fix(parser): should parser error when function declaration has no name (#3461)

https://oxc-project.github.io/oxc/playground/?code=3YCAAICNgICAgICAgICzncl%2FKeF7k4Y7upgY2l43c79%2FYxaAgA%3D%3D

Author: Dunqing

crates/oxc_linter/src/rules/eslint/array_callback_return/return_checker.rs

@@ -279,7 +279,7 @@ mod tests {
     fn test_switch_always_explicit() {
         // Return Explicit
         let always_explicit = r#"
-    function() {
+    function d() {
       switch (a) {
         case "C":
           switch (b) {
@@ -299,7 +299,7 @@ mod tests {
     #[test]
     fn test_switch_always_implicit() {
         let always_implicit = r#"
-    function() {
+    function d() {
       switch (a) {
         case "C":
           switch (b) {
@@ -319,7 +319,7 @@ mod tests {
     #[test]
     fn test_switch_always_mixed() {
         let always_mixed = r#"
-        function() {
+        function d() {
           switch (a) {
             case "C":
               switch (b) {

crates/oxc_linter/src/rules/eslint/no_obj_calls.rs

@@ -199,7 +199,7 @@ fn test() {
         ("let obj = Intl();", None),
         ("let newObj = new Reflect();", None),
         ("let obj = Reflect();", None),
-        ("function() { JSON.parse(Atomics()) }", None),
+        ("function d() { JSON.parse(Atomics()) }", None),
         // reference test cases
         ("let j = JSON; j();", None),
         ("let a = JSON; let b = a; let c = b; b();", None),

crates/oxc_linter/src/rules/jsdoc/require_yields.rs

@@ -102,13 +102,13 @@ impl Rule for RequireYields {
         // This rule checks generator function should have JSDoc `@yields` tag.
         // By default, this rule only checks:
         // ```
-        // function*() { yield withValue; }
+        // function*d() { yield withValue; }
         // ```
         //
         // If `config.forceRequireYields` is `true`, also checks:
         // ```
-        // function*() {}
-        // function*() { yield; }
+        // function*d() {}
+        // function*d() { yield; }
         // ```
         //
         // If generator function does not have JSDoc, it will be skipped.
@@ -673,7 +673,7 @@ fn test() {
         			           * @generator
         			           * @yields
         			           */
-                        function*() {yield 1;}
+                        function*d() {yield 1;}
         			      ",
             Some(serde_json::json!([
               {
@@ -853,7 +853,7 @@ fn test() {
       			           * @function
       			           * @generator
       			           */
-                        function*() {}
+                        function*d() {}
       			      ",
             Some(serde_json::json!([
               {
@@ -1446,7 +1446,7 @@ fn test() {
         			           * fail(`@generator`+missing `@yields`, with config)
         			           * @generator
         			           */
-                        function*() {}
+                        function*d() {}
         			      ",
             Some(serde_json::json!([{ "withGeneratorTag": true, }])),
             None,

crates/oxc_linter/src/snapshots/no_obj_calls.snap

@@ -108,9 +108,9 @@ expression: no_obj_calls
   help: Reflect is not a function.
 
   ⚠ eslint(no-obj-calls): Disallow calling some global objects as functions
-   ╭─[no_obj_calls.tsx:1:25]
- 1 │ function() { JSON.parse(Atomics()) }
-   ·                         ─────────
+   ╭─[no_obj_calls.tsx:1:27]
+ 1 │ function d() { JSON.parse(Atomics()) }
+   ·                           ─────────
    ╰────
   help: Atomics is not a function.
 

crates/oxc_linter/src/snapshots/require_yields.snap

@@ -97,8 +97,8 @@ expression: require_yields
   ⚠ eslint-plugin-jsdoc(require-yields): Missing JSDoc `@yields` declaration for generator function.
    ╭─[require_yields.tsx:6:25]
  5 │                            */
- 6 │                         function*() {}
-   ·                         ──────────────
+ 6 │                         function*d() {}
+   ·                         ───────────────
  7 │                       
    ╰────
   help: Add `@yields` tag to the JSDoc comment.

crates/oxc_module_lexer/tests/esm.rs

@@ -728,7 +728,7 @@ import { g } from './test-circular2.js';
 
 #[test]
 fn comments() {
-    let source = " /*\n                   VERSION\n                 */\nimport util from 'util';\n\n//\nfunction x() {\n}\n\n/**/\n// '\n/* / */\n/*\n\n   * export { b }\n\\*/\nexport { a }\n\n      function () {\n/***/\n      }\n    ";
+    let source = " /*\n                   VERSION\n                 */\nimport util from 'util';\n\n//\nfunction x() {\n}\n\n/**/\n// '\n/* / */\n/*\n\n   * export { b }\n\\*/\nexport { a }\n\n      function d() {\n/***/\n      }\n    ";
     let ModuleLexer { imports, exports, .. } = parse(source);
     assert_eq!(imports.len(), 1);
     assert_eq!(source.slice(imports[0].s, imports[0].e), "util");

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)
     }