOfSignature(s));
         }