Fix declaration emit renaming a method's shadowed type parameter to the outer generic (#3761)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: jakebailey <5341706+jakebailey@users.noreply.github.com>

Author: Copilot

internal/binder/nameresolver.go

@@ -56,8 +56,18 @@ loop:
 					// - Type parameters of a function are in scope in the entire function declaration, including the parameter
 					//   list and return type. However, local types are only in scope in the function body.
 					// - parameters are only in the scope of function body
-					if meaning&result.Flags&ast.SymbolFlagsType != 0 {
-						useResult = result.Flags&ast.SymbolFlagsTypeParameter != 0 && (lastLocation == location.Type() || ast.IsParameterLike(lastLocation))
+					// This restriction does not apply to JSDoc comment types because they are parented
+					// at a higher level than type parameters would normally be
+					if meaning&result.Flags&ast.SymbolFlagsType != 0 && lastLocation.Kind != ast.KindJSDoc {
+						// type parameters are visible in parameter list, return type and type parameter list.
+						// Synthetic fake scopes are added for signatures so type parameters are accessible from them.
+						useResult = result.Flags&ast.SymbolFlagsTypeParameter != 0 &&
+							(lastLocation.Flags&ast.NodeFlagsSynthesized != 0 ||
+								lastLocation == location.Type() ||
+								lastLocation.Kind == ast.KindParameter ||
+								lastLocation.Kind == ast.KindJSDocParameterTag ||
+								lastLocation.Kind == ast.KindJSDocReturnTag ||
+								lastLocation.Kind == ast.KindTypeParameter)
 					}
 					if meaning&result.Flags&ast.SymbolFlagsVariable != 0 {
 						// expression inside parameter will lookup as normal variable scope when targeting es2015+

testdata/baselines/reference/compiler/declarationEmitMethodShadowsClassTypeParameter.js

@@ -0,0 +1,22 @@
+//// [tests/cases/compiler/declarationEmitMethodShadowsClassTypeParameter.ts] ////
+
+//// [declarationEmitMethodShadowsClassTypeParameter.ts]
+export class Outer<Table> {
+    method<Table, R>(r: R) {
+        return null as Table | null;
+    }
+}
+
+
+//// [declarationEmitMethodShadowsClassTypeParameter.js]
+export class Outer {
+    method(r) {
+        return null;
+    }
+}
+
+
+//// [declarationEmitMethodShadowsClassTypeParameter.d.ts]
+export declare class Outer<Table> {
+    method<Table, R>(r: R): Table | null;
+}

testdata/baselines/reference/compiler/declarationEmitMethodShadowsClassTypeParameter.symbols

@@ -0,0 +1,19 @@
+//// [tests/cases/compiler/declarationEmitMethodShadowsClassTypeParameter.ts] ////
+
+=== declarationEmitMethodShadowsClassTypeParameter.ts ===
+export class Outer<Table> {
+>Outer : Symbol(Outer, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 0, 0))
+>Table : Symbol(Table, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 0, 19))
+
+    method<Table, R>(r: R) {
+>method : Symbol(Outer.method, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 0, 27))
+>Table : Symbol(Table, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 1, 11))
+>R : Symbol(R, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 1, 17))
+>r : Symbol(r, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 1, 21))
+>R : Symbol(R, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 1, 17))
+
+        return null as Table | null;
+>Table : Symbol(Table, Decl(declarationEmitMethodShadowsClassTypeParameter.ts, 1, 11))
+    }
+}
+

testdata/baselines/reference/compiler/declarationEmitMethodShadowsClassTypeParameter.types

@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/declarationEmitMethodShadowsClassTypeParameter.ts] ////
+
+=== declarationEmitMethodShadowsClassTypeParameter.ts ===
+export class Outer<Table> {
+>Outer : Outer<Table>
+
+    method<Table, R>(r: R) {
+>method : <Table, R>(r: R) => Table | null
+>r : R
+
+        return null as Table | null;
+>null as Table | null : Table | null
+    }
+}
+

testdata/baselines/reference/compiler/jsExportsImportedIntoTsxLosesTypeInfo.types

@@ -124,15 +124,15 @@ export function compose<F extends Function>(f: F): F;
 >f : F
 
 export function compose<A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C;
->compose : { (): <R>(a: R) => R; <F extends Function>(f: F): F; <A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C; <A, B, C, D>(f1: (c: C) => D, f2: (b: B) => C, f3: (a: A) => B): (a: A) => D; <R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R; <R>(...funcs: Function[]): (...args: any[]) => R; }
+>compose : { (): <R>(a: R) => R; <F extends Function>(f: F): F; <A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C; <A_1, B_1, C_1, D>(f1: (c: C_1) => D, f2: (b: B_1) => C_1, f3: (a: A_1) => B_1): (a: A_1) => D; <R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R; <R>(...funcs: Function[]): (...args: any[]) => R; }
 >f1 : (b: B) => C
 >b : B
 >f2 : (a: A) => B
 >a : A
 >a : A
 
 export function compose<A, B, C, D>(
->compose : { (): <R>(a: R) => R; <F extends Function>(f: F): F; <A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C; <A, B, C, D>(f1: (c: C) => D, f2: (b: B) => C, f3: (a: A) => B): (a: A) => D; <R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R; <R>(...funcs: Function[]): (...args: any[]) => R; }
+>compose : { (): <R>(a: R) => R; <F extends Function>(f: F): F; <A_1, B_1, C_1>(f1: (b: B_1) => C_1, f2: (a: A_1) => B_1): (a: A_1) => C_1; <A, B, C, D>(f1: (c: C) => D, f2: (b: B) => C, f3: (a: A) => B): (a: A) => D; <R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R; <R>(...funcs: Function[]): (...args: any[]) => R; }
 
     f1: (c: C) => D,
 >f1 : (c: C) => D
@@ -150,14 +150,14 @@ export function compose<A, B, C, D>(
 >a : A
 
 export function compose<R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R;
->compose : { (): <R>(a: R) => R; <F extends Function>(f: F): F; <A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C; <A, B, C, D>(f1: (c: C) => D, f2: (b: B) => C, f3: (a: A) => B): (a: A) => D; <R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R; <R>(...funcs: Function[]): (...args: any[]) => R; }
+>compose : { (): <R_1>(a: R_1) => R_1; <F extends Function>(f: F): F; <A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C; <A, B, C, D>(f1: (c: C) => D, f2: (b: B) => C, f3: (a: A) => B): (a: A) => D; <R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R; <R_1>(...funcs: Function[]): (...args: any[]) => R_1; }
 >f1 : (a: any) => R
 >a : any
 >funcs : Function[]
 >args : any[]
 
 export function compose<R>(...funcs: Function[]): (...args: any[]) => R;
->compose : { (): <R>(a: R) => R; <F extends Function>(f: F): F; <A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C; <A, B, C, D>(f1: (c: C) => D, f2: (b: B) => C, f3: (a: A) => B): (a: A) => D; <R>(f1: (a: any) => R, ...funcs: Function[]): (...args: any[]) => R; <R>(...funcs: Function[]): (...args: any[]) => R; }
+>compose : { (): <R_1>(a: R_1) => R_1; <F extends Function>(f: F): F; <A, B, C>(f1: (b: B) => C, f2: (a: A) => B): (a: A) => C; <A, B, C, D>(f1: (c: C) => D, f2: (b: B) => C, f3: (a: A) => B): (a: A) => D; <R_1>(f1: (a: any) => R_1, ...funcs: Function[]): (...args: any[]) => R_1; <R>(...funcs: Function[]): (...args: any[]) => R; }
 >funcs : Function[]
 >args : any[]
 

testdata/baselines/reference/submodule/compiler/asyncFunctionsAndStrictNullChecks.types

@@ -4,7 +4,7 @@
 declare namespace Windows.Foundation {
     interface IPromise<TResult> {
         then<U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>;
->then : { <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; }
+>then : { <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U_1>(success?: (value: TResult) => IPromise<U_1>, error?: (error: any) => U_1, progress?: (progress: any) => void): IPromise<U_1>; <U_1>(success?: (value: TResult) => U_1, error?: (error: any) => IPromise<U_1>, progress?: (progress: any) => void): IPromise<U_1>; <U_1>(success?: (value: TResult) => U_1, error?: (error: any) => U_1, progress?: (progress: any) => void): IPromise<U_1>; }
 >success : ((value: TResult) => IPromise<U>) | undefined
 >value : TResult
 >error : ((error: any) => IPromise<U>) | undefined
@@ -13,7 +13,7 @@ declare namespace Windows.Foundation {
 >progress : any
 
         then<U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>;
->then : { <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; }
+>then : { <U_1>(success?: (value: TResult) => IPromise<U_1>, error?: (error: any) => IPromise<U_1>, progress?: (progress: any) => void): IPromise<U_1>; <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; <U_1>(success?: (value: TResult) => U_1, error?: (error: any) => IPromise<U_1>, progress?: (progress: any) => void): IPromise<U_1>; <U_1>(success?: (value: TResult) => U_1, error?: (error: any) => U_1, progress?: (progress: any) => void): IPromise<U_1>; }
 >success : ((value: TResult) => IPromise<U>) | undefined
 >value : TResult
 >error : ((error: any) => U) | undefined
@@ -22,7 +22,7 @@ declare namespace Windows.Foundation {
 >progress : any
 
         then<U>(success?: (value: TResult) => U, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>;
->then : { <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; }
+>then : { <U_1>(success?: (value: TResult) => IPromise<U_1>, error?: (error: any) => IPromise<U_1>, progress?: (progress: any) => void): IPromise<U_1>; <U_1>(success?: (value: TResult) => IPromise<U_1>, error?: (error: any) => U_1, progress?: (progress: any) => void): IPromise<U_1>; <U>(success?: (value: TResult) => U, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U_1>(success?: (value: TResult) => U_1, error?: (error: any) => U_1, progress?: (progress: any) => void): IPromise<U_1>; }
 >success : ((value: TResult) => U) | undefined
 >value : TResult
 >error : ((error: any) => IPromise<U>) | undefined
@@ -31,7 +31,7 @@ declare namespace Windows.Foundation {
 >progress : any
 
         then<U>(success?: (value: TResult) => U, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>;
->then : { <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => IPromise<U>, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => IPromise<U>, progress?: (progress: any) => void): IPromise<U>; <U>(success?: (value: TResult) => U, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; }
+>then : { <U_1>(success?: (value: TResult) => IPromise<U_1>, error?: (error: any) => IPromise<U_1>, progress?: (progress: any) => void): IPromise<U_1>; <U_1>(success?: (value: TResult) => IPromise<U_1>, error?: (error: any) => U_1, progress?: (progress: any) => void): IPromise<U_1>; <U_1>(success?: (value: TResult) => U_1, error?: (error: any) => IPromise<U_1>, progress?: (progress: any) => void): IPromise<U_1>; <U>(success?: (value: TResult) => U, error?: (error: any) => U, progress?: (progress: any) => void): IPromise<U>; }
 >success : ((value: TResult) => U) | undefined
 >value : TResult
 >error : ((error: any) => U) | undefined