[typer] Monomorph vs Null<T> inference

src/typing/typer.ml

@@ -401,7 +401,7 @@ let rec type_ident_raise ctx i p mode with_type =
 					| TMono r when not (is_nullable t) ->
 						(* If our expected type is a monomorph, bind it to Null<?>. The is_nullable check is here because
 							the expected type could already be Null<?>, in which case we don't want to double-wrap (issue #11286). *)
-						Monomorph.do_bind r (tnull())
+						Monomorph.bind r (tnull())
 					| _ ->
 						(* Otherwise there's no need to create a monomorph, we can just type the null literal
 						the way we expect it. *)

tests/misc/projects/Issue11753/Main.hx

@@ -0,0 +1,31 @@
+class Main {
+	static var doThings : Foo -> Void;
+
+	static function main() {
+		var foo = new Foo();
+		doThings = (foo -> doThingsImpl(foo));
+		doThings(foo);
+	}
+
+	static function doThingsImpl(foo) {
+		foo.doWithBar();
+		$type(foo);
+		$type(foo.doWithBar);
+
+		if (foo != null) trace(foo);
+		$type(foo);
+		$type(foo.doWithBar);
+	}
+}
+
+class Foo {
+	public function new() {}
+	public function doWithBar(?bar:Bar) {
+		trace(bar);
+	}
+}
+
+@:keep
+class Bar {
+	public function new() {}
+}

tests/misc/projects/Issue11753/compile-fail.hxml

@@ -0,0 +1,4 @@
+-main Main
+--hl bin/main.hl
+-D message.reporting=pretty
+-D message.no-color

tests/misc/projects/Issue11753/compile-fail.hxml.stderr

@@ -0,0 +1,32 @@
+[WARNING] Main.hx:12: characters 9-12
+
+ 12 |   $type(foo);
+    |         ^^^
+    | Unknown<0> : { doWithBar : () -> Unknown<1> }
+
+[WARNING] Main.hx:13: characters 9-22
+
+ 13 |   $type(foo.doWithBar);
+    |         ^^^^^^^^^^^^^
+    | () -> Unknown<0>
+
+[WARNING] Main.hx:16: characters 9-12
+
+ 16 |   $type(foo);
+    |         ^^^
+    | Null<{ doWithBar : () -> Unknown<0> }>
+
+[WARNING] Main.hx:17: characters 9-22
+
+ 17 |   $type(foo.doWithBar);
+    |         ^^^^^^^^^^^^^
+    | () -> Unknown<0>
+
+[ERROR] Main.hx:6: characters 35-38
+
+  6 |   doThings = (foo -> doThingsImpl(foo));
+    |                                   ^^^
+    | error: (?bar : Null<Bar>) -> Void should be () -> Unknown<0>
+    | have: { doWithBar: (?...) -> ... }
+    | want: { doWithBar: () -> ... }
+