checker: check if BranchStmt is in a loop

vlib/v/checker/checker.v

@@ -31,6 +31,7 @@ mut:
 	//assigned_var_name string
 	// fn_decl        ast.FnDecl
 	pref           &pref.Preferences // Preferences shared from V struct
+	in_for_count   int // if checker is currently in an for loop
 }
 
 pub fn new_checker(table &table.Table, pref &pref.Preferences) Checker {
@@ -597,6 +598,11 @@ fn (c mut Checker) stmt(node ast.Stmt) {
 		ast.Block {
 			c.stmts(it.stmts)
 		}
+		ast.BranchStmt {
+			if c.in_for_count == 0 {
+				c.error('$it.tok.lit statement not within a loop', it.tok.position())
+			}
+		}
 		// ast.Attr {}
 		ast.CompIf {
 			// c.expr(it.cond)
@@ -660,6 +666,7 @@ fn (c mut Checker) stmt(node ast.Stmt) {
 			c.stmts(it.stmts)
 		}
 		ast.ForStmt {
+			c.in_for_count++
 			typ := c.expr(it.cond)
 			if !it.is_inf && table.type_idx(typ) != table.bool_type_idx {
 				c.error('non-bool used as for condition', it.pos)
@@ -667,15 +674,19 @@ fn (c mut Checker) stmt(node ast.Stmt) {
 			// TODO: update loop var type
 			// how does this work currenly?
 			c.stmts(it.stmts)
+			c.in_for_count--
 		}
 		ast.ForCStmt {
+			c.in_for_count++
 			c.stmt(it.init)
 			c.expr(it.cond)
 			// c.stmt(it.inc)
 			c.expr(it.inc)
 			c.stmts(it.stmts)
+			c.in_for_count--
 		}
 		ast.ForInStmt {
+			c.in_for_count++
 			typ := c.expr(it.cond)
 			if it.is_range {
 				c.expr(it.high)
@@ -690,7 +701,7 @@ fn (c mut Checker) stmt(node ast.Stmt) {
 						}
 						else {
 							table.int_type}
-	}
+					}
 					it.key_type = key_type
 					scope.update_var_type(it.key_var, key_type)
 				}
@@ -705,6 +716,7 @@ fn (c mut Checker) stmt(node ast.Stmt) {
 				scope.update_var_type(it.val_var, value_type)
 			}
 			c.stmts(it.stmts)
+			c.in_for_count--
 		}
 		ast.GoStmt{
 			c.expr(it.call_expr)

vlib/v/scanner/scanner.v

@@ -379,7 +379,7 @@ pub fn (s mut Scanner) scan() token.Token {
 		// Check if not .eof to prevent panic
 		next_char := if s.pos + 1 < s.text.len { s.text[s.pos + 1] } else { `\0` }
 		if token.is_key(name) {
-			return s.new_token(token.key_to_token(name), '')
+			return s.new_token(token.key_to_token(name), name)
 		}
 		// 'asdf $b' => "b" is the last name in the string, dont start parsing string
 		// at the next ', skip it
@@ -1019,7 +1019,7 @@ pub fn (s &Scanner) error(msg string) {
 	pos := token.Position{
 		line_nr: s.line_nr
 		pos: s.pos
-	}	 
+	}
 	eprintln(util.formated_error('error', msg, s.file_path, pos))
 	exit(1)
 }