From f104b53c050725f72a19f4d631817a5feb1e3529 Mon Sep 17 00:00:00 2001
From: Anders Hejlsberg <andersh@microsoft.com>
Date: Thu, 4 May 2023 16:56:20 -0700
Subject: [PATCH] Revert changes and instead fix isGenericObjectType to be more
 conservative

---
 src/compiler/checker.ts | 13 ++-----------
 src/compiler/types.ts   | 19 +++++++++----------
 2 files changed, 11 insertions(+), 21 deletions(-)

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 63f6fda4225f1..bf49a02fc963f 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -14078,7 +14078,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
             else if (type !== firstType) {
                 checkFlags |= CheckFlags.HasNonUniformType;
             }
-            if (isLiteralType(type) || isPatternLiteralType(type) || type === uniqueLiteralType) {
+            if (isLiteralType(type) || isPatternLiteralType(type)) {
                 checkFlags |= CheckFlags.HasLiteralType;
             }
             if (type.flags & TypeFlags.Never && type !== uniqueLiteralType) {
@@ -17685,7 +17685,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         // eagerly using the constraint type of 'this' at the given location.
         if (isGenericIndexType(indexType) || (accessNode && accessNode.kind !== SyntaxKind.IndexedAccessType ?
             isGenericTupleType(objectType) && !indexTypeLessThan(indexType, objectType.target.fixedLength) :
-            isGenericObjectType(objectType) && !(isTupleType(objectType) && indexTypeLessThan(indexType, objectType.target.fixedLength)) || !(accessFlags & AccessFlags.ResolveReducibleTypes) && isGenericReducibleType(objectType))) {
+            isGenericObjectType(objectType) && !(isTupleType(objectType) && indexTypeLessThan(indexType, objectType.target.fixedLength)) || isGenericReducibleType(objectType))) {
             if (objectType.flags & TypeFlags.AnyOrUnknown) {
                 return objectType;
             }
@@ -24511,15 +24511,6 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
                         }
                     }
                 }
-                // The following is a targeted fix to allow higher-kinded types to be emulated using the technique in #53970.
-                // Specifically, when an indexed access type was deferred because it has a reducible object type, here we force
-                // resolution of the type and then infer to the result.
-                if (target.flags & TypeFlags.IndexedAccess && isGenericReducibleType((target as IndexedAccessType).objectType)) {
-                    const instantiated = getIndexedAccessType((target as IndexedAccessType).objectType, (target as IndexedAccessType).indexType, AccessFlags.ResolveReducibleTypes);
-                    if (instantiated && instantiated !== target) {
-                        inferFromTypes(source, instantiated);
-                    }
-                }
             }
             if (getObjectFlags(source) & ObjectFlags.Reference && getObjectFlags(target) & ObjectFlags.Reference && (
                 (source as TypeReference).target === (target as TypeReference).target || isArrayType(source) && isArrayType(target)) &&
diff --git a/src/compiler/types.ts b/src/compiler/types.ts
index 122ed908792fa..c97bbaffa2834 100644
--- a/src/compiler/types.ts
+++ b/src/compiler/types.ts
@@ -6593,16 +6593,15 @@ export interface TypeParameter extends InstantiableType {
 export const enum AccessFlags {
     None = 0,
     IncludeUndefined = 1 << 0,
-    ResolveReducibleTypes = 1 << 1,
-    NoIndexSignatures = 1 << 2,
-    Writing = 1 << 3,
-    CacheSymbol = 1 << 4,
-    NoTupleBoundsCheck = 1 << 5,
-    ExpressionPosition = 1 << 6,
-    ReportDeprecated = 1 << 7,
-    SuppressNoImplicitAnyError = 1 << 8,
-    Contextual = 1 << 9,
-    Persistent = IncludeUndefined | ResolveReducibleTypes,
+    NoIndexSignatures = 1 << 1,
+    Writing = 1 << 2,
+    CacheSymbol = 1 << 3,
+    NoTupleBoundsCheck = 1 << 4,
+    ExpressionPosition = 1 << 5,
+    ReportDeprecated = 1 << 6,
+    SuppressNoImplicitAnyError = 1 << 7,
+    Contextual = 1 << 8,
+    Persistent = IncludeUndefined,
 }
 
 // Indexed access types (TypeFlags.IndexedAccess)