From a0ca68ce3f50982186cc047d36fe8c846d2ff240 Mon Sep 17 00:00:00 2001
From: Alexander Medvednikov <alexander@medvednikov.com>
Date: Tue, 5 May 2020 15:26:42 +0200
Subject: [PATCH] checker: do not allow `string(int)`

---
 vlib/os/os_nix.c.v       | 2 +-
 vlib/v/ast/ast.v         | 1 +
 vlib/v/checker/checker.v | 4 ++++
 vlib/v/parser/parser.v   | 1 +
 vlib/v/table/atypes.v    | 3 ++-
 5 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/vlib/os/os_nix.c.v b/vlib/os/os_nix.c.v
index 70ecb81424..1bdccd3ed6 100644
--- a/vlib/os/os_nix.c.v
+++ b/vlib/os/os_nix.c.v
@@ -18,7 +18,7 @@ const (
 
 fn C.symlink(charptr, charptr) int
 
-fn init_os_args(argc int, argv &byteptr) []string {
+fn init_os_args(argc int, argv &&byte) []string {
 	mut args := []string{}
 	//mut args := []string(make(0, argc, sizeof(string)))
 	//mut args := []string{len:argc}
diff --git a/vlib/v/ast/ast.v b/vlib/v/ast/ast.v
index 254d3638ff..df6afb00db 100644
--- a/vlib/v/ast/ast.v
+++ b/vlib/v/ast/ast.v
@@ -678,6 +678,7 @@ pub:
 	expr      Expr // `buf`
 	arg       Expr // `n` in `string(buf, n)`
 	typ       table.Type // `string`
+	pos token.Position
 mut:
 	typname   string
 	expr_type table.Type // `byteptr`
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 8ff5b6f45f..81abf3e21d 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -1516,6 +1516,10 @@ pub fn (mut c Checker) expr(node ast.Expr) table.Type {
 				c.expr(it.arg)
 			}
 			it.typname = c.table.get_type_symbol(it.typ).name
+			if it.typ == table.string_type && !it.has_arg && it.expr_type.is_number() && !it.expr_type.is_ptr() {
+				// s := c.table.get_type_symbol(it.expr_type)
+				c.error('use `number.str()` instead of `string(number)`', it.pos)
+			}
 			return it.typ
 		}
 		ast.CallExpr {
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index 49fae86e7b..0a52a1bc4c 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -674,6 +674,7 @@ pub fn (mut p Parser) name_expr() ast.Expr {
 				expr: expr
 				arg: arg
 				has_arg: has_arg
+				pos: p.tok.position()
 			}
 			p.expr_mod = ''
 			return node
diff --git a/vlib/v/table/atypes.v b/vlib/v/table/atypes.v
index f1507f927d..f130a11547 100644
--- a/vlib/v/table/atypes.v
+++ b/vlib/v/table/atypes.v
@@ -195,7 +195,8 @@ pub const (
 	signed_integer_type_idxs   = [i8_type_idx, i16_type_idx, int_type_idx, i64_type_idx]
 	unsigned_integer_type_idxs = [byte_type_idx, u16_type_idx, u32_type_idx, u64_type_idx]
 	float_type_idxs            = [f32_type_idx, f64_type_idx]
-	number_type_idxs           = [i8_type_idx, i16_type_idx, int_type_idx, i64_type_idx, byte_type_idx,
+	number_type_idxs           = [i8_type_idx, i16_type_idx, int_type_idx,
+		i64_type_idx, byte_type_idx,
 		u16_type_idx,
 		u32_type_idx,
 		u64_type_idx,