fix(parser): parse empty method declaration as TSEmptyBodyFunctionExp…

…ression (#2574)

That a tricky one, because it's time to decide what does ESTree
compliant means in the TS world (re #2463)

This code:

```ts
export declare class ByteBuffer {
  clear(): void;
     // ^^
}
```

- Is parsed by
[Babel](https://astexplorer.net/#/gist/9f43cf0fe91760e11f1572934681c92f/d38530204eaa6e12dbd14f3ef2d7d2fcb7da7bc2)
as `FunctionExpression` with an empty body
- By
[TS-ESLint](https://astexplorer.net/#/gist/626dd346956a02c221d4e128450652af/4ea4e2feb5ae7bb8787f8c7e452d442c935c1f09)
as
[TSEmptyBodyFunctionExpression](typescript-eslint/typescript-eslint#1289)
- By
[OXC](https://oxc-project.github.io/oxc/playground/?code=3YCAAIC1gICAgICAgICyHorESipoTXPdvBaE9wxzlOraoWs19SUxDvdcwSVU0kbBO2b7ppX3x2P5IhQlpGHOYEHNCEfLf38HUICA)
as `TSDeclareFunction`

I'm going the easy way to fix this to the Babel way, but I think
following TS-ESLint would make sense. There is an [open babel
issue](babel/babel#13878) about that.

Edit: Ok that not so easy and require updating some logic.

---------

Co-authored-by: Boshen <[email protected]>

crates/oxc_ast/src/ast/js.rs

@@ -1770,6 +1770,8 @@ pub enum FunctionType {
     FunctionDeclaration,
     FunctionExpression,
     TSDeclareFunction,
+    /// <https://github.com/typescript-eslint/typescript-eslint/pull/1289>
+    TSEmptyBodyFunctionExpression,
 }
 
 /// <https://tc39.es/ecma262/#prod-FormalParameters>

crates/oxc_parser/src/js/function.rs

@@ -105,16 +105,22 @@ impl<'a> ParserImpl<'a> {
             return Err(self.unexpected());
         }
 
-        let function_type = if body.is_none() {
-            FunctionType::TSDeclareFunction
-        } else {
-            match func_kind {
-                FunctionKind::Declaration { .. } | FunctionKind::DefaultExport => {
+        let function_type = match func_kind {
+            FunctionKind::Declaration { .. } | FunctionKind::DefaultExport => {
+                if body.is_none() {
+                    FunctionType::TSDeclareFunction
+                } else {
                     FunctionType::FunctionDeclaration
                 }
-                FunctionKind::Expression { .. } => FunctionType::FunctionExpression,
-                FunctionKind::TSDeclaration { .. } => FunctionType::TSDeclareFunction,
             }
+            FunctionKind::Expression { .. } => {
+                if body.is_none() {
+                    FunctionType::TSEmptyBodyFunctionExpression
+                } else {
+                    FunctionType::FunctionExpression
+                }
+            }
+            FunctionKind::TSDeclaration { .. } => FunctionType::TSDeclareFunction,
         };
 
         if FunctionType::TSDeclareFunction == function_type {

tasks/coverage/parser_typescript.snap

@@ -1326,7 +1326,6 @@ Expect Syntax Error: "compiler/objectLiteralFreshnessWithSpread.ts"
 Expect Syntax Error: "compiler/objectLiteralFunctionArgContextualTyping.ts"
 Expect Syntax Error: "compiler/objectLiteralFunctionArgContextualTyping2.ts"
 Expect Syntax Error: "compiler/objectLiteralIndexerErrors.ts"
-Expect Syntax Error: "compiler/objectLiteralMemberWithoutBlock1.ts"
 Expect Syntax Error: "compiler/objectLiteralParameterResolution.ts"
 Expect Syntax Error: "compiler/objectLiteralPropertyImplicitlyAny.ts"
 Expect Syntax Error: "compiler/objectLiteralReferencingInternalProperties.ts"
@@ -3550,6 +3549,7 @@ Expect Syntax Error: "conformance/types/nonPrimitive/nonPrimitiveUnionIntersecti
 Expect Syntax Error: "conformance/types/objectTypeLiteral/callSignatures/callSignatureWithOptionalParameterAndInitializer.ts"
 Expect Syntax Error: "conformance/types/objectTypeLiteral/callSignatures/callSignaturesThatDifferOnlyByReturnType2.ts"
 Expect Syntax Error: "conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers.ts"
+Expect Syntax Error: "conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts"
 Expect Syntax Error: "conformance/types/objectTypeLiteral/callSignatures/specializedSignatureIsNotSubtypeOfNonSpecializedSignature.ts"
 Expect Syntax Error: "conformance/types/objectTypeLiteral/callSignatures/stringLiteralTypesInImplementationSignatures2.ts"
 Expect Syntax Error: "conformance/types/objectTypeLiteral/callSignatures/typeParameterUsedAsTypeParameterConstraint4.ts"
@@ -7941,6 +7941,13 @@ Expect to Parse: "conformance/salsa/plainJSRedeclare3.ts"
    ·              ╰── `,` expected
    ╰────
 
+  × Expected `,` but found `;`
+   ╭─[compiler/objectLiteralMemberWithoutBlock1.ts:1:16]
+ 1 │ var v = { foo(); }
+   ·                ┬
+   ·                ╰── `,` expected
+   ╰────
+
   × Expected `,` but found `;`
    ╭─[compiler/objectLiteralWithSemicolons1.ts:1:12]
  1 │ var v = { a; b; c }
@@ -19577,15 +19584,6 @@ Expect to Parse: "conformance/salsa/plainJSRedeclare3.ts"
  38 │ }
     ╰────
 
-  × Expected a semicolon or an implicit semicolon after a statement, but found none
-    ╭─[conformance/types/objectTypeLiteral/callSignatures/callSignaturesWithParameterInitializers2.ts:20:15]
- 19 │ var b = {
- 20 │     foo(x = 1), // error
-    ·               ▲
- 21 │     foo(x = 1) { }, // error
-    ╰────
-  help: Try insert a semicolon here
-
   × A parameter property is only allowed in a constructor implementation.
     ╭─[conformance/types/objectTypeLiteral/callSignatures/constructSignatureWithAccessibilityModifiersOnParameters.ts:16:10]
  15 │ interface I {