Allow non-generic return types to be read from single generic call signatures

src/compiler/checker.ts

@@ -38856,17 +38856,20 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         }
     }
 
-    function getReturnTypeOfSingleNonGenericCallSignature(funcType: Type) {
+    function getNonGenericReturnTypeOfSingleCallSignature(funcType: Type) {
         const signature = getSingleCallSignature(funcType);
-        if (signature && !signature.typeParameters) {
-            return getReturnTypeOfSignature(signature);
+        if (signature) {
+            const returnType = getReturnTypeOfSignature(signature);
+            if (!signature.typeParameters || !couldContainTypeVariables(returnType)) {
+                return returnType;
+            }
         }
     }
 
     function getReturnTypeOfSingleNonGenericSignatureOfCallChain(expr: CallChain) {
         const funcType = checkExpression(expr.expression);
         const nonOptionalType = getOptionalExpressionType(funcType, expr.expression);
-        const returnType = getReturnTypeOfSingleNonGenericCallSignature(funcType);
+        const returnType = getNonGenericReturnTypeOfSingleCallSignature(funcType);
         return returnType && propagateOptionalTypeMarker(returnType, expr, nonOptionalType !== funcType);
     }
 
@@ -38915,7 +38918,7 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
         // signature where we can just fetch the return type without checking the arguments.
         if (isCallExpression(expr) && expr.expression.kind !== SyntaxKind.SuperKeyword && !isRequireCall(expr, /*requireStringLiteralLikeArgument*/ true) && !isSymbolOrSymbolForCall(expr)) {
             return isCallChain(expr) ? getReturnTypeOfSingleNonGenericSignatureOfCallChain(expr) :
-                getReturnTypeOfSingleNonGenericCallSignature(checkNonNullExpression(expr.expression));
+                getNonGenericReturnTypeOfSingleCallSignature(checkNonNullExpression(expr.expression));
         }
         else if (isAssertionExpression(expr) && !isConstTypeReference(expr.type)) {
             return getTypeFromTypeNode((expr as TypeAssertion).type);

tests/baselines/reference/arrayFrom.types

@@ -31,7 +31,7 @@ const inputALike: ArrayLike<A> = { length: 0 };
 const inputARand = getEither(inputA, inputALike);
 >inputARand : ArrayLike<A> | Iterable<A>
 >getEither(inputA, inputALike) : ArrayLike<A> | Iterable<A>
->getEither : <T>(in1: Iterable<T>, in2: ArrayLike<T>) => ArrayLike<T> | Iterable<T>
+>getEither : <T>(in1: Iterable<T>, in2: ArrayLike<T>) => Iterable<T> | ArrayLike<T>
 >inputA : A[]
 >inputALike : ArrayLike<A>
 
@@ -163,12 +163,12 @@ const result11: B[] = Array.from(inputASet, ({ a }): B => ({ b: a }));
 // the ?: as always taking the false branch, narrowing to ArrayLike<T>,
 // even when the type is written as : Iterable<T>|ArrayLike<T>
 function getEither<T> (in1: Iterable<T>, in2: ArrayLike<T>) {
->getEither : <T>(in1: Iterable<T>, in2: ArrayLike<T>) => ArrayLike<T> | Iterable<T>
+>getEither : <T>(in1: Iterable<T>, in2: ArrayLike<T>) => Iterable<T> | ArrayLike<T>
 >in1 : Iterable<T>
 >in2 : ArrayLike<T>
 
   return Math.random() > 0.5 ? in1 : in2;
->Math.random() > 0.5 ? in1 : in2 : ArrayLike<T> | Iterable<T>
+>Math.random() > 0.5 ? in1 : in2 : Iterable<T> | ArrayLike<T>
 >Math.random() > 0.5 : boolean
 >Math.random() : number
 >Math.random : () => number

tests/baselines/reference/circularReferenceInReturnType.symbols

@@ -0,0 +1,41 @@
+//// [tests/cases/compiler/circularReferenceInReturnType.ts] ////
+
+=== circularReferenceInReturnType.ts ===
+declare function fn1<T>(cb: () => T): string;
+>fn1 : Symbol(fn1, Decl(circularReferenceInReturnType.ts, 0, 0))
+>T : Symbol(T, Decl(circularReferenceInReturnType.ts, 0, 21))
+>cb : Symbol(cb, Decl(circularReferenceInReturnType.ts, 0, 24))
+>T : Symbol(T, Decl(circularReferenceInReturnType.ts, 0, 21))
+
+const res1 = fn1(() => res1);
+>res1 : Symbol(res1, Decl(circularReferenceInReturnType.ts, 1, 5))
+>fn1 : Symbol(fn1, Decl(circularReferenceInReturnType.ts, 0, 0))
+>res1 : Symbol(res1, Decl(circularReferenceInReturnType.ts, 1, 5))
+
+declare function fn2<T>(): (cb: () => any) => (a: T) => void;
+>fn2 : Symbol(fn2, Decl(circularReferenceInReturnType.ts, 1, 29))
+>T : Symbol(T, Decl(circularReferenceInReturnType.ts, 3, 21))
+>cb : Symbol(cb, Decl(circularReferenceInReturnType.ts, 3, 28))
+>a : Symbol(a, Decl(circularReferenceInReturnType.ts, 3, 47))
+>T : Symbol(T, Decl(circularReferenceInReturnType.ts, 3, 21))
+
+const res2 = fn2()(() => res2);
+>res2 : Symbol(res2, Decl(circularReferenceInReturnType.ts, 4, 5))
+>fn2 : Symbol(fn2, Decl(circularReferenceInReturnType.ts, 1, 29))
+>res2 : Symbol(res2, Decl(circularReferenceInReturnType.ts, 4, 5))
+
+declare function fn3<T>(): <T2>(cb: (arg: T2) => any) => (a: T) => void;
+>fn3 : Symbol(fn3, Decl(circularReferenceInReturnType.ts, 4, 31))
+>T : Symbol(T, Decl(circularReferenceInReturnType.ts, 6, 21))
+>T2 : Symbol(T2, Decl(circularReferenceInReturnType.ts, 6, 28))
+>cb : Symbol(cb, Decl(circularReferenceInReturnType.ts, 6, 32))
+>arg : Symbol(arg, Decl(circularReferenceInReturnType.ts, 6, 37))
+>T2 : Symbol(T2, Decl(circularReferenceInReturnType.ts, 6, 28))
+>a : Symbol(a, Decl(circularReferenceInReturnType.ts, 6, 58))
+>T : Symbol(T, Decl(circularReferenceInReturnType.ts, 6, 21))
+
+const res3 = fn3()(() => res3);
+>res3 : Symbol(res3, Decl(circularReferenceInReturnType.ts, 7, 5))
+>fn3 : Symbol(fn3, Decl(circularReferenceInReturnType.ts, 4, 31))
+>res3 : Symbol(res3, Decl(circularReferenceInReturnType.ts, 7, 5))
+

tests/baselines/reference/circularReferenceInReturnType.types

@@ -0,0 +1,41 @@
+//// [tests/cases/compiler/circularReferenceInReturnType.ts] ////
+
+=== circularReferenceInReturnType.ts ===
+declare function fn1<T>(cb: () => T): string;
+>fn1 : <T>(cb: () => T) => string
+>cb : () => T
+
+const res1 = fn1(() => res1);
+>res1 : string
+>fn1(() => res1) : string
+>fn1 : <T>(cb: () => T) => string
+>() => res1 : () => string
+>res1 : string
+
+declare function fn2<T>(): (cb: () => any) => (a: T) => void;
+>fn2 : <T>() => (cb: () => any) => (a: T) => void
+>cb : () => any
+>a : T
+
+const res2 = fn2()(() => res2);
+>res2 : (a: unknown) => void
+>fn2()(() => res2) : (a: unknown) => void
+>fn2() : (cb: () => any) => (a: unknown) => void
+>fn2 : <T>() => (cb: () => any) => (a: T) => void
+>() => res2 : () => (a: unknown) => void
+>res2 : (a: unknown) => void
+
+declare function fn3<T>(): <T2>(cb: (arg: T2) => any) => (a: T) => void;
+>fn3 : <T>() => <T2>(cb: (arg: T2) => any) => (a: T) => void
+>cb : (arg: T2) => any
+>arg : T2
+>a : T
+
+const res3 = fn3()(() => res3);
+>res3 : (a: unknown) => void
+>fn3()(() => res3) : (a: unknown) => void
+>fn3() : <T2>(cb: (arg: T2) => any) => (a: unknown) => void
+>fn3 : <T>() => <T2>(cb: (arg: T2) => any) => (a: T) => void
+>() => res3 : () => (a: unknown) => void
+>res3 : (a: unknown) => void
+

tests/baselines/reference/circularReferenceInReturnType2.symbols

@@ -0,0 +1,160 @@
+//// [tests/cases/compiler/circularReferenceInReturnType2.ts] ////
+
+=== circularReferenceInReturnType2.ts ===
+type ObjectType<Source> = {
+>ObjectType : Symbol(ObjectType, Decl(circularReferenceInReturnType2.ts, 0, 0))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 0, 16))
+
+  kind: "object";
+>kind : Symbol(kind, Decl(circularReferenceInReturnType2.ts, 0, 27))
+
+  __source: (source: Source) => void;
+>__source : Symbol(__source, Decl(circularReferenceInReturnType2.ts, 1, 17))
+>source : Symbol(source, Decl(circularReferenceInReturnType2.ts, 2, 13))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 0, 16))
+
+};
+
+type Field<Source, Key extends string> = {
+>Field : Symbol(Field, Decl(circularReferenceInReturnType2.ts, 3, 2))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 5, 11))
+>Key : Symbol(Key, Decl(circularReferenceInReturnType2.ts, 5, 18))
+
+  __key: (key: Key) => void;
+>__key : Symbol(__key, Decl(circularReferenceInReturnType2.ts, 5, 42))
+>key : Symbol(key, Decl(circularReferenceInReturnType2.ts, 6, 10))
+>Key : Symbol(Key, Decl(circularReferenceInReturnType2.ts, 5, 18))
+
+  __source: (source: Source) => void;
+>__source : Symbol(__source, Decl(circularReferenceInReturnType2.ts, 6, 28))
+>source : Symbol(source, Decl(circularReferenceInReturnType2.ts, 7, 13))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 5, 11))
+
+};
+
+declare const object: <Source>() => <
+>object : Symbol(object, Decl(circularReferenceInReturnType2.ts, 10, 13))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 10, 23))
+
+  Fields extends {
+>Fields : Symbol(Fields, Decl(circularReferenceInReturnType2.ts, 10, 37))
+
+    [Key in keyof Fields]: Field<Source, Key & string>;
+>Key : Symbol(Key, Decl(circularReferenceInReturnType2.ts, 12, 5))
+>Fields : Symbol(Fields, Decl(circularReferenceInReturnType2.ts, 10, 37))
+>Field : Symbol(Field, Decl(circularReferenceInReturnType2.ts, 3, 2))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 10, 23))
+>Key : Symbol(Key, Decl(circularReferenceInReturnType2.ts, 12, 5))
+  }
+>(config: {
+>config : Symbol(config, Decl(circularReferenceInReturnType2.ts, 14, 2))
+
+  name: string;
+>name : Symbol(name, Decl(circularReferenceInReturnType2.ts, 14, 11))
+
+  fields: Fields | (() => Fields);
+>fields : Symbol(fields, Decl(circularReferenceInReturnType2.ts, 15, 15))
+>Fields : Symbol(Fields, Decl(circularReferenceInReturnType2.ts, 10, 37))
+>Fields : Symbol(Fields, Decl(circularReferenceInReturnType2.ts, 10, 37))
+
+}) => ObjectType<Source>;
+>ObjectType : Symbol(ObjectType, Decl(circularReferenceInReturnType2.ts, 0, 0))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 10, 23))
+
+type InferValueFromObjectType<Type extends ObjectType<any>> =
+>InferValueFromObjectType : Symbol(InferValueFromObjectType, Decl(circularReferenceInReturnType2.ts, 17, 25))
+>Type : Symbol(Type, Decl(circularReferenceInReturnType2.ts, 19, 30))
+>ObjectType : Symbol(ObjectType, Decl(circularReferenceInReturnType2.ts, 0, 0))
+
+  Type extends ObjectType<infer Source> ? Source : never;
+>Type : Symbol(Type, Decl(circularReferenceInReturnType2.ts, 19, 30))
+>ObjectType : Symbol(ObjectType, Decl(circularReferenceInReturnType2.ts, 0, 0))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 20, 31))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 20, 31))
+
+type FieldResolver<Source, TType extends ObjectType<any>> = (
+>FieldResolver : Symbol(FieldResolver, Decl(circularReferenceInReturnType2.ts, 20, 57))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 22, 19))
+>TType : Symbol(TType, Decl(circularReferenceInReturnType2.ts, 22, 26))
+>ObjectType : Symbol(ObjectType, Decl(circularReferenceInReturnType2.ts, 0, 0))
+
+  source: Source
+>source : Symbol(source, Decl(circularReferenceInReturnType2.ts, 22, 61))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 22, 19))
+
+) => InferValueFromObjectType<TType>;
+>InferValueFromObjectType : Symbol(InferValueFromObjectType, Decl(circularReferenceInReturnType2.ts, 17, 25))
+>TType : Symbol(TType, Decl(circularReferenceInReturnType2.ts, 22, 26))
+
+type FieldFuncArgs<Source, Type extends ObjectType<any>> = {
+>FieldFuncArgs : Symbol(FieldFuncArgs, Decl(circularReferenceInReturnType2.ts, 24, 37))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 26, 19))
+>Type : Symbol(Type, Decl(circularReferenceInReturnType2.ts, 26, 26))
+>ObjectType : Symbol(ObjectType, Decl(circularReferenceInReturnType2.ts, 0, 0))
+
+  type: Type;
+>type : Symbol(type, Decl(circularReferenceInReturnType2.ts, 26, 60))
+>Type : Symbol(Type, Decl(circularReferenceInReturnType2.ts, 26, 26))
+
+  resolve: FieldResolver<Source, Type>;
+>resolve : Symbol(resolve, Decl(circularReferenceInReturnType2.ts, 27, 13))
+>FieldResolver : Symbol(FieldResolver, Decl(circularReferenceInReturnType2.ts, 20, 57))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 26, 19))
+>Type : Symbol(Type, Decl(circularReferenceInReturnType2.ts, 26, 26))
+
+};
+
+declare const field: <Source, Type extends ObjectType<any>, Key extends string>(
+>field : Symbol(field, Decl(circularReferenceInReturnType2.ts, 31, 13))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 31, 22))
+>Type : Symbol(Type, Decl(circularReferenceInReturnType2.ts, 31, 29))
+>ObjectType : Symbol(ObjectType, Decl(circularReferenceInReturnType2.ts, 0, 0))
+>Key : Symbol(Key, Decl(circularReferenceInReturnType2.ts, 31, 59))
+
+  field: FieldFuncArgs<Source, Type>
+>field : Symbol(field, Decl(circularReferenceInReturnType2.ts, 31, 80))
+>FieldFuncArgs : Symbol(FieldFuncArgs, Decl(circularReferenceInReturnType2.ts, 24, 37))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 31, 22))
+>Type : Symbol(Type, Decl(circularReferenceInReturnType2.ts, 31, 29))
+
+) => Field<Source, Key>;
+>Field : Symbol(Field, Decl(circularReferenceInReturnType2.ts, 3, 2))
+>Source : Symbol(Source, Decl(circularReferenceInReturnType2.ts, 31, 22))
+>Key : Symbol(Key, Decl(circularReferenceInReturnType2.ts, 31, 59))
+
+type Something = { foo: number };
+>Something : Symbol(Something, Decl(circularReferenceInReturnType2.ts, 33, 24))
+>foo : Symbol(foo, Decl(circularReferenceInReturnType2.ts, 35, 18))
+
+const A = object<Something>()({
+>A : Symbol(A, Decl(circularReferenceInReturnType2.ts, 37, 5))
+>object : Symbol(object, Decl(circularReferenceInReturnType2.ts, 10, 13))
+>Something : Symbol(Something, Decl(circularReferenceInReturnType2.ts, 33, 24))
+
+  name: "A",
+>name : Symbol(name, Decl(circularReferenceInReturnType2.ts, 37, 31))
+
+  fields: () => ({
+>fields : Symbol(fields, Decl(circularReferenceInReturnType2.ts, 38, 12))
+
+    a: field({
+>a : Symbol(a, Decl(circularReferenceInReturnType2.ts, 39, 18))
+>field : Symbol(field, Decl(circularReferenceInReturnType2.ts, 31, 13))
+
+      type: A,
+>type : Symbol(type, Decl(circularReferenceInReturnType2.ts, 40, 14))
+>A : Symbol(A, Decl(circularReferenceInReturnType2.ts, 37, 5))
+
+      resolve() {
+>resolve : Symbol(resolve, Decl(circularReferenceInReturnType2.ts, 41, 14))
+
+        return {
+          foo: 100,
+>foo : Symbol(foo, Decl(circularReferenceInReturnType2.ts, 43, 16))
+
+        };
+      },
+    }),
+  }),
+});
+