From 3573030b9b61211e34983bbd08d4bca95c5d7051 Mon Sep 17 00:00:00 2001
From: Delyan Angelov <delian66@gmail.com>
Date: Fri, 10 Apr 2020 15:11:05 +0300
Subject: [PATCH] checker: fix error position for assignment expression

---
 vlib/v/checker/checker.v                                  | 2 +-
 .../tests/inout/void_function_assign_to_string.out        | 7 +++++++
 .../checker/tests/inout/void_function_assign_to_string.vv | 8 ++++++++
 vlib/v/parser/parser.v                                    | 3 ++-
 vlib/v/util/errors.v                                      | 8 ++++++--
 5 files changed, 24 insertions(+), 4 deletions(-)
 create mode 100644 vlib/v/checker/tests/inout/void_function_assign_to_string.out
 create mode 100644 vlib/v/checker/tests/inout/void_function_assign_to_string.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index f0917b0c9a..ec97a62f4c 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -215,7 +215,7 @@ fn (c mut Checker) assign_expr(assign_expr mut ast.AssignExpr) {
 	if !c.table.check(right_type, left_type) {
 		left_type_sym := c.table.get_type_symbol(left_type)
 		right_type_sym := c.table.get_type_symbol(right_type)
-		c.error('cannot assign `$right_type_sym.name` to `$left_type_sym.name`', assign_expr.pos)
+		c.error('cannot assign `$right_type_sym.name` to variable `${assign_expr.left.str()}` of type `$left_type_sym.name` ', assign_expr.pos)
 	}
 	c.check_expr_opt_call(assign_expr.val, right_type, true)
 }
diff --git a/vlib/v/checker/tests/inout/void_function_assign_to_string.out b/vlib/v/checker/tests/inout/void_function_assign_to_string.out
new file mode 100644
index 0000000000..1536611344
--- /dev/null
+++ b/vlib/v/checker/tests/inout/void_function_assign_to_string.out
@@ -0,0 +1,7 @@
+vlib/v/checker/tests/inout/void_function_assign_to_string.v:6:6: error: cannot assign `void` to variable `a` of type `string`  
+    4| fn main(){
+    5|     mut a := ''
+    6|     a = x(1,2) // hello
+               ^
+    7|     eprintln('a: $a')
+    8| }
diff --git a/vlib/v/checker/tests/inout/void_function_assign_to_string.vv b/vlib/v/checker/tests/inout/void_function_assign_to_string.vv
new file mode 100644
index 0000000000..839d84d00c
--- /dev/null
+++ b/vlib/v/checker/tests/inout/void_function_assign_to_string.vv
@@ -0,0 +1,8 @@
+fn x(x,y int) {
+
+}
+fn main(){
+	mut a := ''
+	a = x(1,2) // hello
+	eprintln('a: $a')
+}
diff --git a/vlib/v/parser/parser.v b/vlib/v/parser/parser.v
index e8c7e4777d..7d87e2bebb 100644
--- a/vlib/v/parser/parser.v
+++ b/vlib/v/parser/parser.v
@@ -461,6 +461,7 @@ pub fn (p mut Parser) stmt() ast.Stmt {
 pub fn (p mut Parser) assign_expr(left ast.Expr) ast.AssignExpr {
 	op := p.tok.kind
 	p.next()
+	pos := p.tok.position()
 	val := p.expr(0)
 	match left {
 		ast.IndexExpr {
@@ -473,7 +474,7 @@ pub fn (p mut Parser) assign_expr(left ast.Expr) ast.AssignExpr {
 		left: left
 		val: val
 		op: op
-		pos: p.tok.position()
+		pos: pos
 	}
 	return node
 }
diff --git a/vlib/v/util/errors.v b/vlib/v/util/errors.v
index 8a1929be7f..32c90b4adb 100644
--- a/vlib/v/util/errors.v
+++ b/vlib/v/util/errors.v
@@ -95,8 +95,12 @@ pub fn formatted_error(kind string /*error or warn*/, emsg string, filepath stri
 					}
 					continue
 				}
-				underline := '~'.repeat(pos.len)
-				pointerline << if emanager.support_color { term.bold(term.blue(underline)) } else { underline }
+				if pos.len > 1 {
+					underline := '~'.repeat(pos.len)
+					pointerline << if emanager.support_color { term.bold(term.blue(underline)) } else { underline }
+				}else{
+					pointerline << if emanager.support_color { term.bold(term.blue('^')) } else { '^' }
+				}
 				break
 			}
 			clines << '       ' + pointerline.join('')