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Fix type variable leaks and cache inconsistencies #61668

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Fix type variable leaks and cache inconsistencies #61668

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994f390
Revert "Propagate outer type parameters of single signature types (#5…
ahejlsberg May 3, 2025
16bc58f
Propagate base type mapper in signatures with inferred type parameters
ahejlsberg May 5, 2025
7d0dea0
Introduce and use createOuterReturnTypeMapper function
ahejlsberg May 7, 2025
93ef50e
Accept new baselines
ahejlsberg May 7, 2025
065c199
Add/modify tests
ahejlsberg May 7, 2025
d066cb2
Accept new baselines
ahejlsberg May 7, 2025
0ca87b3
Formatting
ahejlsberg May 7, 2025
defd353
Include inferences from preceding outer arguments
ahejlsberg May 8, 2025
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114 changes: 37 additions & 77 deletions src/compiler/checker.ts
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11 changes: 1 addition & 10 deletions src/compiler/types.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -6492,7 +6492,7 @@ export const enum ObjectFlags {
CouldContainTypeVariablesComputed = 1 << 19, // CouldContainTypeVariables flag has been computed
/** @internal */
CouldContainTypeVariables = 1 << 20, // Type could contain a type variable

SingleSignatureType = 1 << 27, // A single signature type extracted from a potentially broader type
ClassOrInterface = Class | Interface,
/** @internal */
RequiresWidening = ContainsWideningType | ContainsObjectOrArrayLiteral,
Expand All @@ -6508,7 +6508,6 @@ export const enum ObjectFlags {
ContainsSpread = 1 << 21, // Object literal contains spread operation
ObjectRestType = 1 << 22, // Originates in object rest declaration
InstantiationExpressionType = 1 << 23, // Originates in instantiation expression
SingleSignatureType = 1 << 27, // A single signature type extracted from a potentially broader type
/** @internal */
IsClassInstanceClone = 1 << 24, // Type is a clone of a class instance type
// Flags that require TypeFlags.Object and ObjectFlags.Reference
Expand Down Expand Up @@ -6723,12 +6722,6 @@ export interface AnonymousType extends ObjectType {
instantiations?: Map<string, Type>; // Instantiations of generic type alias (undefined if non-generic)
}

/** @internal */
// A SingleSignatureType may have bespoke outer type parameters to handle free type variable inferences
export interface SingleSignatureType extends AnonymousType {
outerTypeParameters?: TypeParameter[];
}

/** @internal */
export interface InstantiationExpressionType extends AnonymousType {
node: NodeWithTypeArguments;
Expand Down Expand Up @@ -7014,8 +7007,6 @@ export interface Signature {
isolatedSignatureType?: ObjectType; // A manufactured type that just contains the signature for purposes of signature comparison
/** @internal */
instantiations?: Map<string, Signature>; // Generic signature instantiation cache
/** @internal */
implementationSignatureCache?: Signature; // Copy of the signature with fresh type parameters to use in checking the body of a potentially self-referential generic function (deferred)
}

export const enum IndexKind {
Expand Down
2 changes: 1 addition & 1 deletion tests/baselines/reference/api/typescript.d.ts
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Expand Up @@ -6705,11 +6705,11 @@ declare namespace ts {
JSLiteral = 4096,
FreshLiteral = 8192,
ArrayLiteral = 16384,
SingleSignatureType = 134217728,
ClassOrInterface = 3,
ContainsSpread = 2097152,
ObjectRestType = 4194304,
InstantiationExpressionType = 8388608,
SingleSignatureType = 134217728,
}
interface ObjectType extends Type {
objectFlags: ObjectFlags;
Expand Down
2 changes: 1 addition & 1 deletion tests/baselines/reference/declarationEmitHigherOrderRetainedGenerics.types
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Expand Up @@ -2,7 +2,7 @@

=== Performance Stats ===
Type Count: 1,000
Instantiation count: 2,500 -> 5,000
Instantiation count: 2,500

=== declarationEmitHigherOrderRetainedGenerics.ts ===
export interface TypeLambda {
Expand Down
173 changes: 173 additions & 0 deletions tests/baselines/reference/genericCallInferenceInConditionalTypes1.symbols
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@@ -0,0 +1,173 @@
//// [tests/cases/compiler/genericCallInferenceInConditionalTypes1.ts] ////

=== genericCallInferenceInConditionalTypes1.ts ===
// https://github.com/microsoft/TypeScript/issues/59937

type Ref<T> = {
>Ref : Symbol(Ref, Decl(genericCallInferenceInConditionalTypes1.ts, 0, 0))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 2, 9))

current: T;
>current : Symbol(current, Decl(genericCallInferenceInConditionalTypes1.ts, 2, 15))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 2, 9))

};

type FunctionComponent<P> = (props: P) => unknown;
>FunctionComponent : Symbol(FunctionComponent, Decl(genericCallInferenceInConditionalTypes1.ts, 4, 2))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 23))
>props : Symbol(props, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 29))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 23))

type ComponentProps<T extends FunctionComponent<any>> =
>ComponentProps : Symbol(ComponentProps, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 50))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 8, 20))
>FunctionComponent : Symbol(FunctionComponent, Decl(genericCallInferenceInConditionalTypes1.ts, 4, 2))

T extends FunctionComponent<infer P> ? P : {};
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 8, 20))
>FunctionComponent : Symbol(FunctionComponent, Decl(genericCallInferenceInConditionalTypes1.ts, 4, 2))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 9, 35))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 9, 35))

type PropsWithoutRef<P> = P extends any
>PropsWithoutRef : Symbol(PropsWithoutRef, Decl(genericCallInferenceInConditionalTypes1.ts, 9, 48))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 11, 21))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 11, 21))

? "ref" extends keyof P
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 11, 21))

? Omit<P, "ref">
>Omit : Symbol(Omit, Decl(lib.es5.d.ts, --, --))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 11, 21))

: P
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 11, 21))

: P;
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 11, 21))

type ComponentPropsWithoutRef<T extends FunctionComponent<any>> =
>ComponentPropsWithoutRef : Symbol(ComponentPropsWithoutRef, Decl(genericCallInferenceInConditionalTypes1.ts, 15, 6))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 17, 30))
>FunctionComponent : Symbol(FunctionComponent, Decl(genericCallInferenceInConditionalTypes1.ts, 4, 2))

PropsWithoutRef<ComponentProps<T>>;
>PropsWithoutRef : Symbol(PropsWithoutRef, Decl(genericCallInferenceInConditionalTypes1.ts, 9, 48))
>ComponentProps : Symbol(ComponentProps, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 50))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 17, 30))

declare function forwardRef<T, P>(
>forwardRef : Symbol(forwardRef, Decl(genericCallInferenceInConditionalTypes1.ts, 18, 37))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 20, 28))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 20, 30))

component: (props: P, ref: Ref<T>) => unknown,
>component : Symbol(component, Decl(genericCallInferenceInConditionalTypes1.ts, 20, 34))
>props : Symbol(props, Decl(genericCallInferenceInConditionalTypes1.ts, 21, 14))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 20, 30))
>ref : Symbol(ref, Decl(genericCallInferenceInConditionalTypes1.ts, 21, 23))
>Ref : Symbol(Ref, Decl(genericCallInferenceInConditionalTypes1.ts, 0, 0))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 20, 28))

): (props: P & { ref?: Ref<T> }) => unknown;
>props : Symbol(props, Decl(genericCallInferenceInConditionalTypes1.ts, 22, 4))
>P : Symbol(P, Decl(genericCallInferenceInConditionalTypes1.ts, 20, 30))
>ref : Symbol(ref, Decl(genericCallInferenceInConditionalTypes1.ts, 22, 16))
>Ref : Symbol(Ref, Decl(genericCallInferenceInConditionalTypes1.ts, 0, 0))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 20, 28))

const ComponentWithForwardRef = forwardRef(
>ComponentWithForwardRef : Symbol(ComponentWithForwardRef, Decl(genericCallInferenceInConditionalTypes1.ts, 24, 5))
>forwardRef : Symbol(forwardRef, Decl(genericCallInferenceInConditionalTypes1.ts, 18, 37))

<T extends FunctionComponent<any>>(
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 25, 3))
>FunctionComponent : Symbol(FunctionComponent, Decl(genericCallInferenceInConditionalTypes1.ts, 4, 2))

props: ComponentPropsWithoutRef<T>,
>props : Symbol(props, Decl(genericCallInferenceInConditionalTypes1.ts, 25, 37))
>ComponentPropsWithoutRef : Symbol(ComponentPropsWithoutRef, Decl(genericCallInferenceInConditionalTypes1.ts, 15, 6))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 25, 3))

ref: Ref<HTMLElement>,
>ref : Symbol(ref, Decl(genericCallInferenceInConditionalTypes1.ts, 26, 39))
>Ref : Symbol(Ref, Decl(genericCallInferenceInConditionalTypes1.ts, 0, 0))
>HTMLElement : Symbol(HTMLElement, Decl(lib.dom.d.ts, --, --), Decl(lib.dom.d.ts, --, --))

) => {
return null;
},
);

type Test<T> = T extends { component?: infer Component }
>Test : Symbol(Test, Decl(genericCallInferenceInConditionalTypes1.ts, 31, 2))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 33, 10))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 33, 10))
>component : Symbol(component, Decl(genericCallInferenceInConditionalTypes1.ts, 33, 26))
>Component : Symbol(Component, Decl(genericCallInferenceInConditionalTypes1.ts, 33, 44))

? Component extends FunctionComponent<any>
>Component : Symbol(Component, Decl(genericCallInferenceInConditionalTypes1.ts, 33, 44))
>FunctionComponent : Symbol(FunctionComponent, Decl(genericCallInferenceInConditionalTypes1.ts, 4, 2))

? ComponentProps<Component>
>ComponentProps : Symbol(ComponentProps, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 50))
>Component : Symbol(Component, Decl(genericCallInferenceInConditionalTypes1.ts, 33, 44))

: never
: never;

// the first one here has a chance to pollute the cache
type Result1 = ComponentProps<typeof ComponentWithForwardRef>;
>Result1 : Symbol(Result1, Decl(genericCallInferenceInConditionalTypes1.ts, 37, 10))
>ComponentProps : Symbol(ComponentProps, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 50))
>ComponentWithForwardRef : Symbol(ComponentWithForwardRef, Decl(genericCallInferenceInConditionalTypes1.ts, 24, 5))

// that could be incorrectly reused by this one
type Result2 = Test<{ component: typeof ComponentWithForwardRef }>; // no `T` leak
>Result2 : Symbol(Result2, Decl(genericCallInferenceInConditionalTypes1.ts, 40, 62))
>Test : Symbol(Test, Decl(genericCallInferenceInConditionalTypes1.ts, 31, 2))
>component : Symbol(component, Decl(genericCallInferenceInConditionalTypes1.ts, 42, 21))
>ComponentWithForwardRef : Symbol(ComponentWithForwardRef, Decl(genericCallInferenceInConditionalTypes1.ts, 24, 5))

// same as ComponentWithForwardRef above but using a resolved signature instead of a direct inferred result of `forwardRef`
declare const ComponentWithForwardRef2: <T extends FunctionComponent<any>>(
>ComponentWithForwardRef2 : Symbol(ComponentWithForwardRef2, Decl(genericCallInferenceInConditionalTypes1.ts, 45, 13))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 45, 41))
>FunctionComponent : Symbol(FunctionComponent, Decl(genericCallInferenceInConditionalTypes1.ts, 4, 2))

props: PropsWithoutRef<ComponentProps<T>> & {
>props : Symbol(props, Decl(genericCallInferenceInConditionalTypes1.ts, 45, 75))
>PropsWithoutRef : Symbol(PropsWithoutRef, Decl(genericCallInferenceInConditionalTypes1.ts, 9, 48))
>ComponentProps : Symbol(ComponentProps, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 50))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 45, 41))

className?: string;
>className : Symbol(className, Decl(genericCallInferenceInConditionalTypes1.ts, 46, 47))

as?: T | undefined;
>as : Symbol(as, Decl(genericCallInferenceInConditionalTypes1.ts, 47, 23))
>T : Symbol(T, Decl(genericCallInferenceInConditionalTypes1.ts, 45, 41))

} & {
ref?: Ref<HTMLElement> | undefined;
>ref : Symbol(ref, Decl(genericCallInferenceInConditionalTypes1.ts, 49, 7))
>Ref : Symbol(Ref, Decl(genericCallInferenceInConditionalTypes1.ts, 0, 0))
>HTMLElement : Symbol(HTMLElement, Decl(lib.dom.d.ts, --, --), Decl(lib.dom.d.ts, --, --))

},
) => unknown;

type Result3 = ComponentProps<typeof ComponentWithForwardRef2>;
>Result3 : Symbol(Result3, Decl(genericCallInferenceInConditionalTypes1.ts, 52, 13))
>ComponentProps : Symbol(ComponentProps, Decl(genericCallInferenceInConditionalTypes1.ts, 6, 50))
>ComponentWithForwardRef2 : Symbol(ComponentWithForwardRef2, Decl(genericCallInferenceInConditionalTypes1.ts, 45, 13))

type Result4 = Test<{ component: typeof ComponentWithForwardRef2 }>;
>Result4 : Symbol(Result4, Decl(genericCallInferenceInConditionalTypes1.ts, 54, 63))
>Test : Symbol(Test, Decl(genericCallInferenceInConditionalTypes1.ts, 31, 2))
>component : Symbol(component, Decl(genericCallInferenceInConditionalTypes1.ts, 55, 21))
>ComponentWithForwardRef2 : Symbol(ComponentWithForwardRef2, Decl(genericCallInferenceInConditionalTypes1.ts, 45, 13))

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