parser: cleanup `&Type(x)` more, add fmt regression test

vlib/v/fmt/tests/pointer_casts_keep.vv

@@ -0,0 +1,30 @@
+struct Struct {}
+
+fn main() {
+	unsafe {
+		pb := &byte(0)
+		ppb := &&byte(0)
+		pppb := &&&byte(0)
+		ppppb := &&&&byte(0)
+		dump(voidptr(pb))
+		dump(voidptr(ppb))
+		dump(voidptr(pppb))
+		dump(voidptr(ppppb))
+		pc := &char(0)
+		ppc := &&char(0)
+		pppc := &&&char(0)
+		ppppc := &&&&char(0)
+		dump(voidptr(pc))
+		dump(voidptr(ppc))
+		dump(voidptr(pppc))
+		dump(voidptr(ppppc))
+		ps := &Struct(0)
+		pps := &&Struct(0)
+		ppps := &&&Struct(0)
+		pppps := &&&&Struct(0)
+		dump(voidptr(ps))
+		dump(voidptr(pps))
+		dump(voidptr(ppps))
+		dump(voidptr(pppps))
+	}
+}

vlib/v/parser/expr.v

@@ -170,7 +170,7 @@ pub fn (mut p Parser) check_expr(precedence int) ?ast.Expr {
 				node = p.name_expr()
 			} else if p.is_amp && p.peek_tok.kind == .rsbr && p.peek_token(3).kind != .lcbr {
 				pos := p.tok.position()
-				typ := p.parse_type().to_ptr()
+				typ := p.parse_type()
 				p.check(.lpar)
 				expr := p.expr(0)
 				p.check(.rpar)
@@ -577,8 +577,11 @@ fn (mut p Parser) prefix_expr() ast.Expr {
 	mut right := p.expr(int(token.Precedence.prefix))
 	p.is_amp = false
 	if mut right is ast.CastExpr && op == .amp {
+		// Handle &Type(x), as well as &&Type(x) etc:
+		mut new_cast_type := right.typ.to_ptr()
 		return ast.CastExpr{
 			...right
+			typ: new_cast_type
 			pos: pos.extend(right.pos)
 		}
 	}

vlib/v/parser/parser.v

@@ -2070,10 +2070,6 @@ pub fn (mut p Parser) name_expr() ast.Expr {
 			// TODO handle C.stat()
 			start_pos := p.tok.position()
 			mut to_typ := p.parse_type()
-			if p.is_amp {
-				// Handle `&Foo(0)`
-				to_typ = to_typ.to_ptr()
-			}
 			// this prevents inner casts to also have an `&`
 			// example: &Foo(malloc(int(num)))
 			// without the next line int would result in int*