From 41dca3ef580a7849724564cd62019bcf3e77cf14 Mon Sep 17 00:00:00 2001
From: joe-conigliaro <joe.conigliaro@gmail.com>
Date: Thu, 4 Jun 2020 19:32:31 +1000
Subject: [PATCH] checker/cgen: fix mutable generic fn args

---
 vlib/v/checker/checker.v     |  2 +-
 vlib/v/gen/fn.v              |  7 ++++---
 vlib/v/parser/fn.v           | 12 ++++++++----
 vlib/v/tests/generics_test.v |  2 +-
 4 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 3500747b8f..b7a64f4086 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -1749,7 +1749,7 @@ fn (mut c Checker) stmts(stmts []ast.Stmt) {
 }
 
 pub fn (mut c Checker) unwrap_generic(typ table.Type) table.Type {
-	if typ == table.t_type {
+	if typ.idx() == table.t_type_idx {
 		return c.cur_generic_type
 	}
 	return typ
diff --git a/vlib/v/gen/fn.v b/vlib/v/gen/fn.v
index 0c89ff56b0..5e894c475b 100644
--- a/vlib/v/gen/fn.v
+++ b/vlib/v/gen/fn.v
@@ -315,8 +315,9 @@ fn (mut g Gen) fn_args(args []table.Arg, is_variadic bool) ([]string, []string)
 	no_names := args.len > 0 && args[0].name == 'arg_1'
 	for i, arg in args {
 		caname := c_name(arg.name)
-		arg_type_sym := g.table.get_type_symbol(arg.typ)
-		mut arg_type_name := g.typ(arg.typ) // arg_type_sym.name.replace('.', '__')
+		typ := g.unwrap_generic(arg.typ).set_nr_muls(arg.typ.nr_muls())
+		arg_type_sym := g.table.get_type_symbol(typ)
+		mut arg_type_name := g.typ(typ) // arg_type_sym.name.replace('.', '__')
 		// if arg.name == 'xxx' {
 		// println('! ' + arg_type_name)
 		// }
@@ -400,7 +401,7 @@ fn (mut g Gen) call_expr(node ast.CallExpr) {
 }
 
 pub fn (mut g Gen) unwrap_generic(typ table.Type) table.Type {
-	if typ == table.t_type {
+	if typ.idx() == table.t_type_idx {
 		return g.cur_generic_type
 	}
 	return typ
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index ccd0b3eacc..23e38e6d09 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -371,8 +371,10 @@ fn (mut p Parser) fn_args() ([]table.Arg, bool) {
 			}
 			pos := p.tok.position()
 			mut arg_type := p.parse_type()
-			if is_mut && arg_type != table.t_type {
-				p.check_fn_mutable_arguments(arg_type, pos)
+			if is_mut {
+				if arg_type != table.t_type {
+					p.check_fn_mutable_arguments(arg_type, pos)
+				}
 				// if arg_type.is_ptr() {
 				// p.error('cannot mut')
 				// }
@@ -421,8 +423,10 @@ fn (mut p Parser) fn_args() ([]table.Arg, bool) {
 			}
 			pos := p.tok.position()
 			mut typ := p.parse_type()
-			if is_mut && typ != table.t_type {
-				p.check_fn_mutable_arguments(typ, pos)
+			if is_mut {
+				if typ != table.t_type {
+					p.check_fn_mutable_arguments(typ, pos)
+				}
 				typ = typ.set_nr_muls(1)
 			}
 			if is_variadic {
diff --git a/vlib/v/tests/generics_test.v b/vlib/v/tests/generics_test.v
index a0fb8a162d..982ba32a51 100644
--- a/vlib/v/tests/generics_test.v
+++ b/vlib/v/tests/generics_test.v
@@ -72,7 +72,7 @@ fn test_create() {
 	create<User>()
 	create<City>()
 	u := User{}
-	//gen_arg<User>(mut u)
+	gen_arg<User>(mut u)
 }
 
 /*