v2: fix for position and check

vlib/v/ast/ast.v

@@ -341,6 +341,7 @@ pub:
 	cond   Expr
 	stmts  []Stmt
 	pos    token.Position
+	is_inf bool // `for {}`
 }
 
 pub struct ForInStmt {

vlib/v/checker/checker.v

@@ -273,7 +273,7 @@ fn (c mut Checker) stmt(node ast.Stmt) {
 			typ := c.expr(it.cond)
 			// typ_sym := c.table.get_type_symbol(typ)
 			// if typ_sym.kind != .bool {
-			if table.type_idx(typ) != table.bool_type_idx {
+			if !it.is_inf && table.type_idx(typ) != table.bool_type_idx {
 				c.error('non-bool used as for condition', it.pos)
 			}
 			for stmt in it.stmts {

vlib/v/parser/parser.v

@@ -91,7 +91,6 @@ pub fn parse_file(path string, table &table.Table) ast.File {
 	for p.tok.kind == .key_import {
 		imports << p.import_stmt()
 	}
-
 	// TODO: import only mode
 	for {
 		// res := s.scan()
@@ -893,11 +892,13 @@ fn (p mut Parser) for_statement() ast.Stmt {
 	// defer { p.close_scope() }
 	// Infinite loop
 	if p.tok.kind == .lcbr {
+		pos := p.tok.position()
 		stmts := p.parse_block()
 		p.close_scope()
 		return ast.ForStmt{
 			stmts: stmts
-			pos: p.tok.position()
+			pos: pos
+			is_inf: true
 		}
 	}
 	else if p.tok.kind == .key_mut {