Merge pull request #12064 from Microsoft/cacheSignatureInstantiations

Cache generic signature instantiations

Author: ahejlsberg

src/compiler/checker.ts

@@ -4232,7 +4232,7 @@ namespace ts {
             for (const baseSig of baseSignatures) {
                 const typeParamCount = baseSig.typeParameters ? baseSig.typeParameters.length : 0;
                 if (typeParamCount === typeArgCount) {
-                    const sig = typeParamCount ? getSignatureInstantiation(baseSig, typeArguments) : cloneSignature(baseSig);
+                    const sig = typeParamCount ? createSignatureInstantiation(baseSig, typeArguments) : cloneSignature(baseSig);
                     sig.typeParameters = classType.localTypeParameters;
                     sig.resolvedReturnType = classType;
                     result.push(sig);
@@ -4982,6 +4982,12 @@ namespace ts {
         }
 
         function getSignatureInstantiation(signature: Signature, typeArguments: Type[]): Signature {
+            const instantiations = signature.instantiations || (signature.instantiations = createMap<Signature>());
+            const id = getTypeListId(typeArguments);
+            return instantiations[id] || (instantiations[id] = createSignatureInstantiation(signature, typeArguments));
+        }
+
+        function createSignatureInstantiation(signature: Signature, typeArguments: Type[]): Signature {
             return instantiateSignature(signature, createTypeMapper(signature.typeParameters, typeArguments), /*eraseTypeParameters*/ true);
         }
 

src/compiler/types.ts

@@ -2923,6 +2923,8 @@ namespace ts {
         isolatedSignatureType?: ObjectType; // A manufactured type that just contains the signature for purposes of signature comparison
         /* @internal */
         typePredicate?: TypePredicate;
+        /* @internal */
+        instantiations?: Map<Signature>;    // Generic signature instantiation cache
     }
 
     export const enum IndexKind {

tests/baselines/reference/promisePermutations.errors.txt

@@ -25,8 +25,6 @@ tests/cases/compiler/promisePermutations.ts(106,19): error TS2345: Argument of t
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations.ts(109,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-  Types of parameters 'cb' and 'value' are incompatible.
-    Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations.ts(110,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
@@ -229,8 +227,6 @@ tests/cases/compiler/promisePermutations.ts(160,21): error TS2345: Argument of t
     var s7a = r7.then(testFunction7, testFunction7, testFunction7); // error
                       ~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-!!! error TS2345:   Types of parameters 'cb' and 'value' are incompatible.
-!!! error TS2345:     Type 'string' is not assignable to type '<T>(a: T) => T'.
     var s7b = r7.then(testFunction7P, testFunction7P, testFunction7P); // error
                       ~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.

tests/baselines/reference/promisePermutations2.errors.txt

@@ -25,8 +25,6 @@ tests/cases/compiler/promisePermutations2.ts(105,19): error TS2345: Argument of
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations2.ts(108,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-  Types of parameters 'cb' and 'value' are incompatible.
-    Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations2.ts(109,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
@@ -228,8 +226,6 @@ tests/cases/compiler/promisePermutations2.ts(159,21): error TS2345: Argument of
     var s7a = r7.then(testFunction7, testFunction7, testFunction7); // error
                       ~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-!!! error TS2345:   Types of parameters 'cb' and 'value' are incompatible.
-!!! error TS2345:     Type 'string' is not assignable to type '<T>(a: T) => T'.
     var s7b = r7.then(testFunction7P, testFunction7P, testFunction7P); // error
                       ~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.

tests/baselines/reference/promisePermutations3.errors.txt

@@ -28,8 +28,6 @@ tests/cases/compiler/promisePermutations3.ts(105,19): error TS2345: Argument of
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations3.ts(108,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-  Types of parameters 'cb' and 'value' are incompatible.
-    Type 'string' is not assignable to type '<T>(a: T) => T'.
 tests/cases/compiler/promisePermutations3.ts(109,19): error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.
   Types of parameters 'cb' and 'value' are incompatible.
     Type 'string' is not assignable to type '<T>(a: T) => T'.
@@ -240,8 +238,6 @@ tests/cases/compiler/promisePermutations3.ts(165,21): error TS2345: Argument of
     var s7a = r7.then(testFunction7, testFunction7, testFunction7); // error
                       ~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => IPromise<string>' is not assignable to parameter of type '(value: string) => IPromise<string>'.
-!!! error TS2345:   Types of parameters 'cb' and 'value' are incompatible.
-!!! error TS2345:     Type 'string' is not assignable to type '<T>(a: T) => T'.
     var s7b = r7.then(testFunction7P, testFunction7P, testFunction7P); // error
                       ~~~~~~~~~~~~~~
 !!! error TS2345: Argument of type '(cb: <T>(a: T) => T) => Promise<string>' is not assignable to parameter of type '(value: string) => Promise<string>'.