feat(semantic): check for non-declared, non-abstract class accessors without bodies (#5460)

This should be causing more negative tests to fail than it actually is. This is
because our typescript coverage tests use the "declarations" option to change
the source type to `.d.ts`, which is incorrect. This setting enables `.d.ts`
emits, it does not mean that input files should be treated as `.d.ts`
themselves.

crates/oxc_ast/src/ast_impl/js.rs

@@ -1423,6 +1423,11 @@ impl MethodDefinitionKind {
         matches!(self, Self::Get)
     }
 
+    /// Returns `true` if this method is a getter or a setter.
+    pub fn is_accessor(&self) -> bool {
+        matches!(self, Self::Get | Self::Set)
+    }
+
     pub fn scope_flags(self) -> ScopeFlags {
         match self {
             Self::Constructor => ScopeFlags::Constructor | ScopeFlags::Function,

crates/oxc_semantic/src/checker/typescript.rs

@@ -287,8 +287,29 @@ fn parameter_property_only_in_constructor_impl(span: Span) -> OxcDiagnostic {
         .with_label(span)
 }
 
+/// Getter or setter without a body. There is no corresponding TS error code,
+/// since in TSC this is a parse error.
+fn accessor_without_body(span: Span) -> OxcDiagnostic {
+    OxcDiagnostic::error("Getters and setters must have an implementation.").with_label(span)
+}
+
 pub fn check_method_definition<'a>(method: &MethodDefinition<'a>, ctx: &SemanticBuilder<'a>) {
-    if method.r#type.is_abstract() {
+    let is_abstract = method.r#type.is_abstract();
+    let is_declare = ctx.class_table_builder.current_class_id.map_or(
+        ctx.source_type.is_typescript_definition(),
+        |id| {
+            let ast_node_id = ctx.class_table_builder.classes.declarations[id];
+            let AstKind::Class(class) = ctx.nodes.get_node(ast_node_id).kind() else {
+                #[cfg(debug_assertions)]
+                panic!("current_class_id is set, but does not point to a Class node.");
+                #[cfg(not(debug_assertions))]
+                return ctx.source_type.is_typescript_definition();
+            };
+            class.declare || ctx.source_type.is_typescript_definition()
+        },
+    );
+
+    if is_abstract {
         // constructors cannot be abstract, no matter what
         if method.kind.is_constructor() {
             ctx.error(illegal_abstract_modifier(method.key.span()));
@@ -313,16 +334,20 @@ pub fn check_method_definition<'a>(method: &MethodDefinition<'a>, ctx: &Semantic
         }
     }
 
+    let is_empty_body = method.value.r#type == FunctionType::TSEmptyBodyFunctionExpression;
     // Illegal to have `constructor(public foo);`
-    if method.kind.is_constructor()
-        && method.value.r#type == FunctionType::TSEmptyBodyFunctionExpression
-    {
+    if method.kind.is_constructor() && is_empty_body {
         for param in &method.value.params.items {
             if param.accessibility.is_some() {
                 ctx.error(parameter_property_only_in_constructor_impl(param.span));
             }
         }
     }
+
+    // Illegal to have `get foo();` or `set foo(a)`
+    if method.kind.is_accessor() && is_empty_body && !is_abstract && !is_declare {
+        ctx.error(accessor_without_body(method.key.span()));
+    }
 }
 
 pub fn check_property_definition<'a>(prop: &PropertyDefinition<'a>, ctx: &SemanticBuilder<'a>) {

tasks/coverage/parser_babel.snap

@@ -3,7 +3,7 @@ commit: 3bcfee23
 parser_babel Summary:
 AST Parsed     : 2093/2101 (99.62%)
 Positive Passed: 2083/2101 (99.14%)
-Negative Passed: 1381/1493 (92.50%)
+Negative Passed: 1382/1493 (92.57%)
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/annex-b/enabled/3.1-sloppy-labeled-functions-if-body/input.js
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-labeled-inside-if/input.js
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/core/categorized/invalid-fn-decl-labeled-inside-loop/input.js
@@ -39,7 +39,6 @@ Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/ty
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/constructor-with-invalid-order-modifiers-3/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/constructor-with-type-parameters/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/constructor-with-type-parameters-babel-7/input.ts
-Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/declare-accessor/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/declare-field-initializer/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/declare-initializer/input.ts
 Expect Syntax Error: tasks/coverage/babel/packages/babel-parser/test/fixtures/typescript/class/declare-method/input.ts
@@ -10039,6 +10038,22 @@ Expect to Parse: tasks/coverage/babel/packages/babel-parser/test/fixtures/typesc
  8 │   abstract accessor f = 1;
    ╰────
 
+  × Getters and setters must have an implementation.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/declare-accessor/input.ts:2:15]
+ 1 │ class Foo {
+ 2 │   declare get foo()
+   ·               ───
+ 3 │   declare set foo(v)
+   ╰────
+
+  × Getters and setters must have an implementation.
+   ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/declare-accessor/input.ts:3:15]
+ 2 │   declare get foo()
+ 3 │   declare set foo(v)
+   ·               ───
+ 4 │ }
+   ╰────
+
   × Expected a semicolon or an implicit semicolon after a statement, but found none
    ╭─[babel/packages/babel-parser/test/fixtures/typescript/class/declare-new-line-abstract/input.ts:1:8]
  1 │ declare abstract

tasks/coverage/parser_typescript.snap

@@ -5021,6 +5021,14 @@ Expect to Parse: tasks/coverage/typescript/tests/cases/conformance/salsa/typeFro
    ╰────
   help: Try insert a semicolon here
 
+  × Getters and setters must have an implementation.
+    ╭─[typescript/tests/cases/compiler/abstractPropertyNegative.ts:16:9]
+ 15 │     abstract notAllowed: string;
+ 16 │     get concreteWithNoBody(): string;
+    ·         ──────────────────
+ 17 │ }
+    ╰────
+
   × TS(1253): Abstract properties can only appear within an abstract class.
     ╭─[typescript/tests/cases/compiler/abstractPropertyNegative.ts:15:14]
  14 │     readonly ro = "readonly please";