[cpp] Callable comparison handling

src/generators/cpp/gen/cppGen.ml

@@ -1610,6 +1610,9 @@ let gen_cpp_ast_expression_tree ctx class_name func_name function_args function_
     output_i "int __Compare(const ::hx::Object* inRhs) const override {\n";
     output_i (Printf.sprintf "\treturn dynamic_cast<const _hx_Closure_%i*>(inRhs) ? 0 : -1;\n" closure.close_id);
     output_i "}\n";
+    output_i "std::type_index callableId() const override {\n";
+    output_i (Printf.sprintf "\treturn std::type_index{ typeid(_hx_Closure_%i) };\n" closure.close_id);
+    output_i "}\n";
 
     let return =
       match closure.close_type with TCppVoid -> "(void)" | _ -> "return"

src/generators/genjvm.ml

@@ -1134,7 +1134,10 @@ class texpr_to_jvm
 		| [TObject(path1,_);sig2] when jc#has_typed_function path1 || path1 = haxe_function_path ->
 			code#swap;
 			fun_compare path1 sig2
-		| [(TObject _ | TArray _ | TMethod _) as t1;(TObject _ | TArray _ | TMethod _) as t2] ->
+		| [TMethod _;_] | [_;TMethod _] ->
+			jm#invokestatic haxe_jvm_path "compareFunctions" (method_sig [object_sig;object_sig] (Some TBool));
+			CmpNormal(op,TBool)
+		| [(TObject _ | TArray _) as t1;(TObject _ | TArray _) as t2] ->
 			CmpSpecial ((if op = CmpEq then code#if_acmp_ne else code#if_acmp_eq) t1 t2)
 		| [TDouble;TDouble] ->
 			let op = flip_cmp_op op in

std/jvm/Jvm.hx

@@ -71,6 +71,10 @@ class Jvm {
 		return Reflect.compare(v1, v2);
 	}
 
+	static public function compareFunctions(v1:Dynamic, v2:Dynamic):Bool {
+		return Reflect.compareMethods(v1, v2);
+	}
+
 	static public function enumEq(v1:Dynamic, v2:Dynamic) {
 		if (!instanceof(v1, jvm.Enum)) {
 			return false;

tests/unit/src/unit/issues/Issue12746.hx

@@ -0,0 +1,31 @@
+package unit.issues;
+
+private class Event {}
+private class MouseEvent extends Event {}
+private class Foo {
+	public function onMouseMove(e:MouseEvent):Void {}
+
+	public function new() {}
+}
+
+class Issue12746 extends Test {
+	function test() {
+#if !neko
+		final obj = new Foo();
+
+		final a:Event->Void = cast obj.onMouseMove;
+		final b:Event->Void = cast obj.onMouseMove;
+		t(a == b);
+
+		t(genericCast(obj.onMouseMove, obj.onMouseMove));
+#else
+		utest.Assert.pass(); // See PR 12763 discussion
+#end
+	}
+
+	static function genericCast<T:Event>(a:T->Void, b:T->Void):Bool {
+		var ca:Event->Void = cast a;
+		var cb:Event->Void = cast b;
+		return ca == cb;
+	}
+}