fix(isolated_declarations): Remove nested AssignmentPatterns from ins…

…ide parameters

crates/oxc_isolated_declarations/src/formal_parameter_binding_pattern.rs

@@ -0,0 +1,24 @@
+use oxc_ast::{
+    ast::BindingPatternKind, visit::walk_mut::walk_binding_pattern_kind, AstBuilder, VisitMut,
+};
+
+pub struct FormalParameterBindingPattern<'a> {
+    ast: AstBuilder<'a>,
+}
+
+impl<'a> VisitMut<'a> for FormalParameterBindingPattern<'a> {
+    fn visit_binding_pattern_kind(&mut self, kind: &mut BindingPatternKind<'a>) {
+        if let BindingPatternKind::AssignmentPattern(assignment) = kind {
+            *kind = self.ast.copy(&assignment.left.kind);
+        }
+
+        walk_binding_pattern_kind(self, kind);
+    }
+}
+
+impl<'a> FormalParameterBindingPattern<'a> {
+    pub fn remove_assignments_from_kind(ast: AstBuilder<'a>, kind: &mut BindingPatternKind<'a>) {
+        let mut visitor = FormalParameterBindingPattern { ast };
+        visitor.visit_binding_pattern_kind(kind);
+    }
+}

crates/oxc_isolated_declarations/src/function.rs

@@ -9,6 +9,7 @@ use crate::{
         function_must_have_explicit_return_type, implicitly_adding_undefined_to_type,
         parameter_must_have_explicit_type,
     },
+    formal_parameter_binding_pattern::FormalParameterBindingPattern,
     IsolatedDeclarations,
 };
 
@@ -65,6 +66,8 @@ impl<'a> IsolatedDeclarations<'a> {
                 self.ast.copy(&param.pattern)
             };
 
+        FormalParameterBindingPattern::remove_assignments_from_kind(self.ast, &mut pattern.kind);
+
         if is_assignment_pattern || pattern.type_annotation.is_none() {
             let type_annotation = pattern
                 .type_annotation

crates/oxc_isolated_declarations/src/lib.rs

@@ -9,6 +9,7 @@ mod class;
 mod declaration;
 mod diagnostics;
 mod r#enum;
+mod formal_parameter_binding_pattern;
 mod function;
 mod inferrer;
 mod literal;

crates/oxc_isolated_declarations/tests/fixtures/function-parameters.ts

@@ -10,6 +10,10 @@ export const fooGood2 = ({a, b}: object = { a: 1, b: 2 }): number => {
   return 2;
 }
 
+const x = 42;
+const y = '';
+export function fooGood3({a = x, b: [{c = y}]}: object): void {}
+
 // Incorrect
 export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
 export function fnDeclBad2<T>(p: T = [], r2: T): void { }

crates/oxc_isolated_declarations/tests/snapshots/function-parameters.snap

@@ -8,6 +8,7 @@ export declare function fnDeclGood(p?: T, rParam?: string): void;
 export declare function fnDeclGood2(p?: T, rParam?: number): void;
 export declare function fooGood([a, b]?: any[]): number;
 export declare const fooGood2: ({ a, b }?: object) => number;
+export declare function fooGood3({ a, b: [{ c }] }: object): void;
 export declare function fnDeclBad<T>(p: T, rParam: T, r2: T): void;
 export declare function fnDeclBad2<T>(p: T, r2: T): void;
 export declare function fnDeclBad3<T>(p: T, rParam?: T, r2: T): void;
@@ -19,54 +20,54 @@ export declare const fooBad2: () => number;
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[14:30]
- 13 | // Incorrect
- 14 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
+    ,-[18:30]
+ 17 | // Incorrect
+ 18 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
     :                              ^^^^^^^^^
- 15 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+ 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
     `----
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[14:41]
- 13 | // Incorrect
- 14 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
+    ,-[18:41]
+ 17 | // Incorrect
+ 18 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
     :                                         ^^^^^^^^^^^^^^
- 15 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+ 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
     `----
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[15:31]
- 14 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
- 15 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+    ,-[19:31]
+ 18 | export function fnDeclBad<T>(p: T = [], rParam: T = "", r2: T): void { }
+ 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
     :                               ^^^^^^^^^
- 16 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
+ 20 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
     `----
 
   x TS9025: Declaration emit for this parameter requires implicitly adding
   | undefined to it's type. This is not supported with --isolatedDeclarations.
-    ,-[16:31]
- 15 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
- 16 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
+    ,-[20:31]
+ 19 | export function fnDeclBad2<T>(p: T = [], r2: T): void { }
+ 20 | export function fnDeclBad3<T>(p: T = [], rParam?: T, r2: T): void { }
     :                               ^^^^^^^^^
- 17 | 
+ 21 | 
     `----
 
   x TS9011: Parameter must have an explicit type annotation with
   | --isolatedDeclarations.
-    ,-[18:24]
- 17 | 
- 18 | export function fooBad([a, b] = [1, 2]): number {
+    ,-[22:24]
+ 21 | 
+ 22 | export function fooBad([a, b] = [1, 2]): number {
     :                        ^^^^^^^^^^^^^^^
- 19 |   return 2;
+ 23 |   return 2;
     `----
 
   x TS9011: Parameter must have an explicit type annotation with
   | --isolatedDeclarations.
-    ,-[22:25]
- 21 | 
- 22 | export const fooBad2 = ({a, b} = { a: 1, b: 2 }): number => {
+    ,-[26:25]
+ 25 | 
+ 26 | export const fooBad2 = ({a, b} = { a: 1, b: 2 }): number => {
     :                         ^^^^^^^^^^^^^^^^^^^^^^^
- 23 |   return 2;
+ 27 |   return 2;
     `----