From 73e28ec523163f2335a32583a07ec421d97e7f9b Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Thu, 6 Oct 2022 22:25:02 +0800
Subject: [PATCH] checker: fix infering fn type using reference argument
 (#15978)

---
 vlib/v/checker/check_types.v                   | 18 ++++++++++++++++++
 ...neric_fn_infer_fn_type_using_ref_arg_test.v | 12 ++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 vlib/v/tests/generic_fn_infer_fn_type_using_ref_arg_test.v

diff --git a/vlib/v/checker/check_types.v b/vlib/v/checker/check_types.v
index bc28a80d6e..b828c56b90 100644
--- a/vlib/v/checker/check_types.v
+++ b/vlib/v/checker/check_types.v
@@ -714,6 +714,9 @@ pub fn (mut c Checker) infer_fn_generic_types(func ast.Fn, mut node ast.CallExpr
 						} else {
 							if param_elem_sym.name == gt_name {
 								typ = arg_elem_info.elem_type
+								if param_elem_info.elem_type.nr_muls() > 0 && typ.nr_muls() > 0 {
+									typ = typ.set_nr_muls(0)
+								}
 							}
 							break
 						}
@@ -734,6 +737,9 @@ pub fn (mut c Checker) infer_fn_generic_types(func ast.Fn, mut node ast.CallExpr
 						} else {
 							if param_elem_sym.name == gt_name {
 								typ = arg_elem_info.elem_type
+								if param_elem_info.elem_type.nr_muls() > 0 && typ.nr_muls() > 0 {
+									typ = typ.set_nr_muls(0)
+								}
 							}
 							break
 						}
@@ -744,10 +750,16 @@ pub fn (mut c Checker) infer_fn_generic_types(func ast.Fn, mut node ast.CallExpr
 					if param_map_info.key_type.has_flag(.generic)
 						&& c.table.sym(param_map_info.key_type).name == gt_name {
 						typ = arg_map_info.key_type
+						if param_map_info.key_type.nr_muls() > 0 && typ.nr_muls() > 0 {
+							typ = typ.set_nr_muls(0)
+						}
 					}
 					if param_map_info.value_type.has_flag(.generic)
 						&& c.table.sym(param_map_info.value_type).name == gt_name {
 						typ = arg_map_info.value_type
+						if param_map_info.value_type.nr_muls() > 0 && typ.nr_muls() > 0 {
+							typ = typ.set_nr_muls(0)
+						}
 					}
 				} else if arg_sym.kind == .function && param_type_sym.kind == .function {
 					arg_type_func := (arg_sym.info as ast.FnType).func
@@ -757,11 +769,17 @@ pub fn (mut c Checker) infer_fn_generic_types(func ast.Fn, mut node ast.CallExpr
 							if fn_param.typ.has_flag(.generic)
 								&& c.table.sym(fn_param.typ).name == gt_name {
 								typ = arg_type_func.params[n].typ
+								if fn_param.typ.nr_muls() > 0 && typ.nr_muls() > 0 {
+									typ = typ.set_nr_muls(0)
+								}
 							}
 						}
 						if param_type_func.return_type.has_flag(.generic)
 							&& c.table.sym(param_type_func.return_type).name == gt_name {
 							typ = arg_type_func.return_type
+							if param_type_func.return_type.nr_muls() > 0 && typ.nr_muls() > 0 {
+								typ = typ.set_nr_muls(0)
+							}
 						}
 					}
 				} else if arg_sym.kind in [.struct_, .interface_, .sum_type] {
diff --git a/vlib/v/tests/generic_fn_infer_fn_type_using_ref_arg_test.v b/vlib/v/tests/generic_fn_infer_fn_type_using_ref_arg_test.v
new file mode 100644
index 0000000000..a809d45b00
--- /dev/null
+++ b/vlib/v/tests/generic_fn_infer_fn_type_using_ref_arg_test.v
@@ -0,0 +1,12 @@
+fn test_generic_fn_infer_fn_type_using_ref_arg() {
+	ret := call_generic_fn(fn (a &int) bool {
+		return *a > 0
+	}, 1)
+	assert ret
+}
+
+fn call_generic_fn<T>(cb fn (&T) bool, input T) bool {
+	dump(cb(&input))
+	ret := cb(&input)
+	return ret
+}