Parse function typedef declarations at the function cursor

bindgen-tests/tests/headers/function-typedef-method.hpp

@@ -0,0 +1,21 @@
+// bindgen-flags: -- -std=c++17
+
+typedef int Function(int);
+using FunctionAlias = Function;
+
+struct First {
+    Function method;
+    static Function static_method;
+    int value;
+};
+
+struct Second {
+    FunctionAlias method;
+    int value;
+};
+
+struct Virtual {
+    virtual Function method;
+};
+
+Function free_function;

bindgen-tests/tests/tests.rs

@@ -803,6 +803,28 @@ fn commandline_multiple_headers() {
     build_flags_output_helper(&bindings);
 }
 
+#[test]
+fn test_wrap_static_function_typedef() {
+    let directory = tempfile::tempdir().unwrap();
+    let header = directory.path().join("function-typedef.h");
+    fs::write(
+        &header,
+        "typedef int Function(int);\nstatic Function take;\nstatic int take(int value) { return value + 10; }\n",
+    )
+    .unwrap();
+    let wrapper = directory.path().join("wrapper.c");
+    Builder::default()
+        .header(header.to_str().unwrap())
+        .wrap_static_fns(true)
+        .wrap_static_fns_path(&wrapper)
+        .generate()
+        .expect(
+            "Function typedefs must be resolved before serializing a wrapper",
+        );
+    let wrapper = fs::read_to_string(wrapper).unwrap();
+    assert!(wrapper.contains("return take("));
+}
+
 #[test]
 fn test_wrap_static_fns() {
     // This test is for testing diffs of the generated C source and header files

bindgen/ir/function.rs

@@ -771,7 +771,13 @@ impl ClangSubItemParser for Function {
         }
 
         // Grab the signature using Item::from_ty.
-        let sig = Item::from_ty(&cursor.cur_type(), cursor, None, context)?;
+        let mut ty = cursor.cur_type();
+        // Parse the signature at the function cursor so that methods declared
+        // through a function typedef still get their implicit receiver.
+        if matches!(ty.kind(), CXType_Typedef | CXType_Elaborated) {
+            ty = ty.canonical_type();
+        }
+        let sig = Item::from_ty(&ty, cursor, None, context)?;
 
         let mut name = cursor.spelling();
         assert!(!name.is_empty(), "Empty function name?");