Sema: fix typeInfo decls with usingnamespace

Closes ziglang#12403

Author: Vexu

src/Module.zig

@@ -528,10 +528,10 @@ pub const Decl = struct {
     /// Decl is marked alive, then it sends the Decl to the linker. Otherwise it
     /// deletes the Decl on the spot.
     alive: bool,
-    /// Whether the Decl is a `usingnamespace` declaration.
-    is_usingnamespace: bool,
     /// If true `name` is already fully qualified.
     name_fully_qualified: bool = false,
+    /// What kind of a declaration is this.
+    kind: Kind,
 
     /// Represents the position of the code in the output file.
     /// This is populated regardless of semantic analysis and code generation.
@@ -551,6 +551,14 @@ pub const Decl = struct {
     /// typed_value may need to be regenerated.
     dependencies: DepsTable = .{},
 
+    pub const Kind = enum {
+        @"usingnamespace",
+        @"test",
+        @"comptime",
+        named,
+        anon,
+    };
+
     pub const Index = enum(u32) {
         _,
 
@@ -4438,7 +4446,7 @@ fn semaDecl(mod: *Module, decl_index: Decl.Index) !bool {
     // not the struct itself.
     try sema.resolveTypeLayout(decl_tv.ty);
 
-    if (decl.is_usingnamespace) {
+    if (decl.kind == .@"usingnamespace") {
         if (!decl_tv.ty.eql(Type.type, mod)) {
             return sema.fail(&block_scope, ty_src, "expected type, found {}", .{
                 decl_tv.ty.fmt(mod),
@@ -4964,42 +4972,47 @@ fn scanDecl(iter: *ScanDeclIter, decl_sub_index: usize, flags: u4) Allocator.Err
 
     // Every Decl needs a name.
     var is_named_test = false;
+    var kind: Decl.Kind = .named;
     const decl_name: [:0]const u8 = switch (decl_name_index) {
         0 => name: {
             if (export_bit) {
                 const i = iter.usingnamespace_index;
                 iter.usingnamespace_index += 1;
+                kind = .@"usingnamespace";
                 break :name try std.fmt.allocPrintZ(gpa, "usingnamespace_{d}", .{i});
             } else {
                 const i = iter.comptime_index;
                 iter.comptime_index += 1;
+                kind = .@"comptime";
                 break :name try std.fmt.allocPrintZ(gpa, "comptime_{d}", .{i});
             }
         },
         1 => name: {
             const i = iter.unnamed_test_index;
             iter.unnamed_test_index += 1;
+            kind = .@"test";
             break :name try std.fmt.allocPrintZ(gpa, "test_{d}", .{i});
         },
         2 => name: {
             is_named_test = true;
             const test_name = zir.nullTerminatedString(decl_doccomment_index);
+            kind = .@"test";
             break :name try std.fmt.allocPrintZ(gpa, "decltest.{s}", .{test_name});
         },
         else => name: {
             const raw_name = zir.nullTerminatedString(decl_name_index);
             if (raw_name.len == 0) {
                 is_named_test = true;
                 const test_name = zir.nullTerminatedString(decl_name_index + 1);
+                kind = .@"test";
                 break :name try std.fmt.allocPrintZ(gpa, "test.{s}", .{test_name});
             } else {
                 break :name try gpa.dupeZ(u8, raw_name);
             }
         },
     };
     const is_exported = export_bit and decl_name_index != 0;
-    const is_usingnamespace = export_bit and decl_name_index == 0;
-    if (is_usingnamespace) try namespace.usingnamespace_set.ensureUnusedCapacity(gpa, 1);
+    if (kind == .@"usingnamespace") try namespace.usingnamespace_set.ensureUnusedCapacity(gpa, 1);
 
     // We create a Decl for it regardless of analysis status.
     const gop = try namespace.decls.getOrPutContextAdapted(
@@ -5012,8 +5025,9 @@ fn scanDecl(iter: *ScanDeclIter, decl_sub_index: usize, flags: u4) Allocator.Err
     if (!gop.found_existing) {
         const new_decl_index = try mod.allocateNewDecl(namespace, decl_node, iter.parent_decl.src_scope);
         const new_decl = mod.declPtr(new_decl_index);
+        new_decl.kind = kind;
         new_decl.name = decl_name;
-        if (is_usingnamespace) {
+        if (kind == .@"usingnamespace") {
             namespace.usingnamespace_set.putAssumeCapacity(new_decl_index, is_pub);
         }
         log.debug("scan new {*} ({s}) into {*}", .{ new_decl, decl_name, namespace });
@@ -5058,7 +5072,6 @@ fn scanDecl(iter: *ScanDeclIter, decl_sub_index: usize, flags: u4) Allocator.Err
         }
         new_decl.is_pub = is_pub;
         new_decl.is_exported = is_exported;
-        new_decl.is_usingnamespace = is_usingnamespace;
         new_decl.has_align = has_align;
         new_decl.has_linksection_or_addrspace = has_linksection_or_addrspace;
         new_decl.zir_decl_index = @intCast(u32, decl_sub_index);
@@ -5076,7 +5089,7 @@ fn scanDecl(iter: *ScanDeclIter, decl_sub_index: usize, flags: u4) Allocator.Err
 
     decl.is_pub = is_pub;
     decl.is_exported = is_exported;
-    decl.is_usingnamespace = is_usingnamespace;
+    decl.kind = kind;
     decl.has_align = has_align;
     decl.has_linksection_or_addrspace = has_linksection_or_addrspace;
     decl.zir_decl_index = @intCast(u32, decl_sub_index);
@@ -5635,7 +5648,7 @@ pub fn allocateNewDecl(
         .has_linksection_or_addrspace = false,
         .has_align = false,
         .alive = false,
-        .is_usingnamespace = false,
+        .kind = .anon,
     };
 
     return decl_and_index.decl_index;

src/Sema.zig

@@ -16217,11 +16217,54 @@ fn typeInfoDecls(
     };
     try sema.queueFullTypeResolution(try declaration_ty.copy(sema.arena));
 
-    const decls_len = if (opt_namespace) |ns| ns.decls.count() else 0;
-    const decls_vals = try decls_anon_decl.arena().alloc(Value, decls_len);
-    for (decls_vals) |*decls_val, i| {
-        const decl_index = opt_namespace.?.decls.keys()[i];
+    var decl_vals = std.ArrayList(Value).init(sema.gpa);
+    defer decl_vals.deinit();
+
+    var seen_namespaces = std.AutoHashMap(*Namespace, void).init(sema.gpa);
+    defer seen_namespaces.deinit();
+
+    if (opt_namespace) |some| {
+        try sema.typeInfoNamespaceDecls(block, decls_anon_decl.arena(), some, &decl_vals, &seen_namespaces);
+    }
+
+    const new_decl = try decls_anon_decl.finish(
+        try Type.Tag.array.create(decls_anon_decl.arena(), .{
+            .len = decl_vals.items.len,
+            .elem_type = declaration_ty,
+        }),
+        try Value.Tag.aggregate.create(
+            decls_anon_decl.arena(),
+            try decls_anon_decl.arena().dupe(Value, decl_vals.items),
+        ),
+        0, // default alignment
+    );
+    return try Value.Tag.slice.create(sema.arena, .{
+        .ptr = try Value.Tag.decl_ref.create(sema.arena, new_decl),
+        .len = try Value.Tag.int_u64.create(sema.arena, decl_vals.items.len),
+    });
+}
+
+fn typeInfoNamespaceDecls(
+    sema: *Sema,
+    block: *Block,
+    decls_anon_decl: Allocator,
+    namespace: *Namespace,
+    decl_vals: *std.ArrayList(Value),
+    seen_namespaces: *std.AutoHashMap(*Namespace, void),
+) !void {
+    const gop = try seen_namespaces.getOrPut(namespace);
+    if (gop.found_existing) return;
+    const decls = namespace.decls.keys();
+    for (decls) |decl_index| {
         const decl = sema.mod.declPtr(decl_index);
+        if (decl.kind == .@"usingnamespace") {
+            try sema.mod.ensureDeclAnalyzed(decl_index);
+            var buf: Value.ToTypeBuffer = undefined;
+            const new_ns = decl.val.toType(&buf).getNamespace().?;
+            try sema.typeInfoNamespaceDecls(block, decls_anon_decl, new_ns, decl_vals, seen_namespaces);
+            continue;
+        }
+        if (decl.kind != .named) continue;
         const name_val = v: {
             var anon_decl = try block.startAnonDecl();
             defer anon_decl.deinit();
@@ -16231,37 +16274,21 @@ fn typeInfoDecls(
                 try Value.Tag.bytes.create(anon_decl.arena(), bytes[0 .. bytes.len + 1]),
                 0, // default alignment
             );
-            break :v try Value.Tag.slice.create(decls_anon_decl.arena(), .{
-                .ptr = try Value.Tag.decl_ref.create(decls_anon_decl.arena(), new_decl),
-                .len = try Value.Tag.int_u64.create(decls_anon_decl.arena(), bytes.len),
+            break :v try Value.Tag.slice.create(decls_anon_decl, .{
+                .ptr = try Value.Tag.decl_ref.create(decls_anon_decl, new_decl),
+                .len = try Value.Tag.int_u64.create(decls_anon_decl, bytes.len),
             });
         };
 
-        const fields = try decls_anon_decl.arena().create([2]Value);
+        const fields = try decls_anon_decl.create([2]Value);
         fields.* = .{
             //name: []const u8,
             name_val,
             //is_pub: bool,
             Value.makeBool(decl.is_pub),
         };
-        decls_val.* = try Value.Tag.aggregate.create(decls_anon_decl.arena(), fields);
+        try decl_vals.append(try Value.Tag.aggregate.create(decls_anon_decl, fields));
     }
-
-    const new_decl = try decls_anon_decl.finish(
-        try Type.Tag.array.create(decls_anon_decl.arena(), .{
-            .len = decls_vals.len,
-            .elem_type = declaration_ty,
-        }),
-        try Value.Tag.aggregate.create(
-            decls_anon_decl.arena(),
-            try decls_anon_decl.arena().dupe(Value, decls_vals),
-        ),
-        0, // default alignment
-    );
-    return try Value.Tag.slice.create(sema.arena, .{
-        .ptr = try Value.Tag.decl_ref.create(sema.arena, new_decl),
-        .len = try Value.Tag.int_u64.create(sema.arena, decls_vals.len),
-    });
 }
 
 fn zirTypeof(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {

test/behavior/type_info.zig

@@ -566,3 +566,27 @@ test "value from struct @typeInfo default_value can be loaded at comptime" {
         try expect(@ptrCast(*const u8, a).* == 1);
     }
 }
+
+test "@typeInfo decls and usingnamespace" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
+
+    const A = struct {
+        const x = 5;
+        const y = 34;
+
+        comptime {}
+    };
+    const B = struct {
+        usingnamespace A;
+        const z = 56;
+
+        test {}
+    };
+    const decls = @typeInfo(B).Struct.decls;
+    try expect(decls.len == 3);
+    try expectEqualStrings(decls[0].name, "x");
+    try expectEqualStrings(decls[1].name, "y");
+    try expectEqualStrings(decls[2].name, "z");
+}