parser: allow array cast syntax

vlib/v/checker/checker.v

@@ -3181,7 +3181,8 @@ fn (mut c Checker) cast_expr(mut node ast.CastExpr) ast.Type {
 		c.error('cannot cast string to `${tt}` outside `unsafe`, use ${tt}(s.str) instead',
 			node.pos)
 	} else if final_from_sym.kind == .array && !from_type.is_ptr() && to_type != ast.string_type
-		&& !(to_type.has_flag(.option) && from_type.idx() == to_type.idx()) {
+		&& !(to_type.has_flag(.option) && from_type.idx() == to_type.idx())
+		&& to_sym.kind != final_from_sym.kind {
 		ft := c.table.type_to_str(from_type)
 		tt := c.table.type_to_str(to_type)
 		c.error('cannot cast array `${ft}` to `${tt}`', node.pos)

vlib/v/parser/expr.v

@@ -195,10 +195,12 @@ fn (mut p Parser) check_expr(precedence int) !ast.Expr {
 			if p.expecting_type {
 				// parse json.decode type (`json.decode([]User, s)`)
 				node = p.name_expr()
-			} else if p.is_amp && p.peek_tok.kind == .rsbr {
+			} else if (p.is_amp && p.peek_tok.kind == .rsbr)
+				|| (p.peek_tok.kind == .rsbr && (p.peek_token(3).kind == .lpar
+				|| p.is_array_cast(3)) && p.tok.line_nr == p.peek_token(3).line_nr) {
 				mut n := 2
 				mut peek_n_tok := p.peek_token(n)
-				for peek_n_tok.kind in [.name, .dot] {
+				for peek_n_tok.kind in [.name, .dot, .lsbr, .rsbr] {
 					n++
 					peek_n_tok = p.peek_token(n)
 				}

vlib/v/parser/parser.v

@@ -539,28 +539,43 @@ fn (p &Parser) is_fn_type_decl() bool {
 	return true
 }
 
-fn (p &Parser) is_array_type() bool {
-	mut i := 1
+@[inline]
+fn (p &Parser) is_array_cast(offset int) bool {
+	name_offset := p.is_array_type_from_offset(offset)
+	if name_offset != -1 {
+		return p.peek_token(name_offset + 1).kind == .lpar
+	}
+	return false
+}
+
+@[inline]
+fn (p &Parser) is_array_type_from_offset(offset int) int {
 	mut tok := p.tok
 	line_nr := p.tok.line_nr
+	mut i := offset
 
 	for {
 		tok = p.peek_token(i)
 		if tok.line_nr != line_nr {
-			return false
+			return -1
 		}
 		if tok.kind in [.name, .amp] {
-			return true
+			return i
 		}
-		if tok.kind == .eof {
+		if tok.kind !in [.number, .name, .amp, .lsbr, .rsbr] {
 			break
 		}
 		i++
 		if tok.kind == .lsbr || tok.kind != .rsbr {
 			continue
 		}
 	}
-	return false
+	return -1
+}
+
+@[inline]
+fn (p &Parser) is_array_type() bool {
+	return p.is_array_type_from_offset(1) != -1
 }
 
 fn (mut p Parser) open_scope() {