feat(semantic): report no class name error (#2273)

closes #2144

crates/oxc_semantic/src/checker/javascript.rs

@@ -77,7 +77,7 @@ impl EarlyErrorJavaScript {
                 }
             }
 
-            AstKind::Class(class) => check_class(class, ctx),
+            AstKind::Class(class) => check_class(class, node, ctx),
             AstKind::Super(sup) => check_super(sup, node, ctx),
             AstKind::ObjectProperty(prop) => check_object_property(prop, ctx),
 
@@ -743,7 +743,7 @@ fn check_for_statement_left<'a>(
     }
 }
 
-fn check_class(class: &Class, ctx: &SemanticBuilder<'_>) {
+fn check_class(class: &Class, node: &AstNode<'_>, ctx: &SemanticBuilder<'_>) {
     #[derive(Debug, Error, Diagnostic)]
     #[error("Multiple constructor implementations are not allowed.")]
     #[diagnostic()]
@@ -752,8 +752,24 @@ fn check_class(class: &Class, ctx: &SemanticBuilder<'_>) {
         #[label("it cannot be redeclared here")] Span,
     );
 
+    #[derive(Debug, Error, Diagnostic)]
+    #[error("A class name is required.")]
+    #[diagnostic()]
+    struct RequireClassName(#[label] Span);
+
     check_private_identifier(ctx);
 
+    if class.is_declaration()
+        && class.id.is_none()
+        && !matches!(
+            ctx.nodes.parent_kind(node.id()),
+            Some(AstKind::ModuleDeclaration(ModuleDeclaration::ExportDefaultDeclaration(_)))
+        )
+    {
+        let start = class.span.start;
+        ctx.error(RequireClassName(Span::new(start, start + 5)));
+    }
+
     // ClassBody : ClassElementList
     // It is a Syntax Error if PrototypePropertyNameList of ClassElementList contains more than one occurrence of "constructor".
     let mut prev_constructor: Option<Span> = None;

tasks/coverage/misc/fail/oxc-2144.js

@@ -0,0 +1,2 @@
+class {}
+export class {}

tasks/coverage/parser_misc.snap

@@ -1,7 +1,7 @@
 parser_misc Summary:
 AST Parsed     : 10/10 (100.00%)
 Positive Passed: 10/10 (100.00%)
-Negative Passed: 6/6 (100.00%)
+Negative Passed: 7/7 (100.00%)
 
   × Unexpected token
    ╭─[fail/oxc-169.js:1:1]
@@ -24,6 +24,20 @@ Negative Passed: 6/6 (100.00%)
  3 │ }
    ╰────
 
+  × A class name is required.
+   ╭─[fail/oxc-2144.js:1:1]
+ 1 │ class {}
+   · ─────
+ 2 │ export class {}
+   ╰────
+
+  × A class name is required.
+   ╭─[fail/oxc-2144.js:2:8]
+ 1 │ class {}
+ 2 │ export class {}
+   ·        ─────
+   ╰────
+
   × Unexpected `?` operator
    ╭─[fail/oxc-2253.ts:1:8]
  1 │ const a? = "A"

tasks/coverage/parser_typescript.snap

@@ -1,7 +1,7 @@
 parser_typescript Summary:
 AST Parsed     : 5239/5243 (99.92%)
 Positive Passed: 5232/5243 (99.79%)
-Negative Passed: 1035/4879 (21.21%)
+Negative Passed: 1036/4879 (21.23%)
 Expect Syntax Error: "compiler/ClassDeclaration10.ts"
 Expect Syntax Error: "compiler/ClassDeclaration11.ts"
 Expect Syntax Error: "compiler/ClassDeclaration13.ts"
@@ -664,7 +664,6 @@ Expect Syntax Error: "compiler/expandoFunctionContextualTypesNoValue.ts"
 Expect Syntax Error: "compiler/exportAlreadySeen.ts"
 Expect Syntax Error: "compiler/exportAsNamespaceConflict.ts"
 Expect Syntax Error: "compiler/exportAssignmentWithExports.ts"
-Expect Syntax Error: "compiler/exportClassWithoutName.ts"
 Expect Syntax Error: "compiler/exportDeclarationsInAmbientNamespaces2.ts"
 Expect Syntax Error: "compiler/exportDeclareClass1.ts"
 Expect Syntax Error: "compiler/exportDefaultAlias_excludesEverything.ts"
@@ -6326,6 +6325,14 @@ Expect to Parse: "conformance/salsa/plainJSRedeclare3.ts"
    ·        ──────
    ╰────
 
+  × A class name is required.
+   ╭─[compiler/exportClassWithoutName.ts:3:8]
+ 2 │ //@target: es2015
+ 3 │ export class {
+   ·        ─────
+ 4 │ }
+   ╰────
+
   × Unexpected token
     ╭─[compiler/exportDeclarationInInternalModule.ts:17:19]
  16 │