Add opaque syntax that allows declarations

doc/docgen.zig

@@ -808,6 +808,7 @@ fn tokenizeAndPrintRaw(docgen_tokenizer: *Tokenizer, out: anytype, source_token:
             .Keyword_noalias,
             .Keyword_noinline,
             .Keyword_nosuspend,
+            .Keyword_opaque,
             .Keyword_or,
             .Keyword_orelse,
             .Keyword_packed,

doc/langref.html.in

@@ -1988,7 +1988,7 @@ test "null terminated array" {
               <li>Supports slice syntax: {#syntax#}ptr[start..end]{#endsyntax#}</li>
               <li>Supports pointer arithmetic: {#syntax#}ptr + x{#endsyntax#}, {#syntax#}ptr - x{#endsyntax#}</li>
               <li>{#syntax#}T{#endsyntax#} must have a known size, which means that it cannot be
-              {#syntax#}c_void{#endsyntax#} or any other {#link|opaque type|Opaque Types#}.</li>
+              {#syntax#}c_void{#endsyntax#} or any other {#link|opaque type|opaque#}.</li>
             </ul>
           </li>
       </ul>
@@ -5545,7 +5545,7 @@ test "turn HashMap into a set with void" {
       </p>
       <p>
       {#syntax#}void{#endsyntax#} is distinct from {#syntax#}c_void{#endsyntax#}, which is defined like this:
-              {#syntax#}pub const c_void = @Type(.Opaque);{#endsyntax#}.
+              {#syntax#}pub const c_void = opaque {};{#endsyntax#}.
                   {#syntax#}void{#endsyntax#} has a known size of 0 bytes, and {#syntax#}c_void{#endsyntax#} has an unknown, but non-zero, size.
       </p>
       <p>
@@ -8471,7 +8471,7 @@ test "integer truncation" {
           <li>{#link|Error Set Type#}</li>
           <li>{#link|Error Union Type#}</li>
           <li>{#link|Vectors#}</li>
-          <li>{#link|Opaque Types#}</li>
+          <li>{#link|opaque#}</li>
           <li>{#link|@Frame#}</li>
           <li>{#syntax#}anyframe{#endsyntax#}</li>
           <li>{#link|struct#}</li>
@@ -8547,17 +8547,18 @@ fn foo(comptime T: type, ptr: *T) T {
       {#header_close#}
       {#header_close#}
 
-      {#header_open|Opaque Types#}
+      {#header_open|opaque#}
       <p>
-      {#syntax#}@Type(.Opaque){#endsyntax#} creates a new type with an unknown (but non-zero) size and alignment.
+      {#syntax#}opaque {}{#endsyntax#} declares a new type with an unknown (but non-zero) size and alignment.
+      It can have declarations like structs, unions, or enums.
       </p>
       <p>
       This is typically used for type safety when interacting with C code that does not expose struct details.
       Example:
       </p>
       {#code_begin|test_err|expected type '*Derp', found '*Wat'#}
-const Derp = @Type(.Opaque);
-const Wat = @Type(.Opaque);
+const Derp = opaque {};
+const Wat = opaque {};
 
 extern fn bar(d: *Derp) void;
 fn foo(w: *Wat) callconv(.C) void {
@@ -11193,7 +11194,7 @@ PtrTypeStart
 ContainerDeclAuto &lt;- ContainerDeclType LBRACE ContainerMembers RBRACE
 
 ContainerDeclType
-    &lt;- (KEYWORD_struct / KEYWORD_enum) (LPAREN Expr RPAREN)?
+    &lt;- (KEYWORD_struct / KEYWORD_enum / KEYWORD_opaque) (LPAREN Expr RPAREN)?
      / KEYWORD_union (LPAREN (KEYWORD_enum (LPAREN Expr RPAREN)? / Expr) RPAREN)?
 
 # Alignment
@@ -11340,6 +11341,7 @@ KEYWORD_inline      &lt;- 'inline'      end_of_word
 KEYWORD_noalias     &lt;- 'noalias'     end_of_word
 KEYWORD_nosuspend   &lt;- 'nosuspend'   end_of_word
 KEYWORD_null        &lt;- 'null'        end_of_word
+KEYWORD_opaque      &lt;- 'opaque'      end_of_word
 KEYWORD_or          &lt;- 'or'          end_of_word
 KEYWORD_orelse      &lt;- 'orelse'      end_of_word
 KEYWORD_packed      &lt;- 'packed'      end_of_word
@@ -11368,7 +11370,7 @@ keyword &lt;- KEYWORD_align / KEYWORD_and / KEYWORD_anyframe / KEYWORD_anytype
          / KEYWORD_defer / KEYWORD_else / KEYWORD_enum / KEYWORD_errdefer
          / KEYWORD_error / KEYWORD_export / KEYWORD_extern / KEYWORD_false
          / KEYWORD_fn / KEYWORD_for / KEYWORD_if / KEYWORD_inline
-         / KEYWORD_noalias / KEYWORD_null / KEYWORD_or
+         / KEYWORD_noalias / KEYWORD_null / KEYWORD_opaque / KEYWORD_or
          / KEYWORD_orelse / KEYWORD_packed / KEYWORD_pub
          / KEYWORD_resume / KEYWORD_return / KEYWORD_linksection
          / KEYWORD_struct / KEYWORD_suspend

lib/std/builtin.zig

@@ -199,7 +199,7 @@ pub const TypeInfo = union(enum) {
     Union: Union,
     Fn: Fn,
     BoundFn: Fn,
-    Opaque: void,
+    Opaque: Opaque,
     Frame: Frame,
     AnyFrame: AnyFrame,
     Vector: Vector,
@@ -360,6 +360,12 @@ pub const TypeInfo = union(enum) {
         args: []const FnArg,
     };
 
+    /// This data structure is used by the Zig language code generation and
+    /// therefore must be kept in sync with the compiler implementation.
+    pub const Opaque = struct {
+        decls: []const Declaration,
+    };
+
     /// This data structure is used by the Zig language code generation and
     /// therefore must be kept in sync with the compiler implementation.
     pub const Frame = struct {

lib/std/c.zig

@@ -329,8 +329,8 @@ pub extern "c" fn pthread_cond_signal(cond: *pthread_cond_t) c_int;
 pub extern "c" fn pthread_cond_broadcast(cond: *pthread_cond_t) c_int;
 pub extern "c" fn pthread_cond_destroy(cond: *pthread_cond_t) c_int;
 
-pub const pthread_t = *@Type(.Opaque);
-pub const FILE = @Type(.Opaque);
+pub const pthread_t = *opaque {};
+pub const FILE = opaque {};
 
 pub extern "c" fn dlopen(path: [*:0]const u8, mode: c_int) ?*c_void;
 pub extern "c" fn dlclose(handle: *c_void) c_int;

lib/std/os/linux/bpf/kern.zig

@@ -12,28 +12,28 @@ const in_bpf_program = switch (std.builtin.arch) {
 
 pub const helpers = if (in_bpf_program) @import("helpers.zig") else struct {};
 
-pub const BpfSock = @Type(.Opaque);
-pub const BpfSockAddr = @Type(.Opaque);
-pub const FibLookup = @Type(.Opaque);
-pub const MapDef = @Type(.Opaque);
-pub const PerfEventData = @Type(.Opaque);
-pub const PerfEventValue = @Type(.Opaque);
-pub const PidNsInfo = @Type(.Opaque);
-pub const SeqFile = @Type(.Opaque);
-pub const SkBuff = @Type(.Opaque);
-pub const SkMsgMd = @Type(.Opaque);
-pub const SkReusePortMd = @Type(.Opaque);
-pub const Sock = @Type(.Opaque);
-pub const SockAddr = @Type(.Opaque);
-pub const SockOps = @Type(.Opaque);
-pub const SockTuple = @Type(.Opaque);
-pub const SpinLock = @Type(.Opaque);
-pub const SysCtl = @Type(.Opaque);
-pub const Tcp6Sock = @Type(.Opaque);
-pub const TcpRequestSock = @Type(.Opaque);
-pub const TcpSock = @Type(.Opaque);
-pub const TcpTimewaitSock = @Type(.Opaque);
-pub const TunnelKey = @Type(.Opaque);
-pub const Udp6Sock = @Type(.Opaque);
-pub const XdpMd = @Type(.Opaque);
-pub const XfrmState = @Type(.Opaque);
+pub const BpfSock = opaque {};
+pub const BpfSockAddr = opaque {};
+pub const FibLookup = opaque {};
+pub const MapDef = opaque {};
+pub const PerfEventData = opaque {};
+pub const PerfEventValue = opaque {};
+pub const PidNsInfo = opaque {};
+pub const SeqFile = opaque {};
+pub const SkBuff = opaque {};
+pub const SkMsgMd = opaque {};
+pub const SkReusePortMd = opaque {};
+pub const Sock = opaque {};
+pub const SockAddr = opaque {};
+pub const SockOps = opaque {};
+pub const SockTuple = opaque {};
+pub const SpinLock = opaque {};
+pub const SysCtl = opaque {};
+pub const Tcp6Sock = opaque {};
+pub const TcpRequestSock = opaque {};
+pub const TcpSock = opaque {};
+pub const TcpTimewaitSock = opaque {};
+pub const TunnelKey = opaque {};
+pub const Udp6Sock = opaque {};
+pub const XdpMd = opaque {};
+pub const XfrmState = opaque {};

lib/std/os/uefi.zig

@@ -17,7 +17,7 @@ pub var handle: Handle = undefined;
 pub var system_table: *tables.SystemTable = undefined;
 
 /// A handle to an event structure.
-pub const Event = *@Type(.Opaque);
+pub const Event = *opaque {};
 
 /// GUIDs must be align(8)
 pub const Guid = extern struct {
@@ -51,7 +51,7 @@ pub const Guid = extern struct {
 };
 
 /// An EFI Handle represents a collection of related interfaces.
-pub const Handle = *@Type(.Opaque);
+pub const Handle = *opaque {};
 
 /// This structure represents time information.
 pub const Time = extern struct {
@@ -108,4 +108,4 @@ pub const TimeCapabilities = extern struct {
 };
 
 /// File Handle as specified in the EFI Shell Spec
-pub const FileHandle = *@Type(.Opaque);
+pub const FileHandle = *opaque {};

lib/std/os/uefi/protocols/hii.zig

@@ -6,7 +6,7 @@
 const uefi = @import("std").os.uefi;
 const Guid = uefi.Guid;
 
-pub const HIIHandle = *@Type(.Opaque);
+pub const HIIHandle = *opaque {};
 
 /// The header found at the start of each package.
 pub const HIIPackageHeader = packed struct {

lib/std/os/windows/bits.zig

@@ -32,16 +32,16 @@ pub const UCHAR = u8;
 pub const FLOAT = f32;
 pub const HANDLE = *c_void;
 pub const HCRYPTPROV = ULONG_PTR;
-pub const HBRUSH = *@Type(.Opaque);
-pub const HCURSOR = *@Type(.Opaque);
-pub const HICON = *@Type(.Opaque);
-pub const HINSTANCE = *@Type(.Opaque);
-pub const HMENU = *@Type(.Opaque);
-pub const HMODULE = *@Type(.Opaque);
-pub const HWND = *@Type(.Opaque);
-pub const HDC = *@Type(.Opaque);
-pub const HGLRC = *@Type(.Opaque);
-pub const FARPROC = *@Type(.Opaque);
+pub const HBRUSH = *opaque {};
+pub const HCURSOR = *opaque {};
+pub const HICON = *opaque {};
+pub const HINSTANCE = *opaque {};
+pub const HMENU = *opaque {};
+pub const HMODULE = *opaque {};
+pub const HWND = *opaque {};
+pub const HDC = *opaque {};
+pub const HGLRC = *opaque {};
+pub const FARPROC = *opaque {};
 pub const INT = c_int;
 pub const LPBYTE = *BYTE;
 pub const LPCH = *CHAR;
@@ -81,7 +81,7 @@ pub const WPARAM = usize;
 pub const LPARAM = ?*c_void;
 pub const LRESULT = ?*c_void;
 
-pub const va_list = *@Type(.Opaque);
+pub const va_list = *opaque {};
 
 pub const TRUE = 1;
 pub const FALSE = 0;
@@ -1175,10 +1175,10 @@ pub const UNICODE_STRING = extern struct {
     Buffer: [*]WCHAR,
 };
 
-const ACTIVATION_CONTEXT_DATA = @Type(.Opaque);
-const ASSEMBLY_STORAGE_MAP = @Type(.Opaque);
-const FLS_CALLBACK_INFO = @Type(.Opaque);
-const RTL_BITMAP = @Type(.Opaque);
+const ACTIVATION_CONTEXT_DATA = opaque {};
+const ASSEMBLY_STORAGE_MAP = opaque {};
+const FLS_CALLBACK_INFO = opaque {};
+const RTL_BITMAP = opaque {};
 pub const PRTL_BITMAP = *RTL_BITMAP;
 const KAFFINITY = usize;
 

lib/std/os/windows/ws2_32.zig

@@ -5,7 +5,7 @@
 // and substantial portions of the software.
 usingnamespace @import("bits.zig");
 
-pub const SOCKET = *@Type(.Opaque);
+pub const SOCKET = *opaque {};
 pub const INVALID_SOCKET = @intToPtr(SOCKET, ~@as(usize, 0));
 pub const SOCKET_ERROR = -1;
 

lib/std/zig/ast.zig

@@ -288,7 +288,7 @@ pub const Error = union(enum) {
     pub const ExpectedVarDecl = SingleTokenError("Expected variable declaration, found '{}'");
     pub const ExpectedFn = SingleTokenError("Expected function, found '{}'");
     pub const ExpectedReturnType = SingleTokenError("Expected 'var' or return type expression, found '{}'");
-    pub const ExpectedAggregateKw = SingleTokenError("Expected '" ++ Token.Id.Keyword_struct.symbol() ++ "', '" ++ Token.Id.Keyword_union.symbol() ++ "', or '" ++ Token.Id.Keyword_enum.symbol() ++ "', found '{}'");
+    pub const ExpectedAggregateKw = SingleTokenError("Expected '" ++ Token.Id.Keyword_struct.symbol() ++ "', '" ++ Token.Id.Keyword_union.symbol() ++ "', '" ++ Token.Id.Keyword_enum.symbol() ++ "', or '" ++ Token.Id.Keyword_opaque.symbol() ++ "', found '{}'");
     pub const ExpectedEqOrSemi = SingleTokenError("Expected '=' or ';', found '{}'");
     pub const ExpectedSemiOrLBrace = SingleTokenError("Expected ';' or '{{', found '{}'");
     pub const ExpectedSemiOrElse = SingleTokenError("Expected ';' or 'else', found '{}'");

lib/std/zig/parse.zig

@@ -2896,11 +2896,12 @@ const Parser = struct {
     ///     <- KEYWORD_struct
     ///      / KEYWORD_enum (LPAREN Expr RPAREN)?
     ///      / KEYWORD_union (LPAREN (KEYWORD_enum (LPAREN Expr RPAREN)? / Expr) RPAREN)?
+    ///      / KEYWORD_opaque
     fn parseContainerDeclType(p: *Parser) !?ContainerDeclType {
         const kind_token = p.nextToken();
 
         const init_arg_expr = switch (p.token_ids[kind_token]) {
-            .Keyword_struct => Node.ContainerDecl.InitArg{ .None = {} },
+            .Keyword_struct, .Keyword_opaque => Node.ContainerDecl.InitArg{ .None = {} },
             .Keyword_enum => blk: {
                 if (p.eatToken(.LParen) != null) {
                     const expr = try p.expectNode(parseExpr, .{

lib/std/zig/render.zig

@@ -1492,7 +1492,19 @@ fn renderExpression(
 
             // TODO remove after 0.7.0 release
             if (mem.eql(u8, tree.tokenSlice(builtin_call.builtin_token), "@OpaqueType"))
-                return ais.writer().writeAll("@Type(.Opaque)");
+                return ais.writer().writeAll("opaque {}");
+
+            // TODO remove after 0.7.0 release
+            {
+                const params = builtin_call.paramsConst();
+                if (mem.eql(u8, tree.tokenSlice(builtin_call.builtin_token), "@Type") and
+                    params.len == 1)
+                {
+                    if (params[0].castTag(.EnumLiteral)) |enum_literal|
+                        if (mem.eql(u8, tree.tokenSlice(enum_literal.name), "Opaque"))
+                            return ais.writer().writeAll("opaque {}");
+                }
+            }
 
             try renderToken(tree, ais, builtin_call.builtin_token, Space.None); // @name
 

lib/std/zig/tokenizer.zig

@@ -47,6 +47,7 @@ pub const Token = struct {
         .{ "noinline", .Keyword_noinline },
         .{ "nosuspend", .Keyword_nosuspend },
         .{ "null", .Keyword_null },
+        .{ "opaque", .Keyword_opaque },
         .{ "or", .Keyword_or },
         .{ "orelse", .Keyword_orelse },
         .{ "packed", .Keyword_packed },
@@ -173,6 +174,7 @@ pub const Token = struct {
         Keyword_noinline,
         Keyword_nosuspend,
         Keyword_null,
+        Keyword_opaque,
         Keyword_or,
         Keyword_orelse,
         Keyword_packed,
@@ -296,6 +298,7 @@ pub const Token = struct {
                 .Keyword_noinline => "noinline",
                 .Keyword_nosuspend => "nosuspend",
                 .Keyword_null => "null",
+                .Keyword_opaque => "opaque",
                 .Keyword_or => "or",
                 .Keyword_orelse => "orelse",
                 .Keyword_packed => "packed",