feat(semantic): check redeclaration of function declaration and class declaration (#10093)

Preparing for #10094. This will lead to a duplicate error of redeclaration of function and class, but it will be removed in #10094.

Author: Dunqing

crates/oxc_semantic/src/checker/javascript.rs

@@ -492,6 +492,21 @@ pub fn check_function_redeclaration(func: &Function, ctx: &SemanticBuilder<'_>)
     ctx.error(redeclaration(&id.name, prev.span, id.span));
 }
 
+pub fn check_class_redeclaration(class: &Class, ctx: &SemanticBuilder<'_>) {
+    let Some(id) = &class.id else { return };
+    let symbol_id = id.symbol_id();
+
+    let redeclarations = ctx.scoping.symbol_redeclarations(symbol_id);
+    let Some(prev) = redeclarations.iter().nth_back(1) else {
+        // No redeclarations
+        return;
+    };
+
+    if prev.flags.contains(SymbolFlags::Function) {
+        ctx.error(redeclaration(&id.name, prev.span, id.span));
+    }
+}
+
 fn reg_exp_flag_u_and_v(span: Span) -> OxcDiagnostic {
     OxcDiagnostic::error(
         "The 'u' and 'v' regular expression flags cannot be enabled at the same time",

crates/oxc_semantic/src/checker/mod.rs

@@ -76,6 +76,9 @@ pub fn check<'a>(node: &AstNode<'a>, ctx: &SemanticBuilder<'a>) {
         }
         AstKind::Class(class) => {
             js::check_class(class, node, ctx);
+            if !is_typescript {
+                js::check_class_redeclaration(class, ctx);
+            }
             ts::check_class(class, ctx);
         }
         AstKind::Function(func) if !is_typescript => {

tasks/coverage/snapshots/parser_test262.snap

@@ -2691,6 +2691,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/block-scope/syntax/redeclaration/async-function-name-redeclaration-attempt-with-class.js:24:18]
  23 │ 
+ 24 │ { async function f() {} class f {} }
+    ·                  ┬            ┬
+    ·                  │            ╰── It can not be redeclared here
+    ·                  ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/block-scope/syntax/redeclaration/async-function-name-redeclaration-attempt-with-class.js:24:18]
+ 23 │ 
  24 │ { async function f() {} class f {} }
     ·                  ┬            ┬
     ·                  │            ╰── It can not be redeclared here
@@ -2763,6 +2772,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/block-scope/syntax/redeclaration/async-generator-name-redeclaration-attempt-with-class.js:24:19]
  23 │ 
+ 24 │ { async function* f() {} class f {} }
+    ·                   ┬            ┬
+    ·                   │            ╰── It can not be redeclared here
+    ·                   ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/block-scope/syntax/redeclaration/async-generator-name-redeclaration-attempt-with-class.js:24:19]
+ 23 │ 
  24 │ { async function* f() {} class f {} }
     ·                   ┬            ┬
     ·                   │            ╰── It can not be redeclared here
@@ -3064,6 +3082,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/block-scope/syntax/redeclaration/function-name-redeclaration-attempt-with-class.js:23:12]
  22 │ 
+ 23 │ { function f() {} class f {} }
+    ·            ┬            ┬
+    ·            │            ╰── It can not be redeclared here
+    ·            ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/block-scope/syntax/redeclaration/function-name-redeclaration-attempt-with-class.js:23:12]
+ 22 │ 
  23 │ { function f() {} class f {} }
     ·            ┬            ┬
     ·            │            ╰── It can not be redeclared here
@@ -3136,6 +3163,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/block-scope/syntax/redeclaration/generator-name-redeclaration-attempt-with-class.js:24:13]
  23 │ 
+ 24 │ { function* f() {} class f {} }
+    ·             ┬            ┬
+    ·             │            ╰── It can not be redeclared here
+    ·             ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/block-scope/syntax/redeclaration/generator-name-redeclaration-attempt-with-class.js:24:13]
+ 23 │ 
  24 │ { function* f() {} class f {} }
     ·             ┬            ┬
     ·             │            ╰── It can not be redeclared here
@@ -38252,6 +38288,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/statements/switch/syntax/redeclaration/async-function-name-redeclaration-attempt-with-class.js:24:37]
  23 │ 
+ 24 │ switch (0) { case 1: async function f() {} default: class f {} }
+    ·                                     ┬                     ┬
+    ·                                     │                     ╰── It can not be redeclared here
+    ·                                     ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/statements/switch/syntax/redeclaration/async-function-name-redeclaration-attempt-with-class.js:24:37]
+ 23 │ 
  24 │ switch (0) { case 1: async function f() {} default: class f {} }
     ·                                     ┬                     ┬
     ·                                     │                     ╰── It can not be redeclared here
@@ -38324,6 +38369,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/statements/switch/syntax/redeclaration/async-generator-name-redeclaration-attempt-with-class.js:24:38]
  23 │ 
+ 24 │ switch (0) { case 1: async function* f() {} default: class f {} }
+    ·                                      ┬                     ┬
+    ·                                      │                     ╰── It can not be redeclared here
+    ·                                      ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/statements/switch/syntax/redeclaration/async-generator-name-redeclaration-attempt-with-class.js:24:38]
+ 23 │ 
  24 │ switch (0) { case 1: async function* f() {} default: class f {} }
     ·                                      ┬                     ┬
     ·                                      │                     ╰── It can not be redeclared here
@@ -38540,6 +38594,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/statements/switch/syntax/redeclaration/function-name-redeclaration-attempt-with-class.js:23:31]
  22 │ 
+ 23 │ switch (0) { case 1: function f() {} default: class f {} }
+    ·                               ┬                     ┬
+    ·                               │                     ╰── It can not be redeclared here
+    ·                               ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/statements/switch/syntax/redeclaration/function-name-redeclaration-attempt-with-class.js:23:31]
+ 22 │ 
  23 │ switch (0) { case 1: function f() {} default: class f {} }
     ·                               ┬                     ┬
     ·                               │                     ╰── It can not be redeclared here
@@ -38612,6 +38675,15 @@ Expect to Parse: tasks/coverage/test262/test/language/statements/function/S14_A5
   × Identifier `f` has already been declared
     ╭─[test262/test/language/statements/switch/syntax/redeclaration/generator-name-redeclaration-attempt-with-class.js:24:32]
  23 │ 
+ 24 │ switch (0) { case 1: function* f() {} default: class f {} }
+    ·                                ┬                     ┬
+    ·                                │                     ╰── It can not be redeclared here
+    ·                                ╰── `f` has already been declared here
+    ╰────
+
+  × Identifier `f` has already been declared
+    ╭─[test262/test/language/statements/switch/syntax/redeclaration/generator-name-redeclaration-attempt-with-class.js:24:32]
+ 23 │ 
  24 │ switch (0) { case 1: function* f() {} default: class f {} }
     ·                                ┬                     ┬
     ·                                │                     ╰── It can not be redeclared here