GDScript: Allow using await on calls to void functions

modules/gdscript/gdscript_analyzer.cpp

@@ -2467,7 +2467,7 @@ void GDScriptAnalyzer::reduce_call(GDScriptParser::CallNode *p_call, bool p_is_a
 		} else if (GDScriptUtilityFunctions::function_exists(function_name)) {
 			MethodInfo function_info = GDScriptUtilityFunctions::get_function_info(function_name);
 
-			if (!p_is_root && function_info.return_val.type == Variant::NIL && ((function_info.return_val.usage & PROPERTY_USAGE_NIL_IS_VARIANT) == 0)) {
+			if (!p_is_root && !p_is_await && function_info.return_val.type == Variant::NIL && ((function_info.return_val.usage & PROPERTY_USAGE_NIL_IS_VARIANT) == 0)) {
 				push_error(vformat(R"*(Cannot get return value of call to "%s()" because it returns "void".)*", function_name), p_call);
 			}
 
@@ -2514,7 +2514,7 @@ void GDScriptAnalyzer::reduce_call(GDScriptParser::CallNode *p_call, bool p_is_a
 		} else if (Variant::has_utility_function(function_name)) {
 			MethodInfo function_info = info_from_utility_func(function_name);
 
-			if (!p_is_root && function_info.return_val.type == Variant::NIL && ((function_info.return_val.usage & PROPERTY_USAGE_NIL_IS_VARIANT) == 0)) {
+			if (!p_is_root && !p_is_await && function_info.return_val.type == Variant::NIL && ((function_info.return_val.usage & PROPERTY_USAGE_NIL_IS_VARIANT) == 0)) {
 				push_error(vformat(R"*(Cannot get return value of call to "%s()" because it returns "void".)*", function_name), p_call);
 			}
 
@@ -2660,7 +2660,7 @@ void GDScriptAnalyzer::reduce_call(GDScriptParser::CallNode *p_call, bool p_is_a
 			mark_lambda_use_self();
 		}
 
-		if (!p_is_root && return_type.is_hard_type() && return_type.kind == GDScriptParser::DataType::BUILTIN && return_type.builtin_type == Variant::NIL) {
+		if (!p_is_root && !p_is_await && return_type.is_hard_type() && return_type.kind == GDScriptParser::DataType::BUILTIN && return_type.builtin_type == Variant::NIL) {
 			push_error(vformat(R"*(Cannot get return value of call to "%s()" because it returns "void".)*", p_call->function_name), p_call);
 		}
 

modules/gdscript/tests/scripts/runtime/features/await_on_void.gd

@@ -0,0 +1,7 @@
+func wait() -> void:
+	pass
+
+func test():
+	@warning_ignore(redundant_await)
+	await wait()
+	print("end")

modules/gdscript/tests/scripts/runtime/features/await_on_void.out

@@ -0,0 +1,2 @@
+GDTEST_OK
+end