From fd6b79e67f0cf91a72c121fc6fd484a03f487506 Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Fri, 6 Jan 2023 18:21:21 +0200
Subject: [PATCH 1/7] Sema: restore status on layout resolution failure

`resolveTypeFields` and `resolveTypeFully` already do this.

Closes #14059
---
 src/Sema.zig | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/Sema.zig b/src/Sema.zig
index 95de857616..6fa2f92dd7 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -29847,6 +29847,11 @@ fn resolveStructLayout(sema: *Sema, ty: Type) CompileError!void {
             },
             .have_layout, .fully_resolved_wip, .fully_resolved => return,
         }
+        const prev_status = struct_obj.status;
+        errdefer if (struct_obj.status == .layout_wip) {
+            struct_obj.status = prev_status;
+        };
+
         struct_obj.status = .layout_wip;
         for (struct_obj.fields.values()) |field, i| {
             sema.resolveTypeLayout(field.ty) catch |err| switch (err) {
@@ -30026,6 +30031,11 @@ fn resolveUnionLayout(sema: *Sema, ty: Type) CompileError!void {
         },
         .have_layout, .fully_resolved_wip, .fully_resolved => return,
     }
+    const prev_status = union_obj.status;
+    errdefer if (union_obj.status == .layout_wip) {
+        union_obj.status = prev_status;
+    };
+
     union_obj.status = .layout_wip;
     for (union_obj.fields.values()) |field, i| {
         sema.resolveTypeLayout(field.ty) catch |err| switch (err) {

From 83673a8b5f508376c81deaa4b01815474873eb69 Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Fri, 6 Jan 2023 19:03:40 +0200
Subject: [PATCH 2/7] fix errdefers in functions that can't return errors

This was broken by 58caed1c71179f48c4e7bffadef0392fa8381e72

Closes #14053
---
 src/AstGen.zig          |  3 ++-
 src/Sema.zig            | 14 +++++++++++++-
 src/Zir.zig             |  6 ++++++
 src/print_zir.zig       |  1 +
 test/behavior/defer.zig | 11 +++++++++++
 5 files changed, 33 insertions(+), 2 deletions(-)

diff --git a/src/AstGen.zig b/src/AstGen.zig
index 7331ab6410..1d2244a5b5 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -2463,6 +2463,7 @@ fn addEnsureResult(gz: *GenZir, maybe_unused_result: Zir.Inst.Ref, statement: As
             .is_non_null_ptr,
             .is_non_err,
             .is_non_err_ptr,
+            .ret_is_non_err,
             .mod_rem,
             .mul,
             .mulwrap,
@@ -7012,7 +7013,7 @@ fn ret(gz: *GenZir, scope: *Scope, node: Ast.Node.Index) InnerError!Zir.Inst.Ref
 
             // Emit conditional branch for generating errdefers.
             const result = if (ri.rl == .ptr) try gz.addUnNode(.load, ri.rl.ptr.inst, node) else operand;
-            const is_non_err = try gz.addUnNode(.is_non_err, result, node);
+            const is_non_err = try gz.addUnNode(.ret_is_non_err, result, node);
             const condbr = try gz.addCondBr(.condbr, node);
 
             var then_scope = gz.makeSubBlock(scope);
diff --git a/src/Sema.zig b/src/Sema.zig
index 6fa2f92dd7..ec698f7a3b 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -953,6 +953,7 @@ fn analyzeBodyInner(
             .int_type                     => try sema.zirIntType(block, inst),
             .is_non_err                   => try sema.zirIsNonErr(block, inst),
             .is_non_err_ptr               => try sema.zirIsNonErrPtr(block, inst),
+            .ret_is_non_err               => try sema.zirRetIsNonErr(block, inst),
             .is_non_null                  => try sema.zirIsNonNull(block, inst),
             .is_non_null_ptr              => try sema.zirIsNonNullPtr(block, inst),
             .merge_error_sets             => try sema.zirMergeErrorSets(block, inst),
@@ -10288,6 +10289,7 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
                         .ret_err_value_code,
                         .restore_err_ret_index,
                         .is_non_err,
+                        .ret_is_non_err,
                         .condbr,
                         => {},
                         else => break,
@@ -16577,7 +16579,7 @@ fn zirIsNonErr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Ai
     const src = inst_data.src();
     const operand = try sema.resolveInst(inst_data.operand);
     try sema.checkErrorType(block, src, sema.typeOf(operand));
-    return sema.analyzeIsNonErr(block, inst_data.src(), operand);
+    return sema.analyzeIsNonErr(block, src, operand);
 }
 
 fn zirIsNonErrPtr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
@@ -16592,6 +16594,16 @@ fn zirIsNonErrPtr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
     return sema.analyzeIsNonErr(block, src, loaded);
 }
 
+fn zirRetIsNonErr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.Inst.Ref {
+    const tracy = trace(@src());
+    defer tracy.end();
+
+    const inst_data = sema.code.instructions.items(.data)[inst].un_node;
+    const src = inst_data.src();
+    const operand = try sema.resolveInst(inst_data.operand);
+    return sema.analyzeIsNonErr(block, src, operand);
+}
+
 fn zirCondbr(
     sema: *Sema,
     parent_block: *Block,
diff --git a/src/Zir.zig b/src/Zir.zig
index 3f2e935050..94e6a9a11a 100644
--- a/src/Zir.zig
+++ b/src/Zir.zig
@@ -481,6 +481,9 @@ pub const Inst = struct {
         /// Return a boolean false if dereferenced pointer is an error
         /// Uses the `un_node` field.
         is_non_err_ptr,
+        /// Same as `is_non_er` but doesn't validate that the type can be an error.
+        /// Uses the `un_node` field.
+        ret_is_non_err,
         /// A labeled block of code that loops forever. At the end of the body will have either
         /// a `repeat` instruction or a `repeat_inline` instruction.
         /// Uses the `pl_node` field. The AST node is either a for loop or while loop.
@@ -1083,6 +1086,7 @@ pub const Inst = struct {
                 .is_non_null_ptr,
                 .is_non_err,
                 .is_non_err_ptr,
+                .ret_is_non_err,
                 .mod_rem,
                 .mul,
                 .mulwrap,
@@ -1386,6 +1390,7 @@ pub const Inst = struct {
                 .is_non_null_ptr,
                 .is_non_err,
                 .is_non_err_ptr,
+                .ret_is_non_err,
                 .mod_rem,
                 .mul,
                 .mulwrap,
@@ -1640,6 +1645,7 @@ pub const Inst = struct {
                 .is_non_null_ptr = .un_node,
                 .is_non_err = .un_node,
                 .is_non_err_ptr = .un_node,
+                .ret_is_non_err = .un_node,
                 .loop = .pl_node,
                 .repeat = .node,
                 .repeat_inline = .node,
diff --git a/src/print_zir.zig b/src/print_zir.zig
index 49c97a5bc7..6e8923bed9 100644
--- a/src/print_zir.zig
+++ b/src/print_zir.zig
@@ -179,6 +179,7 @@ const Writer = struct {
             .is_non_null_ptr,
             .is_non_err,
             .is_non_err_ptr,
+            .ret_is_non_err,
             .typeof,
             .struct_init_empty,
             .type_info,
diff --git a/test/behavior/defer.zig b/test/behavior/defer.zig
index 9b83290a0a..32f63b1a46 100644
--- a/test/behavior/defer.zig
+++ b/test/behavior/defer.zig
@@ -148,3 +148,14 @@ test "simple else prong doesn't emit an error for unreachable else prong" {
     };
     try expect(a == 1);
 }
+
+test "errdefer used in function that doesn't return an error" {
+    const S = struct {
+        fn foo() u8 {
+            var a: u8 = 5;
+            errdefer a += 1;
+            return a;
+        }
+    };
+    try expect(S.foo() == 5);
+}

From ad259736e2200e93400e4f09916551ae65ca56ad Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Mon, 9 Jan 2023 17:44:41 +0200
Subject: [PATCH 3/7] Value: implement more pointer eql cases

Closes #14234
---
 src/value.zig | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/src/value.zig b/src/value.zig
index 45b2bfd341..5d38bcb7a9 100644
--- a/src/value.zig
+++ b/src/value.zig
@@ -2193,8 +2193,16 @@ pub const Value = extern union {
                 const payload_ty = ty.errorUnionPayload();
                 return eqlAdvanced(a_payload, payload_ty, b_payload, payload_ty, mod, opt_sema);
             },
-            .eu_payload_ptr => @panic("TODO: Implement more pointer eql cases"),
-            .opt_payload_ptr => @panic("TODO: Implement more pointer eql cases"),
+            .eu_payload_ptr => {
+                const a_payload = a.castTag(.eu_payload_ptr).?.data;
+                const b_payload = b.castTag(.eu_payload_ptr).?.data;
+                return eqlAdvanced(a_payload.container_ptr, ty, b_payload.container_ptr, ty, mod, opt_sema);
+            },
+            .opt_payload_ptr => {
+                const a_payload = a.castTag(.opt_payload_ptr).?.data;
+                const b_payload = b.castTag(.opt_payload_ptr).?.data;
+                return eqlAdvanced(a_payload.container_ptr, ty, b_payload.container_ptr, ty, mod, opt_sema);
+            },
             .function => {
                 const a_payload = a.castTag(.function).?.data;
                 const b_payload = b.castTag(.function).?.data;

From 8b1780d9396aa7bd919f2ec5e003f981bbce07d5 Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Tue, 10 Jan 2023 14:04:38 +0200
Subject: [PATCH 4/7] Sema: fix condition for omitting comptime arg from
 function type

Closes #14164
---
 src/Sema.zig                                  |  2 +-
 ...d_generic_function_param_type_mismatch.zig | 24 +++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 test/cases/compile_errors/nested_generic_function_param_type_mismatch.zig

diff --git a/src/Sema.zig b/src/Sema.zig
index ec698f7a3b..8263468fbf 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -9005,7 +9005,7 @@ fn zirParam(
         else => |e| return e,
     } or comptime_syntax;
     if (sema.inst_map.get(inst)) |arg| {
-        if (is_comptime) {
+        if (is_comptime and sema.preallocated_new_func != null) {
             // We have a comptime value for this parameter so it should be elided from the
             // function type of the function instruction in this block.
             const coerced_arg = try sema.coerce(block, param_ty, arg, src);
diff --git a/test/cases/compile_errors/nested_generic_function_param_type_mismatch.zig b/test/cases/compile_errors/nested_generic_function_param_type_mismatch.zig
new file mode 100644
index 0000000000..2c05a1dd4a
--- /dev/null
+++ b/test/cases/compile_errors/nested_generic_function_param_type_mismatch.zig
@@ -0,0 +1,24 @@
+pub fn sort(
+    comptime T: type,
+    items: []T,
+    context: anytype,
+    lessThan: *const fn (context: @TypeOf(context), lhs: T, rhs: T) u32,
+) void {
+    _ = items;
+    _ = lessThan;
+}
+fn foo(_: void, _: u8, _: u8) u32 {
+    return 0;
+}
+pub export fn entry() void {
+    var items = [_]u8{ 3, 5, 7, 2, 6, 9, 4 };
+    sort(u8, &items, void, foo);
+}
+
+// error
+// backend=llvm
+// target=native
+//
+// :15:28: error: expected type '*const fn(comptime type, u8, u8) u32', found '*const fn(void, u8, u8) u32'
+// :15:28: note: pointer type child 'fn(void, u8, u8) u32' cannot cast into pointer type child 'fn(comptime type, u8, u8) u32'
+// :15:28: note: non-generic function cannot cast into a generic function

From e2adf3b61a32eae2182bcb94981a0b3706040f9a Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Tue, 10 Jan 2023 15:04:14 +0200
Subject: [PATCH 5/7] parser: add helpful note for missing const/var before
 container level decl

Closes #13888
---
 lib/std/zig/Ast.zig         |  4 ++++
 lib/std/zig/parse.zig       |  7 +++++++
 lib/std/zig/parser_test.zig | 12 ++++++++++++
 3 files changed, 23 insertions(+)

diff --git a/lib/std/zig/Ast.zig b/lib/std/zig/Ast.zig
index 0573622d6f..f312093aa3 100644
--- a/lib/std/zig/Ast.zig
+++ b/lib/std/zig/Ast.zig
@@ -362,6 +362,9 @@ pub fn renderError(tree: Ast, parse_error: Error, stream: anytype) !void {
         .wrong_equal_var_decl => {
             return stream.writeAll("variable initialized with '==' instead of '='");
         },
+        .var_const_decl => {
+            return stream.writeAll("use 'var' or 'const' to declare variable");
+        },
 
         .expected_token => {
             const found_tag = token_tags[parse_error.token + @boolToInt(parse_error.token_is_prev)];
@@ -2743,6 +2746,7 @@ pub const Error = struct {
         c_style_container,
         expected_var_const,
         wrong_equal_var_decl,
+        var_const_decl,
 
         zig_style_container,
         previous_field,
diff --git a/lib/std/zig/parse.zig b/lib/std/zig/parse.zig
index 3bb27975db..fdb122b19d 100644
--- a/lib/std/zig/parse.zig
+++ b/lib/std/zig/parse.zig
@@ -471,6 +471,13 @@ const Parser = struct {
                     // There is not allowed to be a decl after a field with no comma.
                     // Report error but recover parser.
                     try p.warn(.expected_comma_after_field);
+                    if (p.token_tags[p.tok_i] == .semicolon and p.token_tags[identifier] == .identifier) {
+                        try p.warnMsg(.{
+                            .tag = .var_const_decl,
+                            .is_note = true,
+                            .token = identifier,
+                        });
+                    }
                     p.findNextContainerMember();
                     continue;
                 },
diff --git a/lib/std/zig/parser_test.zig b/lib/std/zig/parser_test.zig
index 1b8a240642..42eb1abdde 100644
--- a/lib/std/zig/parser_test.zig
+++ b/lib/std/zig/parser_test.zig
@@ -5238,6 +5238,18 @@ test "zig fmt: missing const/var before local variable" {
     });
 }
 
+test "zig fmt: missing const/var before local variable" {
+    try testError(
+        \\std = foo,
+        \\std = foo;
+        \\*u32 = foo;
+    , &.{
+        .expected_comma_after_field,
+        .var_const_decl,
+        .expected_comma_after_field,
+    });
+}
+
 test "zig fmt: while continue expr" {
     try testCanonical(
         \\test {

From 1658e4893d749c7d1ed378cd34b6cbe1a132c0e9 Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Tue, 10 Jan 2023 15:07:48 +0200
Subject: [PATCH 6/7] AstGen: add note pointing to tuple field

Closes #14188
---
 src/AstGen.zig                                  | 17 ++++++++++++++++-
 .../cases/compile_errors/tuple_declarations.zig |  1 +
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/AstGen.zig b/src/AstGen.zig
index 1d2244a5b5..894acdd8f2 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -4487,9 +4487,24 @@ fn structDeclInner(
             .container_field_align,
             .container_field,
             .@"comptime",
+            .test_decl,
             => continue,
             else => {
-                return astgen.failNode(member_node, "tuple declarations cannot contain declarations", .{});
+                const tuple_member = for (container_decl.ast.members) |maybe_tuple| switch (node_tags[maybe_tuple]) {
+                    .container_field_init,
+                    .container_field_align,
+                    .container_field,
+                    => break maybe_tuple,
+                    else => {},
+                } else unreachable;
+                return astgen.failNodeNotes(
+                    member_node,
+                    "tuple declarations cannot contain declarations",
+                    .{},
+                    &[_]u32{
+                        try astgen.errNoteNode(tuple_member, "tuple field here", .{}),
+                    },
+                );
             },
         }
     };
diff --git a/test/cases/compile_errors/tuple_declarations.zig b/test/cases/compile_errors/tuple_declarations.zig
index ec72561816..9a181e9769 100644
--- a/test/cases/compile_errors/tuple_declarations.zig
+++ b/test/cases/compile_errors/tuple_declarations.zig
@@ -23,3 +23,4 @@ const T = struct {
 // :5:5: error: union field missing name
 // :8:5: error: tuple field has a name
 // :15:5: error: tuple declarations cannot contain declarations
+// :12:5: note: tuple field here

From d8128c272a087bbfc0b33a786c18267f49cd4982 Mon Sep 17 00:00:00 2001
From: Veikka Tuominen <git@vexu.eu>
Date: Tue, 10 Jan 2023 21:54:58 +0200
Subject: [PATCH 7/7] Sema: fix typeInfo decls with usingnamespace

Closes #12403
---
 src/Module.zig              | 31 ++++++++++-----
 src/Sema.zig                | 77 +++++++++++++++++++++++++------------
 test/behavior/type_info.zig | 24 ++++++++++++
 3 files changed, 98 insertions(+), 34 deletions(-)

diff --git a/src/Module.zig b/src/Module.zig
index 4fcd2e7ba6..558ed498ca 100644
--- a/src/Module.zig
+++ b/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),
@@ -4964,26 +4972,31 @@ 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: {
@@ -4991,6 +5004,7 @@ fn scanDecl(iter: *ScanDeclIter, decl_sub_index: usize, flags: u4) Allocator.Err
             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);
@@ -4998,8 +5012,7 @@ fn scanDecl(iter: *ScanDeclIter, decl_sub_index: usize, flags: u4) Allocator.Err
         },
     };
     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;
diff --git a/src/Sema.zig b/src/Sema.zig
index 8263468fbf..3db5eb5ba1 100644
--- a/src/Sema.zig
+++ b/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 {
diff --git a/test/behavior/type_info.zig b/test/behavior/type_info.zig
index 0fb17519e6..ef8c89bd23 100644
--- a/test/behavior/type_info.zig
+++ b/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");
+}