When reusing input type nodes, only instantiate the type for comparison if it is a this type (#42584)

src/compiler/checker.ts

@@ -6005,10 +6005,14 @@ namespace ts {
             function serializeReturnTypeForSignature(context: NodeBuilderContext, type: Type, signature: Signature, includePrivateSymbol?: (s: Symbol) => void, bundled?: boolean) {
                 if (type !== errorType && context.enclosingDeclaration) {
                     const annotation = signature.declaration && getEffectiveReturnTypeNode(signature.declaration);
-                    if (!!findAncestor(annotation, n => n === context.enclosingDeclaration) && annotation && instantiateType(getTypeFromTypeNode(annotation), signature.mapper) === type && existingTypeNodeIsNotReferenceOrIsReferenceWithCompatibleTypeArgumentCount(annotation, type)) {
-                        const result = serializeExistingTypeNode(context, annotation, includePrivateSymbol, bundled);
-                        if (result) {
-                            return result;
+                    if (!!findAncestor(annotation, n => n === context.enclosingDeclaration) && annotation) {
+                        const annotated = getTypeFromTypeNode(annotation);
+                        const thisInstantiated = annotated.flags & TypeFlags.TypeParameter && (annotated as TypeParameter).isThisType ? instantiateType(annotated, signature.mapper) : annotated;
+                        if (thisInstantiated === type && existingTypeNodeIsNotReferenceOrIsReferenceWithCompatibleTypeArgumentCount(annotation, type)) {
+                            const result = serializeExistingTypeNode(context, annotation, includePrivateSymbol, bundled);
+                            if (result) {
+                                return result;
+                            }
                         }
                     }
                 }

tests/baselines/reference/declarationEmitOverloadedPrivateInference.js

@@ -0,0 +1,56 @@
+//// [declarationEmitOverloadedPrivateInference.ts]
+function noArgs(): string {
+    return null as any;
+}
+
+function oneArg(input: string): string {
+    return null as any;
+}
+
+export class Wrapper {
+    private proxy<T, U>(fn: (options: T) => U): (options: T) => U;
+    private proxy<T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U;
+
+    private proxy<T, U>(fn: (options: T) => U) {
+        return null as any;
+    }
+
+    public Proxies = {
+        Failure: this.proxy(noArgs, true),
+        Success: this.proxy(oneArg),
+    };
+}
+
+//// [declarationEmitOverloadedPrivateInference.js]
+"use strict";
+exports.__esModule = true;
+exports.Wrapper = void 0;
+function noArgs() {
+    return null;
+}
+function oneArg(input) {
+    return null;
+}
+var Wrapper = /** @class */ (function () {
+    function Wrapper() {
+        this.Proxies = {
+            Failure: this.proxy(noArgs, true),
+            Success: this.proxy(oneArg)
+        };
+    }
+    Wrapper.prototype.proxy = function (fn) {
+        return null;
+    };
+    return Wrapper;
+}());
+exports.Wrapper = Wrapper;
+
+
+//// [declarationEmitOverloadedPrivateInference.d.ts]
+export declare class Wrapper {
+    private proxy;
+    Proxies: {
+        Failure: (options?: unknown) => string;
+        Success: (options: string) => string;
+    };
+}

tests/baselines/reference/declarationEmitOverloadedPrivateInference.symbols

@@ -0,0 +1,73 @@
+=== tests/cases/compiler/declarationEmitOverloadedPrivateInference.ts ===
+function noArgs(): string {
+>noArgs : Symbol(noArgs, Decl(declarationEmitOverloadedPrivateInference.ts, 0, 0))
+
+    return null as any;
+}
+
+function oneArg(input: string): string {
+>oneArg : Symbol(oneArg, Decl(declarationEmitOverloadedPrivateInference.ts, 2, 1))
+>input : Symbol(input, Decl(declarationEmitOverloadedPrivateInference.ts, 4, 16))
+
+    return null as any;
+}
+
+export class Wrapper {
+>Wrapper : Symbol(Wrapper, Decl(declarationEmitOverloadedPrivateInference.ts, 6, 1))
+
+    private proxy<T, U>(fn: (options: T) => U): (options: T) => U;
+>proxy : Symbol(Wrapper.proxy, Decl(declarationEmitOverloadedPrivateInference.ts, 8, 22), Decl(declarationEmitOverloadedPrivateInference.ts, 9, 66), Decl(declarationEmitOverloadedPrivateInference.ts, 10, 82))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 20))
+>fn : Symbol(fn, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 24))
+>options : Symbol(options, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 29))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 20))
+>options : Symbol(options, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 49))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 9, 20))
+
+    private proxy<T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U;
+>proxy : Symbol(Wrapper.proxy, Decl(declarationEmitOverloadedPrivateInference.ts, 8, 22), Decl(declarationEmitOverloadedPrivateInference.ts, 9, 66), Decl(declarationEmitOverloadedPrivateInference.ts, 10, 82))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 20))
+>fn : Symbol(fn, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 24))
+>options : Symbol(options, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 29))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 20))
+>noArgs : Symbol(noArgs, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 47))
+>options : Symbol(options, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 64))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 10, 20))
+
+    private proxy<T, U>(fn: (options: T) => U) {
+>proxy : Symbol(Wrapper.proxy, Decl(declarationEmitOverloadedPrivateInference.ts, 8, 22), Decl(declarationEmitOverloadedPrivateInference.ts, 9, 66), Decl(declarationEmitOverloadedPrivateInference.ts, 10, 82))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 12, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 12, 20))
+>fn : Symbol(fn, Decl(declarationEmitOverloadedPrivateInference.ts, 12, 24))
+>options : Symbol(options, Decl(declarationEmitOverloadedPrivateInference.ts, 12, 29))
+>T : Symbol(T, Decl(declarationEmitOverloadedPrivateInference.ts, 12, 18))
+>U : Symbol(U, Decl(declarationEmitOverloadedPrivateInference.ts, 12, 20))
+
+        return null as any;
+    }
+
+    public Proxies = {
+>Proxies : Symbol(Wrapper.Proxies, Decl(declarationEmitOverloadedPrivateInference.ts, 14, 5))
+
+        Failure: this.proxy(noArgs, true),
+>Failure : Symbol(Failure, Decl(declarationEmitOverloadedPrivateInference.ts, 16, 22))
+>this.proxy : Symbol(Wrapper.proxy, Decl(declarationEmitOverloadedPrivateInference.ts, 8, 22), Decl(declarationEmitOverloadedPrivateInference.ts, 9, 66), Decl(declarationEmitOverloadedPrivateInference.ts, 10, 82))
+>this : Symbol(Wrapper, Decl(declarationEmitOverloadedPrivateInference.ts, 6, 1))
+>proxy : Symbol(Wrapper.proxy, Decl(declarationEmitOverloadedPrivateInference.ts, 8, 22), Decl(declarationEmitOverloadedPrivateInference.ts, 9, 66), Decl(declarationEmitOverloadedPrivateInference.ts, 10, 82))
+>noArgs : Symbol(noArgs, Decl(declarationEmitOverloadedPrivateInference.ts, 0, 0))
+
+        Success: this.proxy(oneArg),
+>Success : Symbol(Success, Decl(declarationEmitOverloadedPrivateInference.ts, 17, 42))
+>this.proxy : Symbol(Wrapper.proxy, Decl(declarationEmitOverloadedPrivateInference.ts, 8, 22), Decl(declarationEmitOverloadedPrivateInference.ts, 9, 66), Decl(declarationEmitOverloadedPrivateInference.ts, 10, 82))
+>this : Symbol(Wrapper, Decl(declarationEmitOverloadedPrivateInference.ts, 6, 1))
+>proxy : Symbol(Wrapper.proxy, Decl(declarationEmitOverloadedPrivateInference.ts, 8, 22), Decl(declarationEmitOverloadedPrivateInference.ts, 9, 66), Decl(declarationEmitOverloadedPrivateInference.ts, 10, 82))
+>oneArg : Symbol(oneArg, Decl(declarationEmitOverloadedPrivateInference.ts, 2, 1))
+
+    };
+}

tests/baselines/reference/declarationEmitOverloadedPrivateInference.types

@@ -0,0 +1,68 @@
+=== tests/cases/compiler/declarationEmitOverloadedPrivateInference.ts ===
+function noArgs(): string {
+>noArgs : () => string
+
+    return null as any;
+>null as any : any
+>null : null
+}
+
+function oneArg(input: string): string {
+>oneArg : (input: string) => string
+>input : string
+
+    return null as any;
+>null as any : any
+>null : null
+}
+
+export class Wrapper {
+>Wrapper : Wrapper
+
+    private proxy<T, U>(fn: (options: T) => U): (options: T) => U;
+>proxy : { <T, U>(fn: (options: T) => U): (options: T) => U; <T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U; }
+>fn : (options: T) => U
+>options : T
+>options : T
+
+    private proxy<T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U;
+>proxy : { <T, U>(fn: (options: T) => U): (options: T) => U; <T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U; }
+>fn : (options?: T) => U
+>options : T
+>noArgs : true
+>true : true
+>options : T
+
+    private proxy<T, U>(fn: (options: T) => U) {
+>proxy : { <T, U>(fn: (options: T) => U): (options: T) => U; <T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U; }
+>fn : (options: T) => U
+>options : T
+
+        return null as any;
+>null as any : any
+>null : null
+    }
+
+    public Proxies = {
+>Proxies : { Failure: (options?: unknown) => string; Success: (options: string) => string; }
+>{        Failure: this.proxy(noArgs, true),        Success: this.proxy(oneArg),    } : { Failure: (options?: unknown) => string; Success: (options: string) => string; }
+
+        Failure: this.proxy(noArgs, true),
+>Failure : (options?: unknown) => string
+>this.proxy(noArgs, true) : (options?: unknown) => string
+>this.proxy : { <T, U>(fn: (options: T) => U): (options: T) => U; <T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U; }
+>this : this
+>proxy : { <T, U>(fn: (options: T) => U): (options: T) => U; <T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U; }
+>noArgs : () => string
+>true : true
+
+        Success: this.proxy(oneArg),
+>Success : (options: string) => string
+>this.proxy(oneArg) : (options: string) => string
+>this.proxy : { <T, U>(fn: (options: T) => U): (options: T) => U; <T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U; }
+>this : this
+>proxy : { <T, U>(fn: (options: T) => U): (options: T) => U; <T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U; }
+>oneArg : (input: string) => string
+
+    };
+}

tests/baselines/reference/declarationsWithRecursiveInternalTypesProduceUniqueTypeParams.types

@@ -38,13 +38,13 @@ export const updateIfChanged = <T>(t: T) => {
 >newU : U
 
         return Object.assign(
->Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set }) : (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => U) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => U) => T; set: (newU: Value<K, U>) => T; }) & { map: (updater: (u: U) => U) => T; set: (newU: U) => T; }
+>Object.assign(            <K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }),            { map: (updater: (u: U) => U) => set(updater(u)), set }) : (<K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }) & { map: (updater: (u: U) => U) => T; set: (newU: U) => T; }
 >Object.assign : { <T, U>(target: T, source: U): T & U; <T, U, V>(target: T, source1: U, source2: V): T & U & V; <T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
 >Object : ObjectConstructor
 >assign : { <T, U>(target: T, source: U): T & U; <T, U, V>(target: T, source1: U, source2: V): T & U & V; <T, U, V, W>(target: T, source1: U, source2: V, source3: W): T & U & V & W; (target: object, ...sources: any[]): any; }
 
             <K extends Key<U>>(key: K) =>
-><K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }) : <K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => U) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => U) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => U) => T; set: (newU: Value<K, U>) => T; }
+><K extends Key<U>>(key: K) =>                reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {                    return update(Object.assign(Array.isArray(u) ? [] : {}, u, { [key]: v }));                }) : <K extends keyof U>(key: K) => (<K extends keyof Value<K, U>>(key: K) => (<K extends keyof Value<K, Value<K, U>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, U>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, U>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>(key: K) => (<K extends keyof Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>(key: K) => any & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, Value<K, U>>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, Value<K, U>>>>) => Value<K, Value<K, Value<K, Value<K, U>>>>) => T; set: (newU: Value<K, Value<K, Value<K, Value<K, U>>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, Value<K, U>>>) => Value<K, Value<K, Value<K, U>>>) => T; set: (newU: Value<K, Value<K, Value<K, U>>>) => T; }) & { map: (updater: (u: Value<K, Value<K, U>>) => Value<K, Value<K, U>>) => T; set: (newU: Value<K, Value<K, U>>) => T; }) & { map: (updater: (u: Value<K, U>) => Value<K, U>) => T; set: (newU: Value<K, U>) => T; }
 >key : K
 
                 reduce<Value<K, U>>(u[key as keyof U] as Value<K, U>, (v: Value<K, U>) => {

tests/baselines/reference/jsDeclarationsInterfaces.js

@@ -135,10 +135,10 @@ export interface B {
 export interface C<T_1, U_1> {
     new (): string;
     new (x: T_1): U_1;
-    new <Q_6>(x: Q_6): T_1 & Q_6;
+    new <Q_4>(x: Q_4): T_1 & Q_4;
     (): number;
     (x: T_1): U_1;
-    <Q_4>(x: Q_4): T_1 & Q_4;
+    <Q_3>(x: Q_3): T_1 & Q_3;
     field: T_1 & U_1;
     optionalField?: T_1;
     readonly readonlyField: T_1 & U_1;

tests/cases/compiler/declarationEmitOverloadedPrivateInference.ts

@@ -0,0 +1,22 @@
+// @declaration: true
+function noArgs(): string {
+    return null as any;
+}
+
+function oneArg(input: string): string {
+    return null as any;
+}
+
+export class Wrapper {
+    private proxy<T, U>(fn: (options: T) => U): (options: T) => U;
+    private proxy<T, U>(fn: (options?: T) => U, noArgs: true): (options?: T) => U;
+
+    private proxy<T, U>(fn: (options: T) => U) {
+        return null as any;
+    }
+
+    public Proxies = {
+        Failure: this.proxy(noArgs, true),
+        Success: this.proxy(oneArg),
+    };
+}