Fix lookup of optional methods in declaration emit (microsoft#32094)

Author: weswigham

src/compiler/checker.ts

@@ -4093,7 +4093,7 @@ namespace ts {
                 context.enclosingDeclaration = saveEnclosingDeclaration;
                 const optionalToken = propertySymbol.flags & SymbolFlags.Optional ? createToken(SyntaxKind.QuestionToken) : undefined;
                 if (propertySymbol.flags & (SymbolFlags.Function | SymbolFlags.Method) && !getPropertiesOfObjectType(propertyType).length && !isReadonlySymbol(propertySymbol)) {
-                    const signatures = getSignaturesOfType(propertyType, SignatureKind.Call);
+                    const signatures = getSignaturesOfType(filterType(propertyType, t => !(t.flags & TypeFlags.Undefined)), SignatureKind.Call);
                     for (const signature of signatures) {
                         const methodDeclaration = <MethodSignature>signatureToSignatureDeclarationHelper(signature, SyntaxKind.MethodSignature, context);
                         methodDeclaration.name = propertyName;

tests/baselines/reference/declarationEmitOptionalMethod.js

@@ -0,0 +1,23 @@
+//// [declarationEmitOptionalMethod.ts]
+export const Foo = (opts: {
+    a?(): void,
+    b?: () => void,
+}): {
+    c?(): void,
+    d?: () => void,
+} => ({  });
+
+//// [declarationEmitOptionalMethod.js]
+"use strict";
+exports.__esModule = true;
+exports.Foo = function (opts) { return ({}); };
+
+
+//// [declarationEmitOptionalMethod.d.ts]
+export declare const Foo: (opts: {
+    a?(): void;
+    b?: (() => void) | undefined;
+}) => {
+    c?(): void;
+    d?: (() => void) | undefined;
+};

tests/baselines/reference/declarationEmitOptionalMethod.symbols

@@ -0,0 +1,19 @@
+=== tests/cases/compiler/declarationEmitOptionalMethod.ts ===
+export const Foo = (opts: {
+>Foo : Symbol(Foo, Decl(declarationEmitOptionalMethod.ts, 0, 12))
+>opts : Symbol(opts, Decl(declarationEmitOptionalMethod.ts, 0, 20))
+
+    a?(): void,
+>a : Symbol(a, Decl(declarationEmitOptionalMethod.ts, 0, 27))
+
+    b?: () => void,
+>b : Symbol(b, Decl(declarationEmitOptionalMethod.ts, 1, 15))
+
+}): {
+    c?(): void,
+>c : Symbol(c, Decl(declarationEmitOptionalMethod.ts, 3, 5))
+
+    d?: () => void,
+>d : Symbol(d, Decl(declarationEmitOptionalMethod.ts, 4, 15))
+
+} => ({  });

tests/baselines/reference/declarationEmitOptionalMethod.types

@@ -0,0 +1,23 @@
+=== tests/cases/compiler/declarationEmitOptionalMethod.ts ===
+export const Foo = (opts: {
+>Foo : (opts: { a?(): void; b?: (() => void) | undefined; }) => { c?(): void; d?: (() => void) | undefined; }
+>(opts: {    a?(): void,    b?: () => void,}): {    c?(): void,    d?: () => void,} => ({  }) : (opts: { a?(): void; b?: (() => void) | undefined; }) => { c?(): void; d?: (() => void) | undefined; }
+>opts : { a?(): void; b?: (() => void) | undefined; }
+
+    a?(): void,
+>a : (() => void) | undefined
+
+    b?: () => void,
+>b : (() => void) | undefined
+
+}): {
+    c?(): void,
+>c : (() => void) | undefined
+
+    d?: () => void,
+>d : (() => void) | undefined
+
+} => ({  });
+>({  }) : {}
+>{  } : {}
+

tests/baselines/reference/definiteAssignmentAssertionsWithObjectShortHand.js

@@ -20,4 +20,6 @@ declare const a: string | undefined;
 declare const foo: {
     a: string;
 };
-declare const bar: {};
+declare const bar: {
+    a?(): void;
+};

tests/baselines/reference/definiteAssignmentAssertionsWithObjectShortHand.types

@@ -9,8 +9,8 @@ const foo = { a! }
 >a : string
 
 const bar = {
->bar : {}
->{    a ? () { }} : {}
+>bar : { a?(): void; }
+>{    a ? () { }} : { a?(): void; }
 
     a ? () { }
 >a : (() => void) | undefined

tests/baselines/reference/strictTypeofUnionNarrowing.types

@@ -52,15 +52,15 @@ function stringify3(anything: unknown | undefined): string { // should simplify
 }
 
 function stringify4(anything: { toString?(): string } | undefined): string {
->stringify4 : (anything: {} | undefined) => string
->anything : {} | undefined
+>stringify4 : (anything: { toString?(): string; } | undefined) => string
+>anything : { toString?(): string; } | undefined
 >toString : (() => string) | undefined
 
     return typeof anything === "string" ? anything.toUpperCase() : "";
 >typeof anything === "string" ? anything.toUpperCase() : "" : string
 >typeof anything === "string" : boolean
 >typeof anything : "string" | "number" | "bigint" | "boolean" | "symbol" | "undefined" | "object" | "function"
->anything : {} | undefined
+>anything : { toString?(): string; } | undefined
 >"string" : "string"
 >anything.toUpperCase() : string
 >anything.toUpperCase : () => string

tests/baselines/reference/typeFromContextualThisType.types

@@ -1,7 +1,7 @@
 === tests/cases/conformance/salsa/bug25926.js ===
 /** @type {{ a(): void; b?(n: number): number; }} */
 const o1 = {
->o1 : { a(): void; }
+>o1 : { a(): void; b?(n: number): number; }
 >{    a() {        this.b = n => n;    }} : { a(): void; }
 
     a() {
@@ -10,7 +10,7 @@ const o1 = {
         this.b = n => n;
 >this.b = n => n : (n: number) => number
 >this.b : ((n: number) => number) | undefined
->this : { a(): void; }
+>this : { a(): void; b?(n: number): number; }
 >b : ((n: number) => number) | undefined
 >n => n : (n: number) => number
 >n : number
@@ -20,7 +20,7 @@ const o1 = {
 
 /** @type {{ d(): void; e?(n: number): number; f?(n: number): number; g?: number }} */
 const o2 = {
->o2 : { d(): void; g?: number | undefined; }
+>o2 : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >{    d() {        this.e = this.f = m => this.g || m;    }} : { d(): void; }
 
     d() {
@@ -29,17 +29,17 @@ const o2 = {
         this.e = this.f = m => this.g || m;
 >this.e = this.f = m => this.g || m : (m: number) => number
 >this.e : ((n: number) => number) | undefined
->this : { d(): void; g?: number | undefined; }
+>this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >e : ((n: number) => number) | undefined
 >this.f = m => this.g || m : (m: number) => number
 >this.f : ((n: number) => number) | undefined
->this : { d(): void; g?: number | undefined; }
+>this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >f : ((n: number) => number) | undefined
 >m => this.g || m : (m: number) => number
 >m : number
 >this.g || m : number
 >this.g : number | undefined
->this : { d(): void; g?: number | undefined; }
+>this : { d(): void; e?(n: number): number; f?(n: number): number; g?: number | undefined; }
 >g : number | undefined
 >m : number
     }

tests/cases/compiler/declarationEmitOptionalMethod.ts

@@ -0,0 +1,9 @@
+// @declaration: true
+// @strictNullChecks: true
+export const Foo = (opts: {
+    a?(): void,
+    b?: () => void,
+}): {
+    c?(): void,
+    d?: () => void,
+} => ({  });