Merge pull request #14477 from Vexu/fixes

Improve `@ptrCast` errors, fix some bugs

Author: andrewrk

doc/langref.html.in

@@ -8809,6 +8809,15 @@ pub const PrefetchOptions = struct {
       {#link|Optional Pointers#} are allowed. Casting an optional pointer which is {#link|null#}
       to a non-optional pointer invokes safety-checked {#link|Undefined Behavior#}.
       </p>
+      <p>
+      {#syntax#}@ptrCast{#endsyntax#} cannot be used for:
+      </p>
+      <ul>
+          <li>Removing {#syntax#}const{#endsyntax#} or {#syntax#}volatile{#endsyntax#} qualifier, use {#link|@qualCast#}.</li>
+          <li>Changing pointer address space, use {#link|@addrSpaceCast#}.</li>
+          <li>Increasing pointer alignment, use {#link|@alignCast#}.</li>
+          <li>Casting a non-slice pointer to a slice, use slicing syntax {#syntax#}ptr[start..end]{#endsyntax#}.</li>
+      </ul>
       {#header_close#}
 
       {#header_open|@ptrToInt#}
@@ -8821,6 +8830,13 @@ pub const PrefetchOptions = struct {
 
       {#header_close#}
 
+      {#header_open|@qualCast#}
+      <pre>{#syntax#}@qualCast(comptime DestType: type, value: anytype) DestType{#endsyntax#}</pre>
+      <p>
+      Remove {#syntax#}const{#endsyntax#} or {#syntax#}volatile{#endsyntax#} qualifier from a pointer.
+      </p>
+      {#header_close#}
+
       {#header_open|@rem#}
       <pre>{#syntax#}@rem(numerator: T, denominator: T) T{#endsyntax#}</pre>
       <p>

lib/std/child_process.zig

@@ -1164,7 +1164,7 @@ fn windowsCreateProcessPathExt(
         var app_name_unicode_string = windows.UNICODE_STRING{
             .Length = app_name_len_bytes,
             .MaximumLength = app_name_len_bytes,
-            .Buffer = @intToPtr([*]u16, @ptrToInt(app_name_wildcard.ptr)),
+            .Buffer = @qualCast([*:0]u16, app_name_wildcard.ptr),
         };
         const rc = windows.ntdll.NtQueryDirectoryFile(
             dir.fd,
@@ -1261,7 +1261,7 @@ fn windowsCreateProcessPathExt(
         var app_name_unicode_string = windows.UNICODE_STRING{
             .Length = app_name_len_bytes,
             .MaximumLength = app_name_len_bytes,
-            .Buffer = @intToPtr([*]u16, @ptrToInt(app_name_appended.ptr)),
+            .Buffer = @qualCast([*:0]u16, app_name_appended.ptr),
         };
 
         // Re-use the directory handle but this time we call with the appended app name

lib/std/fs.zig

@@ -1763,7 +1763,7 @@ pub const Dir = struct {
         var nt_name = w.UNICODE_STRING{
             .Length = path_len_bytes,
             .MaximumLength = path_len_bytes,
-            .Buffer = @intToPtr([*]u16, @ptrToInt(sub_path_w)),
+            .Buffer = @qualCast([*:0]u16, sub_path_w),
         };
         var attr = w.OBJECT_ATTRIBUTES{
             .Length = @sizeOf(w.OBJECT_ATTRIBUTES),

lib/std/os.zig

@@ -4513,7 +4513,7 @@ pub fn faccessatW(dirfd: fd_t, sub_path_w: [*:0]const u16, mode: u32, flags: u32
     var nt_name = windows.UNICODE_STRING{
         .Length = path_len_bytes,
         .MaximumLength = path_len_bytes,
-        .Buffer = @intToPtr([*]u16, @ptrToInt(sub_path_w)),
+        .Buffer = @qualCast([*:0]u16, sub_path_w),
     };
     var attr = windows.OBJECT_ATTRIBUTES{
         .Length = @sizeOf(windows.OBJECT_ATTRIBUTES),

lib/std/os/windows.zig

@@ -85,7 +85,7 @@ pub fn OpenFile(sub_path_w: []const u16, options: OpenFileOptions) OpenError!HAN
     var nt_name = UNICODE_STRING{
         .Length = path_len_bytes,
         .MaximumLength = path_len_bytes,
-        .Buffer = @intToPtr([*]u16, @ptrToInt(sub_path_w.ptr)),
+        .Buffer = @qualCast([*]u16, sub_path_w.ptr),
     };
     var attr = OBJECT_ATTRIBUTES{
         .Length = @sizeOf(OBJECT_ATTRIBUTES),
@@ -634,7 +634,7 @@ pub fn SetCurrentDirectory(path_name: []const u16) SetCurrentDirectoryError!void
     var nt_name = UNICODE_STRING{
         .Length = path_len_bytes,
         .MaximumLength = path_len_bytes,
-        .Buffer = @intToPtr([*]u16, @ptrToInt(path_name.ptr)),
+        .Buffer = @qualCast([*]u16, path_name.ptr),
     };
 
     const rc = ntdll.RtlSetCurrentDirectory_U(&nt_name);
@@ -766,7 +766,7 @@ pub fn ReadLink(dir: ?HANDLE, sub_path_w: []const u16, out_buffer: []u8) ReadLin
     var nt_name = UNICODE_STRING{
         .Length = path_len_bytes,
         .MaximumLength = path_len_bytes,
-        .Buffer = @intToPtr([*]u16, @ptrToInt(sub_path_w.ptr)),
+        .Buffer = @qualCast([*]u16, sub_path_w.ptr),
     };
     var attr = OBJECT_ATTRIBUTES{
         .Length = @sizeOf(OBJECT_ATTRIBUTES),
@@ -876,7 +876,7 @@ pub fn DeleteFile(sub_path_w: []const u16, options: DeleteFileOptions) DeleteFil
         .Length = path_len_bytes,
         .MaximumLength = path_len_bytes,
         // The Windows API makes this mutable, but it will not mutate here.
-        .Buffer = @intToPtr([*]u16, @ptrToInt(sub_path_w.ptr)),
+        .Buffer = @qualCast([*]u16, sub_path_w.ptr),
     };
 
     if (sub_path_w[0] == '.' and sub_path_w[1] == 0) {
@@ -1414,7 +1414,7 @@ pub fn sendmsg(
 }
 
 pub fn sendto(s: ws2_32.SOCKET, buf: [*]const u8, len: usize, flags: u32, to: ?*const ws2_32.sockaddr, to_len: ws2_32.socklen_t) i32 {
-    var buffer = ws2_32.WSABUF{ .len = @truncate(u31, len), .buf = @intToPtr([*]u8, @ptrToInt(buf)) };
+    var buffer = ws2_32.WSABUF{ .len = @truncate(u31, len), .buf = @qualCast([*]u8, buf) };
     var bytes_send: DWORD = undefined;
     if (ws2_32.WSASendTo(s, @ptrCast([*]ws2_32.WSABUF, &buffer), 1, &bytes_send, flags, to, @intCast(i32, to_len), null, null) == ws2_32.SOCKET_ERROR) {
         return ws2_32.SOCKET_ERROR;
@@ -1876,13 +1876,13 @@ pub fn eqlIgnoreCaseWTF16(a: []const u16, b: []const u16) bool {
     const a_string = UNICODE_STRING{
         .Length = a_bytes,
         .MaximumLength = a_bytes,
-        .Buffer = @intToPtr([*]u16, @ptrToInt(a.ptr)),
+        .Buffer = @qualCast([*]u16, a.ptr),
     };
     const b_bytes = @intCast(u16, b.len * 2);
     const b_string = UNICODE_STRING{
         .Length = b_bytes,
         .MaximumLength = b_bytes,
-        .Buffer = @intToPtr([*]u16, @ptrToInt(b.ptr)),
+        .Buffer = @qualCast([*]u16, b.ptr),
     };
     return ntdll.RtlEqualUnicodeString(&a_string, &b_string, TRUE) == TRUE;
 }

lib/std/zig/c_translation.zig

@@ -75,7 +75,7 @@ fn castPtr(comptime DestType: type, target: anytype) DestType {
     const source = ptrInfo(@TypeOf(target));
 
     if (source.is_const and !dest.is_const or source.is_volatile and !dest.is_volatile)
-        return @intToPtr(DestType, @ptrToInt(target))
+        return @qualCast(DestType, target)
     else if (@typeInfo(dest.child) == .Opaque)
         // dest.alignment would error out
         return @ptrCast(DestType, target)

src/AstGen.zig

@@ -2530,6 +2530,7 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .bit_size_of,
             .typeof_log2_int_type,
             .ptr_to_int,
+            .qual_cast,
             .align_of,
             .bool_to_int,
             .embed_file,
@@ -4278,7 +4279,34 @@ fn testDecl(
             var num_namespaces_out: u32 = 0;
             var capturing_namespace: ?*Scope.Namespace = null;
             while (true) switch (s.tag) {
-                .local_val, .local_ptr => unreachable, // a test cannot be in a local scope
+                .local_val => {
+                    const local_val = s.cast(Scope.LocalVal).?;
+                    if (local_val.name == name_str_index) {
+                        local_val.used = test_name_token;
+                        return astgen.failTokNotes(test_name_token, "cannot test a {s}", .{
+                            @tagName(local_val.id_cat),
+                        }, &[_]u32{
+                            try astgen.errNoteTok(local_val.token_src, "{s} declared here", .{
+                                @tagName(local_val.id_cat),
+                            }),
+                        });
+                    }
+                    s = local_val.parent;
+                },
+                .local_ptr => {
+                    const local_ptr = s.cast(Scope.LocalPtr).?;
+                    if (local_ptr.name == name_str_index) {
+                        local_ptr.used = test_name_token;
+                        return astgen.failTokNotes(test_name_token, "cannot test a {s}", .{
+                            @tagName(local_ptr.id_cat),
+                        }, &[_]u32{
+                            try astgen.errNoteTok(local_ptr.token_src, "{s} declared here", .{
+                                @tagName(local_ptr.id_cat),
+                            }),
+                        });
+                    }
+                    s = local_ptr.parent;
+                },
                 .gen_zir => s = s.cast(GenZir).?.parent,
                 .defer_normal, .defer_error => s = s.cast(Scope.Defer).?.parent,
                 .namespace, .enum_namespace => {
@@ -8010,6 +8038,7 @@ fn builtinCall(
         .float_cast   => return typeCast(gz, scope, ri, node, params[0], params[1], .float_cast),
         .int_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .int_cast),
         .ptr_cast     => return typeCast(gz, scope, ri, node, params[0], params[1], .ptr_cast),
+        .qual_cast    => return typeCast(gz, scope, ri, node, params[0], params[1], .qual_cast),
         .truncate     => return typeCast(gz, scope, ri, node, params[0], params[1], .truncate),
         // zig fmt: on
 
@@ -8692,6 +8721,7 @@ fn callExpr(
         defer arg_block.unstack();
 
         // `call_inst` is reused to provide the param type.
+        arg_block.rl_ty_inst = call_inst;
         const arg_ref = try expr(&arg_block, &arg_block.base, .{ .rl = .{ .coerced_ty = call_inst }, .ctx = .fn_arg }, param_node);
         _ = try arg_block.addBreak(.break_inline, call_index, arg_ref);
 
@@ -10840,7 +10870,12 @@ const GenZir = struct {
         // we emit ZIR for the block break instructions to have the result values,
         // and then rvalue() on that to pass the value to the result location.
         switch (parent_ri.rl) {
-            .ty, .coerced_ty => |ty_inst| {
+            .coerced_ty => |ty_inst| {
+                // Type coercion needs to happend before breaks.
+                gz.rl_ty_inst = ty_inst;
+                gz.break_result_info = .{ .rl = .{ .ty = ty_inst } };
+            },
+            .ty => |ty_inst| {
                 gz.rl_ty_inst = ty_inst;
                 gz.break_result_info = parent_ri;
             },

src/BuiltinFn.zig

@@ -75,6 +75,7 @@ pub const Tag = enum {
     prefetch,
     ptr_cast,
     ptr_to_int,
+    qual_cast,
     rem,
     return_address,
     select,
@@ -674,6 +675,13 @@ pub const list = list: {
                 .param_count = 1,
             },
         },
+        .{
+            "@qualCast",
+            .{
+                .tag = .qual_cast,
+                .param_count = 2,
+            },
+        },
         .{
             "@rem",
             .{