fix(parser): allow non-last rest element in ambient contexts

crates/oxc_parser/src/diagnostics.rs

@@ -130,7 +130,7 @@ pub struct ClassDeclaration(#[label] pub Span);
 #[derive(Debug, Error, Diagnostic)]
 #[error("Rest element must be last element")]
 #[diagnostic()]
-pub struct RestElement(#[label] pub Span);
+pub struct RestElementLast(#[label] pub Span);
 
 #[derive(Debug, Error, Diagnostic)]
 #[error("Spread must be last element")]

crates/oxc_parser/src/js/binding.rs

@@ -56,8 +56,8 @@ impl<'a> Parser<'a> {
         if self.at(Kind::Comma) {
             if self.peek_at(Kind::RBrack) {
                 self.error(diagnostics::RestElementTrailingComma(self.cur_token().span()));
-            } else {
-                self.error(diagnostics::RestElement(span));
+            } else if !self.ctx.has_ambient() {
+                self.error(diagnostics::RestElementLast(span));
             }
         }
 

tasks/coverage/babel.snap

@@ -1,6 +1,6 @@
 Babel Summary:
 AST Parsed     : 2065/2071 (99.71%)
-Positive Passed: 2057/2071 (99.32%)
+Positive Passed: 2058/2071 (99.37%)
 Negative Passed: 1332/1502 (88.68%)
 Expect Syntax Error: "annex-b/disabled/1.1-html-comments-close/input.js"
 Expect Syntax Error: "annex-b/disabled/3.1-sloppy-labeled-functions-if-body/input.js"
@@ -240,13 +240,6 @@ Expect to Parse: "typescript/class/constructor-with-modifier-names/input.ts"
    ·        ╰── it cannot be redeclared here
  4 │ }
    ╰────
-Expect to Parse: "typescript/declare/function-rest-trailing-comma/input.ts"
-
-  × Rest element must be last element
-   ╭─[typescript/declare/function-rest-trailing-comma/input.ts:1:1]
- 1 │ declare function foo(...args: any[], )
-   ·                      ──────────────
-   ╰────
 Expect to Parse: "typescript/dts/no-initializer/input.ts"
 
   × Missing initializer in const declaration

tasks/coverage/typescript.snap

@@ -7241,14 +7241,6 @@ Expect to Parse: "salsa/privateIdentifierExpando.ts"
  8 │ 
    ╰────
 
-  × Rest element must be last element
-    ╭─[es7/trailingCommasInFunctionParametersAndArguments.ts:9:1]
-  9 │ // Allowed for ambient declarations
- 10 │ declare function f25(...args,): void;
-    ·                      ───────
- 11 │ 
-    ╰────
-
   × Unexpected token
    ╭─[es7/trailingCommasInGetter.ts:1:1]
  1 │ class X {