diff --git a/src/compiler/binder.ts b/src/compiler/binder.ts
index 6bd6045a55101..ee07acdac8299 100644
--- a/src/compiler/binder.ts
+++ b/src/compiler/binder.ts
@@ -856,9 +856,8 @@ namespace ts {
         function isNarrowableReference(expr: Expression): boolean {
             return expr.kind === SyntaxKind.Identifier || expr.kind === SyntaxKind.ThisKeyword || expr.kind === SyntaxKind.SuperKeyword ||
                 (isPropertyAccessExpression(expr) || isNonNullExpression(expr) || isParenthesizedExpression(expr)) && isNarrowableReference(expr.expression) ||
-                isElementAccessExpression(expr) &&
-                isStringOrNumericLiteralLike(expr.argumentExpression) &&
-                isNarrowableReference(expr.expression);
+                isElementAccessExpression(expr) && isStringOrNumericLiteralLike(expr.argumentExpression) && isNarrowableReference(expr.expression) ||
+                isOptionalChain(expr);
         }
 
         function hasNarrowableArgument(expr: CallExpression) {
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 6ece23f022ab3..a759f7179b1a7 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -18124,6 +18124,16 @@ namespace ts {
             return false;
         }
 
+        function optionalChainContainsReference(source: Node, target: Node) {
+            while (isOptionalChain(source)) {
+                source = source.expression;
+                if (isMatchingReference(source, target)) {
+                    return true;
+                }
+            }
+            return false;
+        }
+
         // Return true if target is a property access xxx.yyy, source is a property access xxx.zzz, the declared
         // type of xxx is a union type, and yyy is a property that is possibly a discriminant. We consider a property
         // a possible discriminant if its type differs in the constituents of containing union type, and if every
@@ -19350,6 +19360,14 @@ namespace ts {
                         if (isMatchingReference(reference, right)) {
                             return narrowTypeByEquality(type, operator, left, assumeTrue);
                         }
+                        if (assumeTrue && strictNullChecks) {
+                            if (optionalChainContainsReference(left, reference)) {
+                                type = narrowTypeByOptionalChainContainment(type, operator, right);
+                            }
+                            else if (optionalChainContainsReference(right, reference)) {
+                                type = narrowTypeByOptionalChainContainment(type, operator, left);
+                            }
+                        }
                         if (isMatchingReferenceDiscriminant(left, declaredType)) {
                             return narrowTypeByDiscriminant(type, <AccessExpression>left, t => narrowTypeByEquality(t, operator, right, assumeTrue));
                         }
@@ -19374,6 +19392,18 @@ namespace ts {
                 return type;
             }
 
+            function narrowTypeByOptionalChainContainment(type: Type, operator: SyntaxKind, value: Expression): Type {
+                // We are in the true branch of obj?.foo === value or obj?.foo !== value. We remove undefined and null from
+                // the type of obj if (a) the operator is === and the type of value doesn't include undefined or (b) the
+                // operator is !== and the type of value is undefined.
+                const valueType = getTypeOfExpression(value);
+                return operator === SyntaxKind.EqualsEqualsToken && !(getTypeFacts(valueType) & TypeFacts.EQUndefinedOrNull) ||
+                    operator === SyntaxKind.EqualsEqualsEqualsToken && !(getTypeFacts(valueType) & TypeFacts.EQUndefined) ||
+                    operator === SyntaxKind.ExclamationEqualsToken && valueType.flags & TypeFlags.Nullable ||
+                    operator === SyntaxKind.ExclamationEqualsEqualsToken && valueType.flags & TypeFlags.Undefined ?
+                    getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull) : type;
+            }
+
             function narrowTypeByEquality(type: Type, operator: SyntaxKind, value: Expression, assumeTrue: boolean): Type {
                 if (type.flags & TypeFlags.Any) {
                     return type;
@@ -19424,6 +19454,10 @@ namespace ts {
                 // We have '==', '!=', '===', or !==' operator with 'typeof xxx' and string literal operands
                 const target = getReferenceCandidate(typeOfExpr.expression);
                 if (!isMatchingReference(reference, target)) {
+                    if (assumeTrue && (operator === SyntaxKind.EqualsEqualsToken || operator === SyntaxKind.EqualsEqualsEqualsToken) &&
+                        strictNullChecks && optionalChainContainsReference(target, reference)) {
+                        return getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull);
+                    }
                     // For a reference of the form 'x.y', a 'typeof x === ...' type guard resets the
                     // narrowed type of 'y' to its declared type.
                     if (containsMatchingReference(reference, target)) {
@@ -19605,6 +19639,9 @@ namespace ts {
             function narrowTypeByInstanceof(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
                 const left = getReferenceCandidate(expr.left);
                 if (!isMatchingReference(reference, left)) {
+                    if (assumeTrue && strictNullChecks && optionalChainContainsReference(left, reference)) {
+                        return getTypeWithFacts(type, TypeFacts.NEUndefinedOrNull);
+                    }
                     // For a reference of the form 'x.y', an 'x instanceof T' type guard resets the
                     // narrowed type of 'y' to its declared type. We do this because preceding 'x.y'
                     // references might reference a different 'y' property. However, we make an exception
diff --git a/tests/baselines/reference/controlFlowOptionalChain.errors.txt b/tests/baselines/reference/controlFlowOptionalChain.errors.txt
index ce46b232b3d81..987dca335dccc 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.errors.txt
+++ b/tests/baselines/reference/controlFlowOptionalChain.errors.txt
@@ -6,7 +6,6 @@ tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(35,5): error TS2
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(39,1): error TS2722: Cannot invoke an object which is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(52,5): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(57,1): error TS2532: Object is possibly 'undefined'.
-tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(62,5): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(68,5): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(72,1): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(83,5): error TS2532: Object is possibly 'undefined'.
@@ -20,9 +19,21 @@ tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(112,1): error TS
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(130,5): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(134,1): error TS2532: Object is possibly 'undefined'.
 tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(153,9): error TS2775: Assertions require every name in the call target to be declared with an explicit type annotation.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(208,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(211,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(214,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(217,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(220,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(223,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(238,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(241,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(244,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(271,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(274,9): error TS2532: Object is possibly 'undefined'.
+tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(277,9): error TS2532: Object is possibly 'undefined'.
 
 
-==== tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts (22 errors) ====
+==== tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts (33 errors) ====
     // assignments in shortcutting chain
     declare const o: undefined | {
         [key: string]: any;
@@ -99,10 +110,8 @@ tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(153,9): error TS
     
     declare const o3: { x: 1, y: string } | { x: 2, y: number } | undefined;
     if (o3?.x === 1) {
-        o3; // TODO: should be `{ x: y, y: string }`
-        o3.x; // TODO: should not be an error.
-        ~~
-!!! error TS2532: Object is possibly 'undefined'.
+        o3;
+        o3.x;
         o3?.x;
     }
     else {
@@ -227,4 +236,198 @@ tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts(153,9): error TS
             x;
         }
     }
+    
+    type Thing = { foo: string | number, bar(): number, baz: object };
+    
+    function f10(o: Thing | undefined, value: number) {
+        if (o?.foo === value) {
+            o.foo;
+        }
+        if (o?.["foo"] === value) {
+            o["foo"];
+        }
+        if (o?.bar() === value) {
+            o.bar;
+        }
+        if (o?.foo == value) {
+            o.foo;
+        }
+        if (o?.["foo"] == value) {
+            o["foo"];
+        }
+        if (o?.bar() == value) {
+            o.bar;
+        }
+    }
+    
+    function f11(o: Thing | null, value: number) {
+        if (o?.foo === value) {
+            o.foo;
+        }
+        if (o?.["foo"] === value) {
+            o["foo"];
+        }
+        if (o?.bar() === value) {
+            o.bar;
+        }
+        if (o?.foo == value) {
+            o.foo;
+        }
+        if (o?.["foo"] == value) {
+            o["foo"];
+        }
+        if (o?.bar() == value) {
+            o.bar;
+        }
+    }
+    
+    function f12(o: Thing | undefined, value: number | undefined) {
+        if (o?.foo === value) {
+            o.foo;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.["foo"] === value) {
+            o["foo"];  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.bar() === value) {
+            o.bar;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.foo == value) {
+            o.foo;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.["foo"] == value) {
+            o["foo"];  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.bar() == value) {
+            o.bar;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+    }
+    
+    function f12a(o: Thing | undefined, value: number | null) {
+        if (o?.foo === value) {
+            o.foo;
+        }
+        if (o?.["foo"] === value) {
+            o["foo"];
+        }
+        if (o?.bar() === value) {
+            o.bar;
+        }
+        if (o?.foo == value) {
+            o.foo;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.["foo"] == value) {
+            o["foo"];  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.bar() == value) {
+            o.bar;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+    }
+    
+    function f13(o: Thing | undefined) {
+        if (o?.foo !== undefined) {
+            o.foo;
+        }
+        if (o?.["foo"] !== undefined) {
+            o["foo"];
+        }
+        if (o?.bar() !== undefined) {
+            o.bar;
+        }
+        if (o?.foo != undefined) {
+            o.foo;
+        }
+        if (o?.["foo"] != undefined) {
+            o["foo"];
+        }
+        if (o?.bar() != undefined) {
+            o.bar;
+        }
+    }
+    
+    function f13a(o: Thing | undefined) {
+        if (o?.foo !== null) {
+            o.foo;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.["foo"] !== null) {
+            o["foo"];  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.bar() !== null) {
+            o.bar;  // Error
+            ~
+!!! error TS2532: Object is possibly 'undefined'.
+        }
+        if (o?.foo != null) {
+            o.foo;
+        }
+        if (o?.["foo"] != null) {
+            o["foo"];
+        }
+        if (o?.bar() != null) {
+            o.bar;
+        }
+    }
+    
+    function f14(o: Thing | null) {
+        if (o?.foo !== undefined) {
+            o.foo;
+        }
+        if (o?.["foo"] !== undefined) {
+            o["foo"];
+        }
+        if (o?.bar() !== undefined) {
+            o.bar;
+        }
+    }
+    
+    function f20(o: Thing | undefined) {
+        if (typeof o?.foo === "number") {
+            o.foo;
+        }
+        if (typeof o?.["foo"] === "number") {
+            o["foo"];
+        }
+        if (typeof o?.bar() === "number") {
+            o.bar;
+        }
+        if (o?.baz instanceof Error) {
+            o.baz;
+        }
+    }
+    
+    function f21(o: Thing | null) {
+        if (typeof o?.foo === "number") {
+            o.foo;
+        }
+        if (typeof o?.["foo"] === "number") {
+            o["foo"];
+        }
+        if (typeof o?.bar() === "number") {
+            o.bar;
+        }
+        if (o?.baz instanceof Error) {
+            o.baz;
+        }
+    }
     
\ No newline at end of file
diff --git a/tests/baselines/reference/controlFlowOptionalChain.js b/tests/baselines/reference/controlFlowOptionalChain.js
index 58a2873f93aa1..214515280350b 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.js
+++ b/tests/baselines/reference/controlFlowOptionalChain.js
@@ -59,8 +59,8 @@ o2.f;
 
 declare const o3: { x: 1, y: string } | { x: 2, y: number } | undefined;
 if (o3?.x === 1) {
-    o3; // TODO: should be `{ x: y, y: string }`
-    o3.x; // TODO: should not be an error.
+    o3;
+    o3.x;
     o3?.x;
 }
 else {
@@ -159,6 +159,176 @@ function f01(x: unknown) {
         x;
     }
 }
+
+type Thing = { foo: string | number, bar(): number, baz: object };
+
+function f10(o: Thing | undefined, value: number) {
+    if (o?.foo === value) {
+        o.foo;
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];
+    }
+    if (o?.bar() === value) {
+        o.bar;
+    }
+    if (o?.foo == value) {
+        o.foo;
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];
+    }
+    if (o?.bar() == value) {
+        o.bar;
+    }
+}
+
+function f11(o: Thing | null, value: number) {
+    if (o?.foo === value) {
+        o.foo;
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];
+    }
+    if (o?.bar() === value) {
+        o.bar;
+    }
+    if (o?.foo == value) {
+        o.foo;
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];
+    }
+    if (o?.bar() == value) {
+        o.bar;
+    }
+}
+
+function f12(o: Thing | undefined, value: number | undefined) {
+    if (o?.foo === value) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() === value) {
+        o.bar;  // Error
+    }
+    if (o?.foo == value) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() == value) {
+        o.bar;  // Error
+    }
+}
+
+function f12a(o: Thing | undefined, value: number | null) {
+    if (o?.foo === value) {
+        o.foo;
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];
+    }
+    if (o?.bar() === value) {
+        o.bar;
+    }
+    if (o?.foo == value) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() == value) {
+        o.bar;  // Error
+    }
+}
+
+function f13(o: Thing | undefined) {
+    if (o?.foo !== undefined) {
+        o.foo;
+    }
+    if (o?.["foo"] !== undefined) {
+        o["foo"];
+    }
+    if (o?.bar() !== undefined) {
+        o.bar;
+    }
+    if (o?.foo != undefined) {
+        o.foo;
+    }
+    if (o?.["foo"] != undefined) {
+        o["foo"];
+    }
+    if (o?.bar() != undefined) {
+        o.bar;
+    }
+}
+
+function f13a(o: Thing | undefined) {
+    if (o?.foo !== null) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] !== null) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() !== null) {
+        o.bar;  // Error
+    }
+    if (o?.foo != null) {
+        o.foo;
+    }
+    if (o?.["foo"] != null) {
+        o["foo"];
+    }
+    if (o?.bar() != null) {
+        o.bar;
+    }
+}
+
+function f14(o: Thing | null) {
+    if (o?.foo !== undefined) {
+        o.foo;
+    }
+    if (o?.["foo"] !== undefined) {
+        o["foo"];
+    }
+    if (o?.bar() !== undefined) {
+        o.bar;
+    }
+}
+
+function f20(o: Thing | undefined) {
+    if (typeof o?.foo === "number") {
+        o.foo;
+    }
+    if (typeof o?.["foo"] === "number") {
+        o["foo"];
+    }
+    if (typeof o?.bar() === "number") {
+        o.bar;
+    }
+    if (o?.baz instanceof Error) {
+        o.baz;
+    }
+}
+
+function f21(o: Thing | null) {
+    if (typeof o?.foo === "number") {
+        o.foo;
+    }
+    if (typeof o?.["foo"] === "number") {
+        o["foo"];
+    }
+    if (typeof o?.bar() === "number") {
+        o.bar;
+    }
+    if (o?.baz instanceof Error) {
+        o.baz;
+    }
+}
 
 
 //// [controlFlowOptionalChain.js]
@@ -206,8 +376,8 @@ o2;
 (_k = o2) === null || _k === void 0 ? void 0 : _k.f;
 o2.f;
 if (((_l = o3) === null || _l === void 0 ? void 0 : _l.x) === 1) {
-    o3; // TODO: should be `{ x: y, y: string }`
-    o3.x; // TODO: should not be an error.
+    o3;
+    o3.x;
     (_m = o3) === null || _m === void 0 ? void 0 : _m.x;
 }
 else {
@@ -286,3 +456,171 @@ function f01(x) {
         x;
     }
 }
+function f10(o, value) {
+    var _a, _b, _c, _d, _e, _f;
+    if (((_a = o) === null || _a === void 0 ? void 0 : _a.foo) === value) {
+        o.foo;
+    }
+    if (((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) === value) {
+        o["foo"];
+    }
+    if (((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) === value) {
+        o.bar;
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.foo) == value) {
+        o.foo;
+    }
+    if (((_e = o) === null || _e === void 0 ? void 0 : _e["foo"]) == value) {
+        o["foo"];
+    }
+    if (((_f = o) === null || _f === void 0 ? void 0 : _f.bar()) == value) {
+        o.bar;
+    }
+}
+function f11(o, value) {
+    var _a, _b, _c, _d, _e, _f;
+    if (((_a = o) === null || _a === void 0 ? void 0 : _a.foo) === value) {
+        o.foo;
+    }
+    if (((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) === value) {
+        o["foo"];
+    }
+    if (((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) === value) {
+        o.bar;
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.foo) == value) {
+        o.foo;
+    }
+    if (((_e = o) === null || _e === void 0 ? void 0 : _e["foo"]) == value) {
+        o["foo"];
+    }
+    if (((_f = o) === null || _f === void 0 ? void 0 : _f.bar()) == value) {
+        o.bar;
+    }
+}
+function f12(o, value) {
+    var _a, _b, _c, _d, _e, _f;
+    if (((_a = o) === null || _a === void 0 ? void 0 : _a.foo) === value) {
+        o.foo; // Error
+    }
+    if (((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) === value) {
+        o["foo"]; // Error
+    }
+    if (((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) === value) {
+        o.bar; // Error
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.foo) == value) {
+        o.foo; // Error
+    }
+    if (((_e = o) === null || _e === void 0 ? void 0 : _e["foo"]) == value) {
+        o["foo"]; // Error
+    }
+    if (((_f = o) === null || _f === void 0 ? void 0 : _f.bar()) == value) {
+        o.bar; // Error
+    }
+}
+function f12a(o, value) {
+    var _a, _b, _c, _d, _e, _f;
+    if (((_a = o) === null || _a === void 0 ? void 0 : _a.foo) === value) {
+        o.foo;
+    }
+    if (((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) === value) {
+        o["foo"];
+    }
+    if (((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) === value) {
+        o.bar;
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.foo) == value) {
+        o.foo; // Error
+    }
+    if (((_e = o) === null || _e === void 0 ? void 0 : _e["foo"]) == value) {
+        o["foo"]; // Error
+    }
+    if (((_f = o) === null || _f === void 0 ? void 0 : _f.bar()) == value) {
+        o.bar; // Error
+    }
+}
+function f13(o) {
+    var _a, _b, _c, _d, _e, _f;
+    if (((_a = o) === null || _a === void 0 ? void 0 : _a.foo) !== undefined) {
+        o.foo;
+    }
+    if (((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) !== undefined) {
+        o["foo"];
+    }
+    if (((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) !== undefined) {
+        o.bar;
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.foo) != undefined) {
+        o.foo;
+    }
+    if (((_e = o) === null || _e === void 0 ? void 0 : _e["foo"]) != undefined) {
+        o["foo"];
+    }
+    if (((_f = o) === null || _f === void 0 ? void 0 : _f.bar()) != undefined) {
+        o.bar;
+    }
+}
+function f13a(o) {
+    var _a, _b, _c, _d, _e, _f;
+    if (((_a = o) === null || _a === void 0 ? void 0 : _a.foo) !== null) {
+        o.foo; // Error
+    }
+    if (((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) !== null) {
+        o["foo"]; // Error
+    }
+    if (((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) !== null) {
+        o.bar; // Error
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.foo) != null) {
+        o.foo;
+    }
+    if (((_e = o) === null || _e === void 0 ? void 0 : _e["foo"]) != null) {
+        o["foo"];
+    }
+    if (((_f = o) === null || _f === void 0 ? void 0 : _f.bar()) != null) {
+        o.bar;
+    }
+}
+function f14(o) {
+    var _a, _b, _c;
+    if (((_a = o) === null || _a === void 0 ? void 0 : _a.foo) !== undefined) {
+        o.foo;
+    }
+    if (((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) !== undefined) {
+        o["foo"];
+    }
+    if (((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) !== undefined) {
+        o.bar;
+    }
+}
+function f20(o) {
+    var _a, _b, _c, _d;
+    if (typeof ((_a = o) === null || _a === void 0 ? void 0 : _a.foo) === "number") {
+        o.foo;
+    }
+    if (typeof ((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) === "number") {
+        o["foo"];
+    }
+    if (typeof ((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) === "number") {
+        o.bar;
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.baz) instanceof Error) {
+        o.baz;
+    }
+}
+function f21(o) {
+    var _a, _b, _c, _d;
+    if (typeof ((_a = o) === null || _a === void 0 ? void 0 : _a.foo) === "number") {
+        o.foo;
+    }
+    if (typeof ((_b = o) === null || _b === void 0 ? void 0 : _b["foo"]) === "number") {
+        o["foo"];
+    }
+    if (typeof ((_c = o) === null || _c === void 0 ? void 0 : _c.bar()) === "number") {
+        o.bar;
+    }
+    if (((_d = o) === null || _d === void 0 ? void 0 : _d.baz) instanceof Error) {
+        o.baz;
+    }
+}
diff --git a/tests/baselines/reference/controlFlowOptionalChain.symbols b/tests/baselines/reference/controlFlowOptionalChain.symbols
index 21f1de2a41026..2665a960a568a 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.symbols
+++ b/tests/baselines/reference/controlFlowOptionalChain.symbols
@@ -182,18 +182,18 @@ if (o3?.x === 1) {
 >o3 : Symbol(o3, Decl(controlFlowOptionalChain.ts, 58, 13))
 >x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19), Decl(controlFlowOptionalChain.ts, 58, 41))
 
-    o3; // TODO: should be `{ x: y, y: string }`
+    o3;
 >o3 : Symbol(o3, Decl(controlFlowOptionalChain.ts, 58, 13))
 
-    o3.x; // TODO: should not be an error.
->o3.x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19), Decl(controlFlowOptionalChain.ts, 58, 41))
+    o3.x;
+>o3.x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19))
 >o3 : Symbol(o3, Decl(controlFlowOptionalChain.ts, 58, 13))
->x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19), Decl(controlFlowOptionalChain.ts, 58, 41))
+>x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19))
 
     o3?.x;
->o3?.x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19), Decl(controlFlowOptionalChain.ts, 58, 41))
+>o3?.x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19))
 >o3 : Symbol(o3, Decl(controlFlowOptionalChain.ts, 58, 13))
->x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19), Decl(controlFlowOptionalChain.ts, 58, 41))
+>x : Symbol(x, Decl(controlFlowOptionalChain.ts, 58, 19))
 }
 else {
     o3;
@@ -600,3 +600,532 @@ function f01(x: unknown) {
     }
 }
 
+type Thing = { foo: string | number, bar(): number, baz: object };
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+
+function f10(o: Thing | undefined, value: number) {
+>f10 : Symbol(f10, Decl(controlFlowOptionalChain.ts, 161, 66))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 163, 34))
+
+    if (o?.foo === value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 163, 34))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] === value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 163, 34))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() === value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 163, 34))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.foo == value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 163, 34))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] == value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 163, 34))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() == value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 163, 34))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 163, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+}
+
+function f11(o: Thing | null, value: number) {
+>f11 : Symbol(f11, Decl(controlFlowOptionalChain.ts, 182, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 184, 29))
+
+    if (o?.foo === value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 184, 29))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] === value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 184, 29))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() === value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 184, 29))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.foo == value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 184, 29))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] == value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 184, 29))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() == value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 184, 29))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 184, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+}
+
+function f12(o: Thing | undefined, value: number | undefined) {
+>f12 : Symbol(f12, Decl(controlFlowOptionalChain.ts, 203, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 205, 34))
+
+    if (o?.foo === value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 205, 34))
+
+        o.foo;  // Error
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] === value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 205, 34))
+
+        o["foo"];  // Error
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+    }
+    if (o?.bar() === value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 205, 34))
+
+        o.bar;  // Error
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.foo == value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 205, 34))
+
+        o.foo;  // Error
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] == value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 205, 34))
+
+        o["foo"];  // Error
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+    }
+    if (o?.bar() == value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 205, 34))
+
+        o.bar;  // Error
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 205, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+}
+
+function f12a(o: Thing | undefined, value: number | null) {
+>f12a : Symbol(f12a, Decl(controlFlowOptionalChain.ts, 224, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 226, 35))
+
+    if (o?.foo === value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 226, 35))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] === value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 226, 35))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() === value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 226, 35))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.foo == value) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 226, 35))
+
+        o.foo;  // Error
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] == value) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 226, 35))
+
+        o["foo"];  // Error
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+    }
+    if (o?.bar() == value) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>value : Symbol(value, Decl(controlFlowOptionalChain.ts, 226, 35))
+
+        o.bar;  // Error
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 226, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+}
+
+function f13(o: Thing | undefined) {
+>f13 : Symbol(f13, Decl(controlFlowOptionalChain.ts, 245, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+
+    if (o?.foo !== undefined) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>undefined : Symbol(undefined)
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] !== undefined) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>undefined : Symbol(undefined)
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() !== undefined) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>undefined : Symbol(undefined)
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.foo != undefined) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>undefined : Symbol(undefined)
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] != undefined) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>undefined : Symbol(undefined)
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() != undefined) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>undefined : Symbol(undefined)
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 247, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+}
+
+function f13a(o: Thing | undefined) {
+>f13a : Symbol(f13a, Decl(controlFlowOptionalChain.ts, 266, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+
+    if (o?.foo !== null) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+
+        o.foo;  // Error
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] !== null) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+
+        o["foo"];  // Error
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+    }
+    if (o?.bar() !== null) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+
+        o.bar;  // Error
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.foo != null) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] != null) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() != null) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 268, 14))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+}
+
+function f14(o: Thing | null) {
+>f14 : Symbol(f14, Decl(controlFlowOptionalChain.ts, 287, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 289, 13))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+
+    if (o?.foo !== undefined) {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 289, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>undefined : Symbol(undefined)
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 289, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.["foo"] !== undefined) {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 289, 13))
+>undefined : Symbol(undefined)
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 289, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (o?.bar() !== undefined) {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 289, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>undefined : Symbol(undefined)
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 289, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+}
+
+function f20(o: Thing | undefined) {
+>f20 : Symbol(f20, Decl(controlFlowOptionalChain.ts, 299, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+
+    if (typeof o?.foo === "number") {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (typeof o?.["foo"] === "number") {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (typeof o?.bar() === "number") {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.baz instanceof Error) {
+>o?.baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+        o.baz;
+>o.baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 301, 13))
+>baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+    }
+}
+
+function f21(o: Thing | null) {
+>f21 : Symbol(f21, Decl(controlFlowOptionalChain.ts, 314, 1))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>Thing : Symbol(Thing, Decl(controlFlowOptionalChain.ts, 159, 1))
+
+    if (typeof o?.foo === "number") {
+>o?.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+
+        o.foo;
+>o.foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>foo : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (typeof o?.["foo"] === "number") {
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+
+        o["foo"];
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>"foo" : Symbol(foo, Decl(controlFlowOptionalChain.ts, 161, 14))
+    }
+    if (typeof o?.bar() === "number") {
+>o?.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+
+        o.bar;
+>o.bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>bar : Symbol(bar, Decl(controlFlowOptionalChain.ts, 161, 36))
+    }
+    if (o?.baz instanceof Error) {
+>o?.baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+>Error : Symbol(Error, Decl(lib.es5.d.ts, --, --), Decl(lib.es5.d.ts, --, --))
+
+        o.baz;
+>o.baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+>o : Symbol(o, Decl(controlFlowOptionalChain.ts, 316, 13))
+>baz : Symbol(baz, Decl(controlFlowOptionalChain.ts, 161, 51))
+    }
+}
+
diff --git a/tests/baselines/reference/controlFlowOptionalChain.types b/tests/baselines/reference/controlFlowOptionalChain.types
index a93c5b0b43f04..ffec7d1525e4e 100644
--- a/tests/baselines/reference/controlFlowOptionalChain.types
+++ b/tests/baselines/reference/controlFlowOptionalChain.types
@@ -208,18 +208,18 @@ if (o3?.x === 1) {
 >x : 1 | 2 | undefined
 >1 : 1
 
-    o3; // TODO: should be `{ x: y, y: string }`
->o3 : { x: 1; y: string; } | { x: 2; y: number; } | undefined
+    o3;
+>o3 : { x: 1; y: string; }
 
-    o3.x; // TODO: should not be an error.
+    o3.x;
 >o3.x : 1
->o3 : { x: 1; y: string; } | { x: 2; y: number; } | undefined
+>o3 : { x: 1; y: string; }
 >x : 1
 
     o3?.x;
->o3?.x : 1 | undefined
->o3 : { x: 1; y: string; } | { x: 2; y: number; } | undefined
->x : 1 | undefined
+>o3?.x : 1
+>o3 : { x: 1; y: string; }
+>x : 1
 }
 else {
     o3;
@@ -634,3 +634,656 @@ function f01(x: unknown) {
     }
 }
 
+type Thing = { foo: string | number, bar(): number, baz: object };
+>Thing : Thing
+>foo : string | number
+>bar : () => number
+>baz : object
+
+function f10(o: Thing | undefined, value: number) {
+>f10 : (o: Thing | undefined, value: number) => void
+>o : Thing | undefined
+>value : number
+
+    if (o?.foo === value) {
+>o?.foo === value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>value : number
+
+        o.foo;
+>o.foo : number
+>o : Thing
+>foo : number
+    }
+    if (o?.["foo"] === value) {
+>o?.["foo"] === value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>value : number
+
+        o["foo"];
+>o["foo"] : number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() === value) {
+>o?.bar() === value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>value : number
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+    if (o?.foo == value) {
+>o?.foo == value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>value : number
+
+        o.foo;
+>o.foo : string | number
+>o : Thing
+>foo : string | number
+    }
+    if (o?.["foo"] == value) {
+>o?.["foo"] == value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>value : number
+
+        o["foo"];
+>o["foo"] : string | number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() == value) {
+>o?.bar() == value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>value : number
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+}
+
+function f11(o: Thing | null, value: number) {
+>f11 : (o: Thing | null, value: number) => void
+>o : Thing | null
+>null : null
+>value : number
+
+    if (o?.foo === value) {
+>o?.foo === value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | null
+>foo : string | number | undefined
+>value : number
+
+        o.foo;
+>o.foo : number
+>o : Thing
+>foo : number
+    }
+    if (o?.["foo"] === value) {
+>o?.["foo"] === value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | null
+>"foo" : "foo"
+>value : number
+
+        o["foo"];
+>o["foo"] : number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() === value) {
+>o?.bar() === value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | null
+>bar : (() => number) | undefined
+>value : number
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+    if (o?.foo == value) {
+>o?.foo == value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | null
+>foo : string | number | undefined
+>value : number
+
+        o.foo;
+>o.foo : string | number
+>o : Thing
+>foo : string | number
+    }
+    if (o?.["foo"] == value) {
+>o?.["foo"] == value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | null
+>"foo" : "foo"
+>value : number
+
+        o["foo"];
+>o["foo"] : string | number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() == value) {
+>o?.bar() == value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | null
+>bar : (() => number) | undefined
+>value : number
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+}
+
+function f12(o: Thing | undefined, value: number | undefined) {
+>f12 : (o: Thing | undefined, value: number | undefined) => void
+>o : Thing | undefined
+>value : number | undefined
+
+    if (o?.foo === value) {
+>o?.foo === value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>value : number | undefined
+
+        o.foo;  // Error
+>o.foo : number
+>o : Thing | undefined
+>foo : number
+    }
+    if (o?.["foo"] === value) {
+>o?.["foo"] === value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>value : number | undefined
+
+        o["foo"];  // Error
+>o["foo"] : number
+>o : Thing | undefined
+>"foo" : "foo"
+    }
+    if (o?.bar() === value) {
+>o?.bar() === value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>value : number | undefined
+
+        o.bar;  // Error
+>o.bar : () => number
+>o : Thing | undefined
+>bar : () => number
+    }
+    if (o?.foo == value) {
+>o?.foo == value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>value : number | undefined
+
+        o.foo;  // Error
+>o.foo : number
+>o : Thing | undefined
+>foo : number
+    }
+    if (o?.["foo"] == value) {
+>o?.["foo"] == value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>value : number | undefined
+
+        o["foo"];  // Error
+>o["foo"] : number
+>o : Thing | undefined
+>"foo" : "foo"
+    }
+    if (o?.bar() == value) {
+>o?.bar() == value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>value : number | undefined
+
+        o.bar;  // Error
+>o.bar : () => number
+>o : Thing | undefined
+>bar : () => number
+    }
+}
+
+function f12a(o: Thing | undefined, value: number | null) {
+>f12a : (o: Thing | undefined, value: number | null) => void
+>o : Thing | undefined
+>value : number | null
+>null : null
+
+    if (o?.foo === value) {
+>o?.foo === value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>value : number | null
+
+        o.foo;
+>o.foo : number
+>o : Thing
+>foo : number
+    }
+    if (o?.["foo"] === value) {
+>o?.["foo"] === value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>value : number | null
+
+        o["foo"];
+>o["foo"] : number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() === value) {
+>o?.bar() === value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>value : number | null
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+    if (o?.foo == value) {
+>o?.foo == value : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>value : number | null
+
+        o.foo;  // Error
+>o.foo : number
+>o : Thing | undefined
+>foo : number
+    }
+    if (o?.["foo"] == value) {
+>o?.["foo"] == value : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>value : number | null
+
+        o["foo"];  // Error
+>o["foo"] : number
+>o : Thing | undefined
+>"foo" : "foo"
+    }
+    if (o?.bar() == value) {
+>o?.bar() == value : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>value : number | null
+
+        o.bar;  // Error
+>o.bar : () => number
+>o : Thing | undefined
+>bar : () => number
+    }
+}
+
+function f13(o: Thing | undefined) {
+>f13 : (o: Thing | undefined) => void
+>o : Thing | undefined
+
+    if (o?.foo !== undefined) {
+>o?.foo !== undefined : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>undefined : undefined
+
+        o.foo;
+>o.foo : string | number
+>o : Thing
+>foo : string | number
+    }
+    if (o?.["foo"] !== undefined) {
+>o?.["foo"] !== undefined : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>undefined : undefined
+
+        o["foo"];
+>o["foo"] : string | number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() !== undefined) {
+>o?.bar() !== undefined : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>undefined : undefined
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+    if (o?.foo != undefined) {
+>o?.foo != undefined : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>undefined : undefined
+
+        o.foo;
+>o.foo : string | number
+>o : Thing
+>foo : string | number
+    }
+    if (o?.["foo"] != undefined) {
+>o?.["foo"] != undefined : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>undefined : undefined
+
+        o["foo"];
+>o["foo"] : string | number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() != undefined) {
+>o?.bar() != undefined : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>undefined : undefined
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+}
+
+function f13a(o: Thing | undefined) {
+>f13a : (o: Thing | undefined) => void
+>o : Thing | undefined
+
+    if (o?.foo !== null) {
+>o?.foo !== null : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>null : null
+
+        o.foo;  // Error
+>o.foo : string | number
+>o : Thing | undefined
+>foo : string | number
+    }
+    if (o?.["foo"] !== null) {
+>o?.["foo"] !== null : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>null : null
+
+        o["foo"];  // Error
+>o["foo"] : string | number
+>o : Thing | undefined
+>"foo" : "foo"
+    }
+    if (o?.bar() !== null) {
+>o?.bar() !== null : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>null : null
+
+        o.bar;  // Error
+>o.bar : () => number
+>o : Thing | undefined
+>bar : () => number
+    }
+    if (o?.foo != null) {
+>o?.foo != null : boolean
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>null : null
+
+        o.foo;
+>o.foo : string | number
+>o : Thing
+>foo : string | number
+    }
+    if (o?.["foo"] != null) {
+>o?.["foo"] != null : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>null : null
+
+        o["foo"];
+>o["foo"] : string | number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() != null) {
+>o?.bar() != null : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>null : null
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+}
+
+function f14(o: Thing | null) {
+>f14 : (o: Thing | null) => void
+>o : Thing | null
+>null : null
+
+    if (o?.foo !== undefined) {
+>o?.foo !== undefined : boolean
+>o?.foo : string | number | undefined
+>o : Thing | null
+>foo : string | number | undefined
+>undefined : undefined
+
+        o.foo;
+>o.foo : string | number
+>o : Thing
+>foo : string | number
+    }
+    if (o?.["foo"] !== undefined) {
+>o?.["foo"] !== undefined : boolean
+>o?.["foo"] : string | number | undefined
+>o : Thing | null
+>"foo" : "foo"
+>undefined : undefined
+
+        o["foo"];
+>o["foo"] : string | number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (o?.bar() !== undefined) {
+>o?.bar() !== undefined : boolean
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | null
+>bar : (() => number) | undefined
+>undefined : undefined
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+}
+
+function f20(o: Thing | undefined) {
+>f20 : (o: Thing | undefined) => void
+>o : Thing | undefined
+
+    if (typeof o?.foo === "number") {
+>typeof o?.foo === "number" : boolean
+>typeof o?.foo : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>o?.foo : string | number | undefined
+>o : Thing | undefined
+>foo : string | number | undefined
+>"number" : "number"
+
+        o.foo;
+>o.foo : number
+>o : Thing
+>foo : number
+    }
+    if (typeof o?.["foo"] === "number") {
+>typeof o?.["foo"] === "number" : boolean
+>typeof o?.["foo"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>o?.["foo"] : string | number | undefined
+>o : Thing | undefined
+>"foo" : "foo"
+>"number" : "number"
+
+        o["foo"];
+>o["foo"] : number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (typeof o?.bar() === "number") {
+>typeof o?.bar() === "number" : boolean
+>typeof o?.bar() : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | undefined
+>bar : (() => number) | undefined
+>"number" : "number"
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+    if (o?.baz instanceof Error) {
+>o?.baz instanceof Error : boolean
+>o?.baz : object | undefined
+>o : Thing | undefined
+>baz : object | undefined
+>Error : ErrorConstructor
+
+        o.baz;
+>o.baz : Error
+>o : Thing
+>baz : Error
+    }
+}
+
+function f21(o: Thing | null) {
+>f21 : (o: Thing | null) => void
+>o : Thing | null
+>null : null
+
+    if (typeof o?.foo === "number") {
+>typeof o?.foo === "number" : boolean
+>typeof o?.foo : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>o?.foo : string | number | undefined
+>o : Thing | null
+>foo : string | number | undefined
+>"number" : "number"
+
+        o.foo;
+>o.foo : number
+>o : Thing
+>foo : number
+    }
+    if (typeof o?.["foo"] === "number") {
+>typeof o?.["foo"] === "number" : boolean
+>typeof o?.["foo"] : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>o?.["foo"] : string | number | undefined
+>o : Thing | null
+>"foo" : "foo"
+>"number" : "number"
+
+        o["foo"];
+>o["foo"] : number
+>o : Thing
+>"foo" : "foo"
+    }
+    if (typeof o?.bar() === "number") {
+>typeof o?.bar() === "number" : boolean
+>typeof o?.bar() : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
+>o?.bar() : number | undefined
+>o?.bar : (() => number) | undefined
+>o : Thing | null
+>bar : (() => number) | undefined
+>"number" : "number"
+
+        o.bar;
+>o.bar : () => number
+>o : Thing
+>bar : () => number
+    }
+    if (o?.baz instanceof Error) {
+>o?.baz instanceof Error : boolean
+>o?.baz : object | undefined
+>o : Thing | null
+>baz : object | undefined
+>Error : ErrorConstructor
+
+        o.baz;
+>o.baz : Error
+>o : Thing
+>baz : Error
+    }
+}
+
diff --git a/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts b/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts
index dadb1b36076db..f54275f309c34 100644
--- a/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts
+++ b/tests/cases/conformance/controlFlow/controlFlowOptionalChain.ts
@@ -61,8 +61,8 @@ o2.f;
 
 declare const o3: { x: 1, y: string } | { x: 2, y: number } | undefined;
 if (o3?.x === 1) {
-    o3; // TODO: should be `{ x: y, y: string }`
-    o3.x; // TODO: should not be an error.
+    o3;
+    o3.x;
     o3?.x;
 }
 else {
@@ -161,3 +161,173 @@ function f01(x: unknown) {
         x;
     }
 }
+
+type Thing = { foo: string | number, bar(): number, baz: object };
+
+function f10(o: Thing | undefined, value: number) {
+    if (o?.foo === value) {
+        o.foo;
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];
+    }
+    if (o?.bar() === value) {
+        o.bar;
+    }
+    if (o?.foo == value) {
+        o.foo;
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];
+    }
+    if (o?.bar() == value) {
+        o.bar;
+    }
+}
+
+function f11(o: Thing | null, value: number) {
+    if (o?.foo === value) {
+        o.foo;
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];
+    }
+    if (o?.bar() === value) {
+        o.bar;
+    }
+    if (o?.foo == value) {
+        o.foo;
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];
+    }
+    if (o?.bar() == value) {
+        o.bar;
+    }
+}
+
+function f12(o: Thing | undefined, value: number | undefined) {
+    if (o?.foo === value) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() === value) {
+        o.bar;  // Error
+    }
+    if (o?.foo == value) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() == value) {
+        o.bar;  // Error
+    }
+}
+
+function f12a(o: Thing | undefined, value: number | null) {
+    if (o?.foo === value) {
+        o.foo;
+    }
+    if (o?.["foo"] === value) {
+        o["foo"];
+    }
+    if (o?.bar() === value) {
+        o.bar;
+    }
+    if (o?.foo == value) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] == value) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() == value) {
+        o.bar;  // Error
+    }
+}
+
+function f13(o: Thing | undefined) {
+    if (o?.foo !== undefined) {
+        o.foo;
+    }
+    if (o?.["foo"] !== undefined) {
+        o["foo"];
+    }
+    if (o?.bar() !== undefined) {
+        o.bar;
+    }
+    if (o?.foo != undefined) {
+        o.foo;
+    }
+    if (o?.["foo"] != undefined) {
+        o["foo"];
+    }
+    if (o?.bar() != undefined) {
+        o.bar;
+    }
+}
+
+function f13a(o: Thing | undefined) {
+    if (o?.foo !== null) {
+        o.foo;  // Error
+    }
+    if (o?.["foo"] !== null) {
+        o["foo"];  // Error
+    }
+    if (o?.bar() !== null) {
+        o.bar;  // Error
+    }
+    if (o?.foo != null) {
+        o.foo;
+    }
+    if (o?.["foo"] != null) {
+        o["foo"];
+    }
+    if (o?.bar() != null) {
+        o.bar;
+    }
+}
+
+function f14(o: Thing | null) {
+    if (o?.foo !== undefined) {
+        o.foo;
+    }
+    if (o?.["foo"] !== undefined) {
+        o["foo"];
+    }
+    if (o?.bar() !== undefined) {
+        o.bar;
+    }
+}
+
+function f20(o: Thing | undefined) {
+    if (typeof o?.foo === "number") {
+        o.foo;
+    }
+    if (typeof o?.["foo"] === "number") {
+        o["foo"];
+    }
+    if (typeof o?.bar() === "number") {
+        o.bar;
+    }
+    if (o?.baz instanceof Error) {
+        o.baz;
+    }
+}
+
+function f21(o: Thing | null) {
+    if (typeof o?.foo === "number") {
+        o.foo;
+    }
+    if (typeof o?.["foo"] === "number") {
+        o["foo"];
+    }
+    if (typeof o?.bar() === "number") {
+        o.bar;
+    }
+    if (o?.baz instanceof Error) {
+        o.baz;
+    }
+}