Unified: Handle Swift's macro expansion expr

paldepind · Oct 2, 2026 · Oct 2, 2026 · Oct 2, 2026 · Oct 2, 2026 · 78320a0a66872d917b025c916f570fdf642b21fe
commit 78320a0a66872d917b025c916f570fdf642b21fe
@@ -712,6 +712,31 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
             =>
             (argument name_node: (identifier #{lbl})? value: {val})
         ),
+        // An additional labeled trailing closure, such as the `c: { ... }` in
+        // `foo { 42 } c: { ... }`, is turned into an argument to the function.
+        rule!(
+            (multipleTrailingClosureElement label: @@label closure: @closure)
+            =>
+            (argument name_node: (identifier #{label}) value: {closure})
+        ),
+        rule!(
+            (macroExpansionExpr
+                macroName: @@name
+                genericArgumentClause: (genericArgumentClause arguments: (genericArgument argument: @type_args)*)?
+                arguments: _* @args
+                trailingClosure: _? @trailing
+                additionalTrailingClosures: _* @additional)
+            =>
+            macro_call_expr {
+                let mut arguments = args;
+                arguments.extend(trailing.into_iter().map(|trailing| tree!((argument value: {trailing}))));
+                arguments.extend(additional);
+                tree!((macro_call_expr
+                    macro_name_node: (identifier #{name})
+                    type_argument: {type_args}
+                    argument: {arguments}))
+            }
+        ),
         // Member access (`list.append`). The `declName` is itself a
         // `declReferenceExpr`; pull its `baseName` out as the member identifier.
         // A leading-dot access (`.foo`) has no explicit base — the base is an
@@ -1196,10 +1221,6 @@ fn translation_rules() -> Vec<Rule<SwiftContext>> {
                 }
             }
         ),
-        // Selector expression: `#selector(inner)` -- not yet supported
-        // (swift-syntax represents `#selector`/`#keyPath` and other macro
-        // expansions uniformly as a `macroExpansionExpr`).
-        rule!((macroExpansionExpr) => (unsupported_node)),
         // A nominal type's `inheritanceClause` (`: Base, Proto`) becomes a list
         // of `base_type`s, one per inherited type. Each declaration keyword
         // gets its own rule; the bodies are identical but for the keyword.

@@ -120,6 +120,45 @@ top_level source="⟨body⟩"
   body:
     block source="⟨stmt⟩\n\n⟨stmt⟩\n\n⟨stmt⟩"
       stmt:
-        unsupported_node "#expect(value == 42)" source="#expect(value == 42)"
-        unsupported_node "#custom<Int>(value) {\n  value\n} completion: {\n  value\n}" source="#custom<Int>(value) {\n  value\n} completion: {\n  value\n}"
-        unsupported_node "#Preview {\n  let previewValue = 42\n  previewValue\n}" source="#Preview {\n  let previewValue = 42\n  previewValue\n}"
+        macro_call_expr source="#⟨macro_name_node⟩(⟨argument⟩)"
+          macro_name_node: identifier "expect" source="expect"
+          argument:
+            argument source="⟨value⟩"
+              value:
+                binary_expr source="⟨left⟩ ⟨operator⟩ ⟨right⟩"
+                  left: identifier "value" source="value"
+                  operator: infix_operator "==" source="=="
+                  right: int_literal "42" source="42"
+        macro_call_expr source="#⟨macro_name_node⟩<⟨type_argument⟩>(⟨argument⟩) ⟨argument⟩ ⟨argument⟩"
+          macro_name_node: identifier "custom" source="custom"
+          type_argument: identifier "Int" source="Int"
+          argument:
+            argument source="⟨value⟩"
+              value: identifier "value" source="value"
+            argument source="⟨value⟩"
+              value:
+                function_expr source="{\n  ⟨body⟩\n}"
+                  body:
+                    block source="⟨stmt⟩"
+                      stmt: identifier "value" source="value"
+            argument source="⟨name_node⟩: ⟨value⟩"
+              name_node: identifier "completion" source="completion"
+              value:
+                function_expr source="{\n  ⟨body⟩\n}"
+                  body:
+                    block source="⟨stmt⟩"
+                      stmt: identifier "value" source="value"
+        macro_call_expr source="#⟨macro_name_node⟩ ⟨argument⟩"
+          macro_name_node: identifier "Preview" source="Preview"
+          argument:
+            argument source="⟨value⟩"
+              value:
+                function_expr source="{\n  ⟨body⟩\n}"
+                  body:
+                    block source="⟨stmt⟩\n  ⟨stmt⟩"
+                      stmt:
+                        variable_declaration source="⟨modifier⟩ ⟨pattern⟩ = ⟨value⟩"
+                          modifier: modifier "let" source="let"
+                          pattern: identifier "previewValue" source="previewValue"
+                          value: int_literal "42" source="42"
+                        identifier "previewValue" source="previewValue"
@@ -35,4 +35,6 @@ top_level source="⟨body⟩"
         variable_declaration source="⟨modifier⟩ ⟨pattern⟩ = ⟨value⟩"
           modifier: modifier "let" source="let"
           pattern: identifier "currentLine" source="currentLine"
-          value: unsupported_node "#line" source="#line"
+          value:
+            macro_call_expr source="#⟨macro_name_node⟩"
+              macro_name_node: identifier "line" source="line"