Fix crash in declaration emit with nested binding patterns (#63154)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: DanielRosenwasser <972891+DanielRosenwasser@users.noreply.github.com>

src/compiler/transformers/declarations.ts

@@ -1621,11 +1621,12 @@ export function transformDeclarations(context: TransformationContext): Transform
                                 if (isOmittedExpression(elem)) continue;
                                 if (isBindingPattern(elem.name)) {
                                     elems = concatenate(elems, walkBindingPattern(elem.name));
+                                    continue;
                                 }
                                 elems = elems || [];
                                 elems.push(factory.createPropertyDeclaration(
                                     ensureModifiers(param),
-                                    elem.name as Identifier,
+                                    elem.name,
                                     /*questionOrExclamationToken*/ undefined,
                                     ensureType(elem),
                                     /*initializer*/ undefined,

tests/baselines/reference/declarationEmitNestedBindingPattern.errors.txt

@@ -0,0 +1,81 @@
+declarationEmitNestedBindingPattern.ts(3,17): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(8,17): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(13,17): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(18,17): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(23,17): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(28,17): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(34,9): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(35,9): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(41,17): error TS1187: A parameter property may not be declared using a binding pattern.
+declarationEmitNestedBindingPattern.ts(46,17): error TS1187: A parameter property may not be declared using a binding pattern.
+
+
+==== declarationEmitNestedBindingPattern.ts (10 errors) ====
+    // Nested array binding pattern
+    export class C1 {
+        constructor(public [[x]]: any[]) {}
+                    ~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    
+    // Nested object binding pattern
+    export class C2 {
+        constructor(public [{y}]: any[]) {}
+                    ~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    
+    // Multiple levels of array nesting
+    export class C3 {
+        constructor(public [[[z]]]: any[]) {}
+                    ~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    
+    // Mixed array and object nesting
+    export class C4 {
+        constructor(public [{a: [b]}]: any[]) {}
+                    ~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    
+    // Object with nested array
+    export class C5 {
+        constructor(public {prop: [c]}: any) {}
+                    ~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    
+    // Object with multiple nested levels
+    export class C6 {
+        constructor(public {prop: {nested: [d]}}: any) {}
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    
+    // Multiple parameters with nested patterns
+    export class C7 {
+        constructor(
+            public [[e]]: any[],
+            ~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+            public [{f}]: any[]
+            ~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+        ) {}
+    }
+    
+    // Nested pattern with rest element
+    export class C8 {
+        constructor(public [[g, ...rest]]: any[]) {}
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    
+    // Complex nested pattern
+    export class C9 {
+        constructor(public [[h, i], {j, k: [l]}]: any) {}
+                    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1187: A parameter property may not be declared using a binding pattern.
+    }
+    

tests/baselines/reference/declarationEmitNestedBindingPattern.js

@@ -0,0 +1,142 @@
+//// [tests/cases/compiler/declarationEmitNestedBindingPattern.ts] ////
+
+//// [declarationEmitNestedBindingPattern.ts]
+// Nested array binding pattern
+export class C1 {
+    constructor(public [[x]]: any[]) {}
+}
+
+// Nested object binding pattern
+export class C2 {
+    constructor(public [{y}]: any[]) {}
+}
+
+// Multiple levels of array nesting
+export class C3 {
+    constructor(public [[[z]]]: any[]) {}
+}
+
+// Mixed array and object nesting
+export class C4 {
+    constructor(public [{a: [b]}]: any[]) {}
+}
+
+// Object with nested array
+export class C5 {
+    constructor(public {prop: [c]}: any) {}
+}
+
+// Object with multiple nested levels
+export class C6 {
+    constructor(public {prop: {nested: [d]}}: any) {}
+}
+
+// Multiple parameters with nested patterns
+export class C7 {
+    constructor(
+        public [[e]]: any[],
+        public [{f}]: any[]
+    ) {}
+}
+
+// Nested pattern with rest element
+export class C8 {
+    constructor(public [[g, ...rest]]: any[]) {}
+}
+
+// Complex nested pattern
+export class C9 {
+    constructor(public [[h, i], {j, k: [l]}]: any) {}
+}
+
+
+//// [declarationEmitNestedBindingPattern.js]
+// Nested array binding pattern
+export class C1 {
+    constructor([[x]]) {
+    }
+}
+// Nested object binding pattern
+export class C2 {
+    constructor([{ y }]) {
+    }
+}
+// Multiple levels of array nesting
+export class C3 {
+    constructor([[[z]]]) {
+    }
+}
+// Mixed array and object nesting
+export class C4 {
+    constructor([{ a: [b] }]) {
+    }
+}
+// Object with nested array
+export class C5 {
+    constructor({ prop: [c] }) {
+    }
+}
+// Object with multiple nested levels
+export class C6 {
+    constructor({ prop: { nested: [d] } }) {
+    }
+}
+// Multiple parameters with nested patterns
+export class C7 {
+    constructor([[e]], [{ f }]) {
+    }
+}
+// Nested pattern with rest element
+export class C8 {
+    constructor([[g, ...rest]]) {
+    }
+}
+// Complex nested pattern
+export class C9 {
+    constructor([[h, i], { j, k: [l] }]) {
+    }
+}
+
+
+//// [declarationEmitNestedBindingPattern.d.ts]
+export declare class C1 {
+    x: any;
+    constructor([[x]]: any[]);
+}
+export declare class C2 {
+    y: any;
+    constructor([{ y }]: any[]);
+}
+export declare class C3 {
+    z: any;
+    constructor([[[z]]]: any[]);
+}
+export declare class C4 {
+    b: any;
+    constructor([{ a: [b] }]: any[]);
+}
+export declare class C5 {
+    c: any;
+    constructor({ prop: [c] }: any);
+}
+export declare class C6 {
+    d: any;
+    constructor({ prop: { nested: [d] } }: any);
+}
+export declare class C7 {
+    e: any;
+    f: any;
+    constructor([[e]]: any[], [{ f }]: any[]);
+}
+export declare class C8 {
+    g: any;
+    rest: any;
+    constructor([[g, ...rest]]: any[]);
+}
+export declare class C9 {
+    h: any;
+    i: any;
+    j: any;
+    l: any;
+    constructor([[h, i], { j, k: [l] }]: any);
+}

tests/baselines/reference/declarationEmitNestedBindingPattern.symbols

@@ -0,0 +1,85 @@
+//// [tests/cases/compiler/declarationEmitNestedBindingPattern.ts] ////
+
+=== declarationEmitNestedBindingPattern.ts ===
+// Nested array binding pattern
+export class C1 {
+>C1 : Symbol(C1, Decl(declarationEmitNestedBindingPattern.ts, 0, 0))
+
+    constructor(public [[x]]: any[]) {}
+>x : Symbol(x, Decl(declarationEmitNestedBindingPattern.ts, 2, 25))
+}
+
+// Nested object binding pattern
+export class C2 {
+>C2 : Symbol(C2, Decl(declarationEmitNestedBindingPattern.ts, 3, 1))
+
+    constructor(public [{y}]: any[]) {}
+>y : Symbol(y, Decl(declarationEmitNestedBindingPattern.ts, 7, 25))
+}
+
+// Multiple levels of array nesting
+export class C3 {
+>C3 : Symbol(C3, Decl(declarationEmitNestedBindingPattern.ts, 8, 1))
+
+    constructor(public [[[z]]]: any[]) {}
+>z : Symbol(z, Decl(declarationEmitNestedBindingPattern.ts, 12, 26))
+}
+
+// Mixed array and object nesting
+export class C4 {
+>C4 : Symbol(C4, Decl(declarationEmitNestedBindingPattern.ts, 13, 1))
+
+    constructor(public [{a: [b]}]: any[]) {}
+>b : Symbol(b, Decl(declarationEmitNestedBindingPattern.ts, 17, 29))
+}
+
+// Object with nested array
+export class C5 {
+>C5 : Symbol(C5, Decl(declarationEmitNestedBindingPattern.ts, 18, 1))
+
+    constructor(public {prop: [c]}: any) {}
+>c : Symbol(c, Decl(declarationEmitNestedBindingPattern.ts, 22, 31))
+}
+
+// Object with multiple nested levels
+export class C6 {
+>C6 : Symbol(C6, Decl(declarationEmitNestedBindingPattern.ts, 23, 1))
+
+    constructor(public {prop: {nested: [d]}}: any) {}
+>d : Symbol(d, Decl(declarationEmitNestedBindingPattern.ts, 27, 40))
+}
+
+// Multiple parameters with nested patterns
+export class C7 {
+>C7 : Symbol(C7, Decl(declarationEmitNestedBindingPattern.ts, 28, 1))
+
+    constructor(
+        public [[e]]: any[],
+>e : Symbol(e, Decl(declarationEmitNestedBindingPattern.ts, 33, 17))
+
+        public [{f}]: any[]
+>f : Symbol(f, Decl(declarationEmitNestedBindingPattern.ts, 34, 17))
+
+    ) {}
+}
+
+// Nested pattern with rest element
+export class C8 {
+>C8 : Symbol(C8, Decl(declarationEmitNestedBindingPattern.ts, 36, 1))
+
+    constructor(public [[g, ...rest]]: any[]) {}
+>g : Symbol(g, Decl(declarationEmitNestedBindingPattern.ts, 40, 25))
+>rest : Symbol(rest, Decl(declarationEmitNestedBindingPattern.ts, 40, 27))
+}
+
+// Complex nested pattern
+export class C9 {
+>C9 : Symbol(C9, Decl(declarationEmitNestedBindingPattern.ts, 41, 1))
+
+    constructor(public [[h, i], {j, k: [l]}]: any) {}
+>h : Symbol(h, Decl(declarationEmitNestedBindingPattern.ts, 45, 25))
+>i : Symbol(i, Decl(declarationEmitNestedBindingPattern.ts, 45, 27))
+>j : Symbol(j, Decl(declarationEmitNestedBindingPattern.ts, 45, 33))
+>l : Symbol(l, Decl(declarationEmitNestedBindingPattern.ts, 45, 40))
+}
+

tests/baselines/reference/declarationEmitNestedBindingPattern.types

@@ -0,0 +1,118 @@
+//// [tests/cases/compiler/declarationEmitNestedBindingPattern.ts] ////
+
+=== declarationEmitNestedBindingPattern.ts ===
+// Nested array binding pattern
+export class C1 {
+>C1 : C1
+>   : ^^
+
+    constructor(public [[x]]: any[]) {}
+>x : any
+>  : ^^^
+}
+
+// Nested object binding pattern
+export class C2 {
+>C2 : C2
+>   : ^^
+
+    constructor(public [{y}]: any[]) {}
+>y : any
+>  : ^^^
+}
+
+// Multiple levels of array nesting
+export class C3 {
+>C3 : C3
+>   : ^^
+
+    constructor(public [[[z]]]: any[]) {}
+>z : any
+>  : ^^^
+}
+
+// Mixed array and object nesting
+export class C4 {
+>C4 : C4
+>   : ^^
+
+    constructor(public [{a: [b]}]: any[]) {}
+>a : any
+>  : ^^^
+>b : any
+>  : ^^^
+}
+
+// Object with nested array
+export class C5 {
+>C5 : C5
+>   : ^^
+
+    constructor(public {prop: [c]}: any) {}
+>prop : any
+>     : ^^^
+>c : any
+>  : ^^^
+}
+
+// Object with multiple nested levels
+export class C6 {
+>C6 : C6
+>   : ^^
+
+    constructor(public {prop: {nested: [d]}}: any) {}
+>prop : any
+>     : ^^^
+>nested : any
+>       : ^^^
+>d : any
+>  : ^^^
+}
+
+// Multiple parameters with nested patterns
+export class C7 {
+>C7 : C7
+>   : ^^
+
+    constructor(
+        public [[e]]: any[],
+>e : any
+>  : ^^^
+
+        public [{f}]: any[]
+>f : any
+>  : ^^^
+
+    ) {}
+}
+
+// Nested pattern with rest element
+export class C8 {
+>C8 : C8
+>   : ^^
+
+    constructor(public [[g, ...rest]]: any[]) {}
+>g : any
+>  : ^^^
+>rest : any
+>     : ^^^
+}
+
+// Complex nested pattern
+export class C9 {
+>C9 : C9
+>   : ^^
+
+    constructor(public [[h, i], {j, k: [l]}]: any) {}
+>h : any
+>  : ^^^
+>i : any
+>  : ^^^
+>j : any
+>  : ^^^
+>k : any
+>  : ^^^
+>l : any
+>  : ^^^
+}
+

tests/cases/compiler/declarationEmitNestedBindingPattern.ts

@@ -0,0 +1,49 @@
+// @declaration: true
+
+// Nested array binding pattern
+export class C1 {
+    constructor(public [[x]]: any[]) {}
+}
+
+// Nested object binding pattern
+export class C2 {
+    constructor(public [{y}]: any[]) {}
+}
+
+// Multiple levels of array nesting
+export class C3 {
+    constructor(public [[[z]]]: any[]) {}
+}
+
+// Mixed array and object nesting
+export class C4 {
+    constructor(public [{a: [b]}]: any[]) {}
+}
+
+// Object with nested array
+export class C5 {
+    constructor(public {prop: [c]}: any) {}
+}
+
+// Object with multiple nested levels
+export class C6 {
+    constructor(public {prop: {nested: [d]}}: any) {}
+}
+
+// Multiple parameters with nested patterns
+export class C7 {
+    constructor(
+        public [[e]]: any[],
+        public [{f}]: any[]
+    ) {}
+}
+
+// Nested pattern with rest element
+export class C8 {
+    constructor(public [[g, ...rest]]: any[]) {}
+}
+
+// Complex nested pattern
+export class C9 {
+    constructor(public [[h, i], {j, k: [l]}]: any) {}
+}