checker: do not allow auto (de)reference in PrefixExpr *; pref: disable parallel checker on arm linux for now

vlib/os/process_windows.c.v

@@ -30,13 +30,8 @@ fn failed_cfn_report_error(ok bool, label string) {
 	exit(1)
 }
 
-type PU32 = &u32
-
-// TODO: the PU32 alias is used to compensate for the wrong number of &/*
-// that V does when doing: `h := &&u32(p)`, which should have casted
-// p to a double pointer.
 fn close_valid_handle(p voidptr) {
-	h := &PU32(p)
+	h := &&u32(p)
 	if *h != &u32(0) {
 		C.CloseHandle(*h)
 		unsafe {

vlib/v/ast/table.v

@@ -848,7 +848,7 @@ fn (mut t Table) rewrite_already_registered_symbol(typ TypeSymbol, existing_idx
 		if existing_idx == string_type_idx {
 			// existing_type := t.type_symbols[existing_idx]
 			unsafe {
-				*existing_symbol = &TypeSymbol{
+				*existing_symbol = TypeSymbol{
 					...typ
 					kind:       existing_symbol.kind
 					idx:        existing_idx

vlib/v/ast/types.v

@@ -844,6 +844,12 @@ pub fn (t &TypeSymbol) str() string {
 	return t.name
 }
 
+// TODO why is this needed? str() returns incorrect amount of &
+pub fn (t &TypeSymbol) str_with_correct_nr_muls(n int) string {
+	prefix := strings.repeat(`&`, n)
+	return prefix + t.name
+}
+
 @[noreturn]
 fn (t &TypeSymbol) no_info_panic(fname string) {
 	panic('${fname}: no info for type: ${t.name}')

vlib/v/checker/assign.v

@@ -186,6 +186,7 @@ fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 				&& ((left.info as ast.IdentVar).share == .shared_t || left_type.has_flag(.shared_f))
 				&& c.table.sym(left_type).kind in [.array, .map, .struct]
 		}
+
 		if c.comptime.comptime_for_field_var != '' && mut left is ast.ComptimeSelector {
 			if c.comptime.has_different_types && node.right[i].is_literal()
 				&& !c.comptime.inside_comptime_if {
@@ -545,6 +546,19 @@ fn (mut c Checker) assign_stmt(mut node ast.AssignStmt) {
 			c.error('use `${mut_str}array2 ${node.op.str()} array1.clone()` instead of `${mut_str}array2 ${node.op.str()} array1` (or use `unsafe`)',
 				node.pos)
 		}
+
+		// Do not allow auto (de)reference in PrefixExpr
+		// e.g. `*ptr1 = ptr2`
+		if mut left is ast.PrefixExpr && left.op == .mul {
+			if left_type.nr_muls() != right_type.nr_muls() && !left_type.is_voidptr()
+				&& !right_type.is_voidptr() && right_type != ast.nil_type {
+				r := right_sym.str_with_correct_nr_muls(right_type.nr_muls())
+				l := left_sym.str_with_correct_nr_muls(left_type.nr_muls())
+				c.error('cannot use `${r}` (right side) as `${l}` (left side) in assignment',
+					node.pos)
+			}
+		}
+
 		if left_sym.kind == .array && right_sym.kind == .array {
 			right_info := right_sym.info as ast.Array
 			right_elem_type := c.table.unaliased_type(right_info.elem_type)

vlib/v/checker/tests/cannot_dereference_if_different_muls.out

@@ -0,0 +1,7 @@
+vlib/v/checker/tests/cannot_dereference_if_different_muls.vv:6:8: error: cannot use `&u64` (right side) as `u64` (left side) in assignment
+    4 |     unsafe {
+    5 |         mut ptr := &u64(page + higher_half)
+    6 |         *ptr = freelist_head
+      |              ^
+    7 |         freelist_head = ptr
+    8 |     }

vlib/v/checker/tests/cannot_dereference_if_different_muls.vv

@@ -0,0 +1,13 @@
+fn freelist_free(page u64) {
+	freelist_head := &u64(unsafe { nil })
+	higher_half := u64(0)
+	unsafe {
+		mut ptr := &u64(page + higher_half)
+		*ptr = freelist_head
+		freelist_head = ptr
+	}
+}
+
+fn main() {
+	freelist_free(0)
+}

vlib/v/pref/pref.v

@@ -1056,6 +1056,13 @@ pub fn parse_args_and_show_errors(known_external_commands []string, args []strin
 		}
 	}
 
+	// Disable parallel checker on arm64 windows and linux for now
+	$if linux || windows {
+		$if arm64 {
+			res.no_parallel = true
+		}
+	}
+
 	if res.out_name.ends_with('.o') {
 		res.is_o = true
 	}