fix(parser): should parser error when function declaration has no name

crates/oxc_parser/src/js/function.rs

@@ -11,7 +11,7 @@ use super::{list::FormalParameterList, FunctionKind};
 
 impl FunctionKind {
     pub(crate) fn is_id_required(self) -> bool {
-        matches!(self, Self::Declaration { single_statement: true })
+        matches!(self, Self::Declaration)
     }
 
     pub(crate) fn is_expression(self) -> bool {
@@ -80,7 +80,7 @@ impl<'a> ParserImpl<'a> {
         }
 
         let function_type = match func_kind {
-            FunctionKind::Declaration { .. } | FunctionKind::DefaultExport => {
+            FunctionKind::Declaration | FunctionKind::DefaultExport => {
                 if body.is_none() {
                     FunctionType::TSDeclareFunction
                 } else {
@@ -123,8 +123,7 @@ impl<'a> ParserImpl<'a> {
         &mut self,
         stmt_ctx: StatementContext,
     ) -> Result<Statement<'a>> {
-        let func_kind =
-            FunctionKind::Declaration { single_statement: stmt_ctx.is_single_statement() };
+        let func_kind = FunctionKind::Declaration;
         let decl = self.parse_function_impl(func_kind)?;
         if stmt_ctx.is_single_statement() {
             if decl.r#async {
@@ -153,7 +152,7 @@ impl<'a> ParserImpl<'a> {
         let r#async = self.eat(Kind::Async);
         self.expect(Kind::Function)?;
         let generator = self.eat(Kind::Star);
-        let id = self.parse_function_id(func_kind, r#async, generator);
+        let id = self.parse_function_id(func_kind, r#async, generator)?;
         self.parse_function(span, id, r#async, generator, func_kind, Modifiers::empty())
     }
 
@@ -168,7 +167,7 @@ impl<'a> ParserImpl<'a> {
         let r#async = modifiers.contains(ModifierKind::Async);
         self.expect(Kind::Function)?;
         let generator = self.eat(Kind::Star);
-        let id = self.parse_function_id(func_kind, r#async, generator);
+        let id = self.parse_function_id(func_kind, r#async, generator)?;
         self.parse_function(start_span, id, r#async, generator, func_kind, modifiers)
     }
 
@@ -182,7 +181,7 @@ impl<'a> ParserImpl<'a> {
         self.expect(Kind::Function)?;
 
         let generator = self.eat(Kind::Star);
-        let id = self.parse_function_id(func_kind, r#async, generator);
+        let id = self.parse_function_id(func_kind, r#async, generator)?;
         let function =
             self.parse_function(span, id, r#async, generator, func_kind, Modifiers::empty())?;
 
@@ -257,7 +256,7 @@ impl<'a> ParserImpl<'a> {
         kind: FunctionKind,
         r#async: bool,
         generator: bool,
-    ) -> Option<BindingIdentifier<'a>> {
+    ) -> Result<Option<BindingIdentifier<'a>>> {
         let ctx = self.ctx;
         if kind.is_expression() {
             self.ctx = self.ctx.and_await(r#async).and_yield(generator);
@@ -270,9 +269,15 @@ impl<'a> ParserImpl<'a> {
         self.ctx = ctx;
 
         if kind.is_id_required() && id.is_none() {
-            self.error(diagnostics::expect_function_name(self.cur_token().span()));
+            match self.cur_kind() {
+                Kind::LParen => {
+                    self.error(diagnostics::expect_function_name(self.cur_token().span()));
+                }
+                kind if kind.is_reserved_keyword() => self.expect_without_advance(Kind::Ident)?,
+                _ => {}
+            }
         }
 
-        id
+        Ok(id)
     }
 }

crates/oxc_parser/src/js/mod.rs

@@ -25,7 +25,7 @@ pub enum Tristate {
 
 #[derive(Debug, Clone, Copy, Eq, PartialEq)]
 pub enum FunctionKind {
-    Declaration { single_statement: bool },
+    Declaration,
     Expression,
     DefaultExport,
     TSDeclaration,

crates/oxc_parser/src/ts/statement.rs

@@ -325,14 +325,10 @@ impl<'a> ParserImpl<'a> {
                     self.parse_ts_declare_function(start_span, modifiers)
                         .map(Declaration::FunctionDeclaration)
                 } else if self.ts_enabled() {
-                    self.parse_ts_function_impl(
-                        start_span,
-                        FunctionKind::Declaration { single_statement: true },
-                        modifiers,
-                    )
-                    .map(Declaration::FunctionDeclaration)
+                    self.parse_ts_function_impl(start_span, FunctionKind::Declaration, modifiers)
+                        .map(Declaration::FunctionDeclaration)
                 } else {
-                    self.parse_function_impl(FunctionKind::Declaration { single_statement: true })
+                    self.parse_function_impl(FunctionKind::Declaration)
                         .map(Declaration::FunctionDeclaration)
                 }
             }
@@ -348,7 +344,7 @@ impl<'a> ParserImpl<'a> {
         let r#async = modifiers.contains(ModifierKind::Async);
         self.expect(Kind::Function)?;
         let func_kind = FunctionKind::TSDeclaration;
-        let id = self.parse_function_id(func_kind, r#async, false);
+        let id = self.parse_function_id(func_kind, r#async, false)?;
         self.parse_function(start_span, id, r#async, false, func_kind, modifiers)
     }
 

tasks/coverage/parser_babel.snap

@@ -1383,32 +1383,32 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
    ·            ────
    ╰────
 
-  × Expected `(` but found `null`
+  × Expected `Identifier` but found `null`
    ╭─[core/uncategorised/401/input.js:1:10]
  1 │ function null() { }
    ·          ──┬─
-   ·            ╰── `(` expected
+   ·            ╰── `Identifier` expected
    ╰────
 
-  × Expected `(` but found `true`
+  × Expected `Identifier` but found `true`
    ╭─[core/uncategorised/402/input.js:1:10]
  1 │ function true() { }
    ·          ──┬─
-   ·            ╰── `(` expected
+   ·            ╰── `Identifier` expected
    ╰────
 
-  × Expected `(` but found `false`
+  × Expected `Identifier` but found `false`
    ╭─[core/uncategorised/403/input.js:1:10]
  1 │ function false() { }
    ·          ──┬──
-   ·            ╰── `(` expected
+   ·            ╰── `Identifier` expected
    ╰────
 
-  × Expected `(` but found `if`
+  × Expected `Identifier` but found `if`
    ╭─[core/uncategorised/404/input.js:1:10]
  1 │ function if() { }
    ·          ─┬
-   ·           ╰── `(` expected
+   ·           ╰── `Identifier` expected
    ╰────
 
   × Expected a semicolon or an implicit semicolon after a statement, but found none
@@ -3667,11 +3667,11 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
    ╰────
   help: Try insert a semicolon here
 
-  × Expected `(` but found `default`
+  × Expected `Identifier` but found `default`
    ╭─[es2015/uncategorised/226/input.js:1:10]
  1 │ function default() {}
    ·          ───┬───
-   ·             ╰── `(` expected
+   ·             ╰── `Identifier` expected
    ╰────
 
   × Cannot assign to 'eval' in strict mode
@@ -4238,18 +4238,18 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
    ·                     ╰── `:` expected
    ╰────
 
-  × Expected `(` but found `enum`
+  × Expected `Identifier` but found `enum`
    ╭─[es2015/uncategorised/376/input.js:1:10]
  1 │ function enum() {}
    ·          ──┬─
-   ·            ╰── `(` expected
+   ·            ╰── `Identifier` expected
    ╰────
 
-  × Expected `(` but found `enum`
+  × Expected `Identifier` but found `enum`
    ╭─[es2015/uncategorised/377/input.js:1:10]
  1 │ function enum() {}
    ·          ──┬─
-   ·            ╰── `(` expected
+   ·            ╰── `Identifier` expected
    ╰────
 
   × Expected `{` but found `enum`
@@ -5010,6 +5010,13 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
    · ──────────
    ╰────
 
+  × Expected function name
+   ╭─[es2017/async-functions/invalid-escape-sequence-function/input.js:1:20]
+ 1 │ \u0061sync function() { await x }
+   ·                    ─
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × Keywords cannot contain escape characters
    ╭─[es2017/async-functions/invalid-escape-sequence-function-list/input.js:1:2]
  1 │ (\u0061sync function() { await x })
@@ -7126,6 +7133,15 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
    ·      ─────
    ╰────
 
+  × Expected function name
+   ╭─[esprima/es2015-generator/generator-parameter-binding-element/input.js:2:13]
+ 1 │ (function*() {
+ 2 │     function(x = yield 3) {}
+   ·             ─
+ 3 │ })
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × A 'yield' expression is only allowed in a generator body.
    ╭─[esprima/es2015-generator/generator-parameter-binding-element/input.js:2:18]
  1 │ (function*() {
@@ -7143,6 +7159,15 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
  3 │ })
    ╰────
 
+  × Expected function name
+   ╭─[esprima/es2015-generator/generator-parameter-binding-property/input.js:2:13]
+ 1 │ (function*() {
+ 2 │     function({x: y = yield 3}) {}
+   ·             ─
+ 3 │ })
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × A 'yield' expression is only allowed in a generator body.
    ╭─[esprima/es2015-generator/generator-parameter-binding-property/input.js:2:22]
  1 │ (function*() {
@@ -7160,6 +7185,15 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
  3 │ })
    ╰────
 
+  × Expected function name
+   ╭─[esprima/es2015-generator/generator-parameter-computed-property-name/input.js:2:13]
+ 1 │ (function*() {
+ 2 │     function({[yield 3]: y}) {}
+   ·             ─
+ 3 │ })
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × A 'yield' expression is only allowed in a generator body.
    ╭─[esprima/es2015-generator/generator-parameter-computed-property-name/input.js:2:16]
  1 │ (function*() {
@@ -7177,6 +7211,15 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
  3 │ })
    ╰────
 
+  × Expected function name
+   ╭─[esprima/es2015-generator/generator-parameter-invalid-binding-element/input.js:2:14]
+ 1 │ (function*() {
+ 2 │     function*(x = yield 3) {}
+   ·              ─
+ 3 │ })
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × yield expression not allowed in formal parameter
    ╭─[esprima/es2015-generator/generator-parameter-invalid-binding-element/input.js:2:19]
  1 │ (function*() {
@@ -7186,6 +7229,15 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
  3 │ })
    ╰────
 
+  × Expected function name
+   ╭─[esprima/es2015-generator/generator-parameter-invalid-binding-property/input.js:2:14]
+ 1 │ (function*() {
+ 2 │     function*({x: y = yield 3}) {}
+   ·              ─
+ 3 │ })
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × yield expression not allowed in formal parameter
    ╭─[esprima/es2015-generator/generator-parameter-invalid-binding-property/input.js:2:23]
  1 │ (function*() {
@@ -7195,6 +7247,15 @@ Expect to Parse: "typescript/types/const-type-parameters-babel-7/input.ts"
  3 │ })
    ╰────
 
+  × Expected function name
+   ╭─[esprima/es2015-generator/generator-parameter-invalid-computed-property-name/input.js:2:14]
+ 1 │ (function*() {
+ 2 │     function*({[yield 3]: y}) {}
+   ·              ─
+ 3 │ })
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × yield expression not allowed in formal parameter
    ╭─[esprima/es2015-generator/generator-parameter-invalid-computed-property-name/input.js:2:17]
  1 │ (function*() {

tasks/coverage/parser_test262.snap

@@ -3587,13 +3587,29 @@ Expect Syntax Error: "language/import/import-attributes/json-named-bindings.js"
     · ───
     ╰────
 
+  × Expected function name
+    ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-asyncfunctionexpression.js:16:16]
+ 15 │ 
+ 16 │ async function () {} = 1;
+    ·                ─
+    ╰────
+  help: Function name is required in function declaration or named export
+
   × Unexpected token
     ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-asyncfunctionexpression.js:16:22]
  15 │ 
  16 │ async function () {} = 1;
     ·                      ─
     ╰────
 
+  × Expected function name
+    ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-asyncgeneratorexpression.js:16:16]
+ 15 │ 
+ 16 │ async function () {} = 1;
+    ·                ─
+    ╰────
+  help: Function name is required in function declaration or named export
+
   × Unexpected token
     ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-asyncgeneratorexpression.js:16:22]
  15 │ 
@@ -3608,13 +3624,29 @@ Expect Syntax Error: "language/import/import-attributes/json-named-bindings.js"
     ·          ─
     ╰────
 
+  × Expected function name
+    ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-functionexpression.js:16:9]
+ 15 │ 
+ 16 │ function() {} = 1;
+    ·         ─
+    ╰────
+  help: Function name is required in function declaration or named export
+
   × Unexpected token
     ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-functionexpression.js:16:15]
  15 │ 
  16 │ function() {} = 1;
     ·               ─
     ╰────
 
+  × Expected function name
+    ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-generatorexpression.js:16:12]
+ 15 │ 
+ 16 │ function * () {} = 1;
+    ·            ─
+    ╰────
+  help: Function name is required in function declaration or named export
+
   × Unexpected token
     ╭─[language/expressions/assignmenttargettype/direct-primaryexpression-generatorexpression.js:16:18]
  15 │ 
@@ -28778,6 +28810,15 @@ Expect Syntax Error: "language/import/import-attributes/json-named-bindings.js"
     ╰────
   help: Wrap this declaration in a block statement
 
+  × Expected function name
+    ╭─[language/statements/expression/S12.4_A1.js:19:9]
+ 18 │ //CHECK#1
+ 19 │ function(){}();
+    ·         ─
+ 20 │ //
+    ╰────
+  help: Function name is required in function declaration or named export
+
   × Empty parenthesized expression
     ╭─[language/statements/expression/S12.4_A1.js:19:13]
  18 │ //CHECK#1

tasks/coverage/parser_typescript.snap

@@ -16857,6 +16857,13 @@ Expect to Parse: "conformance/salsa/plainJSRedeclare3.ts"
    ·           ╰── `(` expected
    ╰────
 
+  × Expected function name
+   ╭─[conformance/parser/ecmascript5/ErrorRecovery/parserEqualsGreaterThanAfterFunction2.ts:1:10]
+ 1 │ function (a => b;
+   ·          ─
+   ╰────
+  help: Function name is required in function declaration or named export
+
   × Expected `,` but found `=>`
    ╭─[conformance/parser/ecmascript5/ErrorRecovery/parserEqualsGreaterThanAfterFunction2.ts:1:13]
  1 │ function (a => b;