[typer] deal with AKResolve for assign-ops

closes #9758

src/typing/operators.ml

@@ -629,11 +629,14 @@ let type_non_assign_op ctx op e1 e2 is_assign_op abstract_overload_only with_typ
 	vr#to_texpr e
 
 let type_assign_op ctx op e1 e2 with_type p =
-	let field_rhs op cf ev =
-		let access_get = type_field_default_cfg ctx ev cf.cf_name p MGet (WithType.with_type cf.cf_type) in
+	let field_rhs_by_name op name ev with_type =
+		let access_get = type_field_default_cfg ctx ev name p MGet with_type in
 		let e_get = acc_get ctx access_get p in
 		e_get.etype,type_binop2 ctx op e_get e2 true (WithType.with_type e_get.etype) p
 	in
+	let field_rhs op cf ev =
+		field_rhs_by_name op cf.cf_name ev (WithType.with_type cf.cf_type)
+	in
 	let process_lhs name e_lhs =
 		let vr = new value_reference ctx in
 		let e = vr#get_expr name e_lhs in
@@ -724,8 +727,15 @@ let type_assign_op ctx op e1 e2 with_type p =
 		in
 		save();
 		vr#to_texpr	e
-	| AKResolve _ ->
-		error "Invalid operation" p
+	| AKResolve(sea,name) ->
+		let e,vr = process_lhs "fh" sea.se_this in
+		let t_lhs,r_rhs = field_rhs_by_name op name e WithType.value in
+		let assign e_rhs =
+			let e_name = Texpr.Builder.make_string ctx.t name null_pos in
+			(new call_dispatcher ctx (MCall [e2]) with_type p)#field_call sea.se_access [sea.se_this;e_name;e_rhs] []
+		in
+		let e = BinopResult.to_texpr vr r_rhs assign in
+		vr#to_texpr e
 	)
 
 let type_binop ctx op e1 e2 is_assign_op with_type p =

tests/unit/src/unit/issues/Issue9758.hx

@@ -0,0 +1,55 @@
+package unit.issues;
+
+private abstract Resolver(String) {
+	public function new(value:String) {
+		this = value;
+	}
+
+	@:op(a.b) function resolveRead(name:String) {
+		return new Resolver('$this.$name');
+	}
+
+	@:op(a.b) function resolveWrite(name:String, value:Resolver) {
+		return new Resolver('$this.$name = $value');
+	}
+
+	@:op(a * b) function mul(rhs:Resolver) {
+		return new Resolver('$this * ${rhs.getString()}');
+	}
+
+	@:op(a -= b) function subAssign(rhs:Resolver) {
+		return new Resolver('$this -= ${rhs.getString()}');
+	}
+
+	public function getString() {
+		return this;
+	}
+
+	@:from static function fromString(s:String) {
+		return new Resolver(s);
+	}
+}
+
+class Issue9758 extends unit.Test {
+	function test() {
+		var resolver = new Resolver("resolver");
+		resolver = resolver.readme;
+		eq("resolver.readme", resolver.getString());
+
+		var resolver = new Resolver("resolver");
+		resolver = resolver.writeMe = "writeMeValue";
+		eq("resolver.writeMe = writeMeValue", resolver.getString());
+
+		var resolver = new Resolver("resolver");
+		resolver = (resolver.readAndWriteMe = resolver.readAndWriteMe * "readAndWriteMeValue");
+		eq("resolver.readAndWriteMe = resolver.readAndWriteMe * readAndWriteMeValue", resolver.getString());
+
+		var resolver = new Resolver("resolver");
+		resolver = (resolver.readAndWriteMe *= "readAndWriteMeValue");
+		eq("resolver.readAndWriteMe = resolver.readAndWriteMe * readAndWriteMeValue", resolver.getString());
+
+		var resolver = new Resolver("resolver");
+		resolver = (resolver.readAndWriteMe -= "readAndWriteMeValue");
+		eq("resolver.readAndWriteMe -= readAndWriteMeValue", resolver.getString());
+	}
+}