diff --git a/ci/azure/pipelines.yml b/ci/azure/pipelines.yml
index b0fbf0fb72..69ce774cff 100644
--- a/ci/azure/pipelines.yml
+++ b/ci/azure/pipelines.yml
@@ -16,7 +16,7 @@ jobs:
     vmImage: 'windows-2019'
   variables:
     TARGET: 'x86_64-windows-gnu'
-    ZIG_LLVM_CLANG_LLD_NAME: 'zig+llvm+lld+clang-${{ variables.TARGET }}-0.10.0-dev.4560+828735ac0'
+    ZIG_LLVM_CLANG_LLD_NAME: 'zig+llvm+lld+clang-${{ variables.TARGET }}-0.11.0-dev.25+499dddb4c'
     ZIG_LLVM_CLANG_LLD_URL: 'https://ziglang.org/deps/${{ variables.ZIG_LLVM_CLANG_LLD_NAME }}.zip'
   steps:
   - pwsh: |
diff --git a/lib/std/meta.zig b/lib/std/meta.zig
index 600a8ab012..e75108e101 100644
--- a/lib/std/meta.zig
+++ b/lib/std/meta.zig
@@ -304,7 +304,7 @@ pub fn Sentinel(comptime T: type, comptime sentinel_val: Elem(T)) type {
                             .Array = .{
                                 .len = array_info.len,
                                 .child = array_info.child,
-                                .sentinel = &sentinel_val,
+                                .sentinel = @ptrCast(?*const anyopaque, &sentinel_val),
                             },
                         }),
                         .is_allowzero = info.is_allowzero,
@@ -322,7 +322,7 @@ pub fn Sentinel(comptime T: type, comptime sentinel_val: Elem(T)) type {
                     .address_space = info.address_space,
                     .child = info.child,
                     .is_allowzero = info.is_allowzero,
-                    .sentinel = &sentinel_val,
+                    .sentinel = @ptrCast(?*const anyopaque, &sentinel_val),
                 },
             }),
             else => {},
@@ -340,7 +340,7 @@ pub fn Sentinel(comptime T: type, comptime sentinel_val: Elem(T)) type {
                                 .address_space = ptr_info.address_space,
                                 .child = ptr_info.child,
                                 .is_allowzero = ptr_info.is_allowzero,
-                                .sentinel = &sentinel_val,
+                                .sentinel = @ptrCast(?*const anyopaque, &sentinel_val),
                             },
                         }),
                     },
diff --git a/lib/std/start_windows_tls.zig b/lib/std/start_windows_tls.zig
index 7c9930fe6b..df25a903a2 100644
--- a/lib/std/start_windows_tls.zig
+++ b/lib/std/start_windows_tls.zig
@@ -42,7 +42,7 @@ export const _tls_used linksection(".rdata$T") = IMAGE_TLS_DIRECTORY{
     .StartAddressOfRawData = &_tls_start,
     .EndAddressOfRawData = &_tls_end,
     .AddressOfIndex = &_tls_index,
-    .AddressOfCallBacks = &__xl_a,
+    .AddressOfCallBacks = @ptrCast(*anyopaque, &__xl_a),
     .SizeOfZeroFill = 0,
     .Characteristics = 0,
 };
diff --git a/lib/std/zig/Ast.zig b/lib/std/zig/Ast.zig
index 62a567387f..5dd0cdd5af 100644
--- a/lib/std/zig/Ast.zig
+++ b/lib/std/zig/Ast.zig
@@ -197,7 +197,7 @@ pub fn renderError(tree: Ast, parse_error: Error, stream: anytype) !void {
             });
         },
         .expected_labelable => {
-            return stream.print("expected 'while', 'for', 'inline', 'suspend', or '{{', found '{s}'", .{
+            return stream.print("expected 'while', 'for', 'inline', or '{{', found '{s}'", .{
                 token_tags[parse_error.token + @boolToInt(parse_error.token_is_prev)].symbol(),
             });
         },
@@ -356,6 +356,12 @@ pub fn renderError(tree: Ast, parse_error: Error, stream: anytype) !void {
         .next_field => {
             return stream.writeAll("field after declarations here");
         },
+        .expected_var_const => {
+            return stream.writeAll("expected 'var' or 'const' before variable declaration");
+        },
+        .wrong_equal_var_decl => {
+            return stream.writeAll("variable initialized with '==' instead of '='");
+        },
 
         .expected_token => {
             const found_tag = token_tags[parse_error.token + @boolToInt(parse_error.token_is_prev)];
@@ -2579,6 +2585,8 @@ pub const Error = struct {
         mismatched_binary_op_whitespace,
         invalid_ampersand_ampersand,
         c_style_container,
+        expected_var_const,
+        wrong_equal_var_decl,
 
         zig_style_container,
         previous_field,
diff --git a/lib/std/zig/parse.zig b/lib/std/zig/parse.zig
index db56cef21e..1be074fc27 100644
--- a/lib/std/zig/parse.zig
+++ b/lib/std/zig/parse.zig
@@ -812,7 +812,18 @@ const Parser = struct {
         const align_node = try p.parseByteAlign();
         const addrspace_node = try p.parseAddrSpace();
         const section_node = try p.parseLinkSection();
-        const init_node: Node.Index = if (p.eatToken(.equal) == null) 0 else try p.expectExpr();
+        const init_node: Node.Index = switch (p.token_tags[p.tok_i]) {
+            .equal_equal => blk: {
+                try p.warn(.wrong_equal_var_decl);
+                p.tok_i += 1;
+                break :blk try p.expectExpr();
+            },
+            .equal => blk: {
+                p.tok_i += 1;
+                break :blk try p.expectExpr();
+            },
+            else => 0,
+        };
         if (section_node == 0 and addrspace_node == 0) {
             if (align_node == 0) {
                 return p.addNode(.{
@@ -1118,7 +1129,18 @@ const Parser = struct {
         if (loop_stmt != 0) return loop_stmt;
 
         if (label_token != 0) {
-            return p.fail(.expected_labelable);
+            const after_colon = p.tok_i;
+            const node = try p.parseTypeExpr();
+            if (node != 0) {
+                const a = try p.parseByteAlign();
+                const b = try p.parseAddrSpace();
+                const c = try p.parseLinkSection();
+                const d = if (p.eatToken(.equal) == null) 0 else try p.expectExpr();
+                if (a != 0 or b != 0 or c != 0 or d != 0) {
+                    return p.failMsg(.{ .tag = .expected_var_const, .token = label_token });
+                }
+            }
+            return p.failMsg(.{ .tag = .expected_labelable, .token = after_colon });
         }
 
         return null_node;
diff --git a/lib/std/zig/parser_test.zig b/lib/std/zig/parser_test.zig
index 4e155df6d8..4ecc0d283d 100644
--- a/lib/std/zig/parser_test.zig
+++ b/lib/std/zig/parser_test.zig
@@ -5145,6 +5145,40 @@ test "zig fmt: make single-line if no trailing comma" {
     );
 }
 
+test "zig fmt: variable initialized with ==" {
+    try testError(
+        \\comptime {
+        \\    var z: u32 == 12 + 1;
+        \\}
+    , &.{.wrong_equal_var_decl});
+}
+
+test "zig fmt: missing const/var before local variable" {
+    try testError(
+        \\comptime {
+        \\    z: u32;
+        \\}
+        \\comptime {
+        \\    z: u32 align(1);
+        \\}
+        \\comptime {
+        \\    z: u32 addrspace(.generic);
+        \\}
+        \\comptime {
+        \\    z: u32 linksection("foo");
+        \\}
+        \\comptime {
+        \\    z: u32 = 1;
+        \\}
+    , &.{
+        .expected_labelable,
+        .expected_var_const,
+        .expected_var_const,
+        .expected_var_const,
+        .expected_var_const,
+    });
+}
+
 test "zig fmt: while continue expr" {
     try testCanonical(
         \\test {
diff --git a/src/AstGen.zig b/src/AstGen.zig
index d71a2fd13d..5006730cad 100644
--- a/src/AstGen.zig
+++ b/src/AstGen.zig
@@ -6500,9 +6500,14 @@ fn switchExpr(
     }
 
     const operand_ri: ResultInfo = .{ .rl = if (any_payload_is_ref) .ref else .none };
+    astgen.advanceSourceCursorToNode(operand_node);
+    const operand_line = astgen.source_line - parent_gz.decl_line;
+    const operand_column = astgen.source_column;
     const raw_operand = try expr(parent_gz, scope, operand_ri, operand_node);
     const cond_tag: Zir.Inst.Tag = if (any_payload_is_ref) .switch_cond_ref else .switch_cond;
     const cond = try parent_gz.addUnNode(cond_tag, raw_operand, operand_node);
+    // Sema expects a dbg_stmt immediately after switch_cond(_ref)
+    try emitDbgStmt(parent_gz, operand_line, operand_column);
     // We need the type of the operand to use as the result location for all the prong items.
     const cond_ty_inst = try parent_gz.addUnNode(.typeof, cond, operand_node);
     const item_ri: ResultInfo = .{ .rl = .{ .ty = cond_ty_inst } };
diff --git a/src/Sema.zig b/src/Sema.zig
index 8bf0649cc2..f3aa861b5c 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -9662,6 +9662,9 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
     const extra = sema.code.extraData(Zir.Inst.SwitchBlock, inst_data.payload_index);
 
     const operand = try sema.resolveInst(extra.data.operand);
+    // AstGen guarantees that the instruction immediately following
+    // switch_cond(_ref) is a dbg_stmt
+    const cond_dbg_node_index = Zir.refToIndex(extra.data.operand).? + 1;
 
     var header_extra_index: usize = extra.end;
 
@@ -10358,6 +10361,7 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
         if (backend_supports_is_named_enum and block.wantSafety() and operand_ty.zigTypeTag() == .Enum and
             (!operand_ty.isNonexhaustiveEnum() or union_originally))
         {
+            try sema.zirDbgStmt(block, cond_dbg_node_index);
             const ok = try block.addUnOp(.is_named_enum_value, operand);
             try sema.addSafetyCheck(block, ok, .corrupt_switch);
         }
@@ -10827,6 +10831,7 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
         if (backend_supports_is_named_enum and special.body.len != 0 and block.wantSafety() and
             operand_ty.zigTypeTag() == .Enum and (!operand_ty.isNonexhaustiveEnum() or union_originally))
         {
+            try sema.zirDbgStmt(&case_block, cond_dbg_node_index);
             const ok = try case_block.addUnOp(.is_named_enum_value, operand);
             try sema.addSafetyCheck(&case_block, ok, .corrupt_switch);
         }
@@ -10850,6 +10855,7 @@ fn zirSwitchBlock(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError
             // We still need a terminator in this block, but we have proven
             // that it is unreachable.
             if (case_block.wantSafety()) {
+                try sema.zirDbgStmt(&case_block, cond_dbg_node_index);
                 _ = try sema.safetyPanic(&case_block, src, .corrupt_switch);
             } else {
                 _ = try case_block.addNoOp(.unreach);
@@ -16620,7 +16626,17 @@ fn zirPtrType(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
     const bitoffset_src: LazySrcLoc = .{ .node_offset_ptr_bitoffset = extra.data.src_node };
     const hostsize_src: LazySrcLoc = .{ .node_offset_ptr_hostsize = extra.data.src_node };
 
-    const unresolved_elem_ty = try sema.resolveType(block, elem_ty_src, extra.data.elem_type);
+    const unresolved_elem_ty = blk: {
+        const air_inst = try sema.resolveInst(extra.data.elem_type);
+        const ty = sema.analyzeAsType(block, elem_ty_src, air_inst) catch |err| {
+            if (err == error.AnalysisFail and sema.err != null and sema.typeOf(air_inst).isSinglePointer()) {
+                try sema.errNote(block, elem_ty_src, sema.err.?, "use '.*' to dereference pointer", .{});
+            }
+            return err;
+        };
+        if (ty.tag() == .generic_poison) return error.GenericPoison;
+        break :blk ty;
+    };
     const target = sema.mod.getTarget();
 
     var extra_i = extra.end;
@@ -18666,6 +18682,13 @@ fn zirFloatToInt(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!
     }
 
     try sema.requireRuntimeBlock(block, inst_data.src(), operand_src);
+    if (dest_ty.intInfo(sema.mod.getTarget()).bits == 0) {
+        if (block.wantSafety()) {
+            const ok = try block.addBinOp(if (block.float_mode == .Optimized) .cmp_eq_optimized else .cmp_eq, operand, try sema.addConstant(operand_ty, Value.zero));
+            try sema.addSafetyCheck(block, ok, .integer_part_out_of_bounds);
+        }
+        return sema.addConstant(dest_ty, Value.zero);
+    }
     const result = try block.addTyOp(if (block.float_mode == .Optimized) .float_to_int_optimized else .float_to_int, dest_ty, operand);
     if (block.wantSafety()) {
         const back = try block.addTyOp(.int_to_float, operand_ty, result);
@@ -18932,6 +18955,9 @@ fn zirPtrCast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
         if (!dest_ty.ptrAllowsZero() and operand_val.isNull()) {
             return sema.fail(block, operand_src, "null pointer casted to type {}", .{dest_ty.fmt(sema.mod)});
         }
+        if (dest_ty.zigTypeTag() == .Optional and sema.typeOf(ptr).zigTypeTag() != .Optional) {
+            return sema.addConstant(dest_ty, try Value.Tag.opt_payload.create(sema.arena, operand_val));
+        }
         return sema.addConstant(aligned_dest_ty, operand_val);
     }
 
@@ -23919,9 +23945,20 @@ fn coerceExtra(
             // cast from ?*T and ?[*]T to ?*anyopaque
             // but don't do it if the source type is a double pointer
             if (dest_ty.isPtrLikeOptional() and dest_ty.elemType2().tag() == .anyopaque and
-                inst_ty.isPtrLikeOptional() and inst_ty.elemType2().zigTypeTag() != .Pointer)
-            {
+                inst_ty.isPtrAtRuntime())
+            anyopaque_check: {
                 if (!sema.checkPtrAttributes(dest_ty, inst_ty, &in_memory_result)) break :optional;
+                const elem_ty = inst_ty.elemType2();
+                if (elem_ty.zigTypeTag() == .Pointer or elem_ty.isPtrLikeOptional()) {
+                    in_memory_result = .{ .double_ptr_to_anyopaque = .{
+                        .actual = inst_ty,
+                        .wanted = dest_ty,
+                    } };
+                    break :optional;
+                }
+                // Let the logic below handle wrapping the optional now that
+                // it has been checked to correctly coerce.
+                if (!inst_ty.isPtrLikeOptional()) break :anyopaque_check;
                 return sema.coerceCompatiblePtrs(block, dest_ty, inst, inst_src);
             }
 
@@ -24044,9 +24081,16 @@ fn coerceExtra(
 
             // cast from *T and [*]T to *anyopaque
             // but don't do it if the source type is a double pointer
-            if (dest_info.pointee_type.tag() == .anyopaque and inst_ty.zigTypeTag() == .Pointer and
-                inst_ty.childType().zigTypeTag() != .Pointer and sema.checkPtrAttributes(dest_ty, inst_ty, &in_memory_result))
-            {
+            if (dest_info.pointee_type.tag() == .anyopaque and inst_ty.zigTypeTag() == .Pointer) {
+                if (!sema.checkPtrAttributes(dest_ty, inst_ty, &in_memory_result)) break :pointer;
+                const elem_ty = inst_ty.elemType2();
+                if (elem_ty.zigTypeTag() == .Pointer or elem_ty.isPtrLikeOptional()) {
+                    in_memory_result = .{ .double_ptr_to_anyopaque = .{
+                        .actual = inst_ty,
+                        .wanted = dest_ty,
+                    } };
+                    break :pointer;
+                }
                 return sema.coerceCompatiblePtrs(block, dest_ty, inst, inst_src);
             }
 
@@ -24528,6 +24572,7 @@ const InMemoryCoercionResult = union(enum) {
     ptr_allowzero: Pair,
     ptr_bit_range: BitRange,
     ptr_alignment: IntPair,
+    double_ptr_to_anyopaque: Pair,
 
     const Pair = struct {
         actual: Type,
@@ -24820,6 +24865,12 @@ const InMemoryCoercionResult = union(enum) {
                 });
                 break;
             },
+            .double_ptr_to_anyopaque => |pair| {
+                try sema.errNote(block, src, msg, "cannot implicitly cast double pointer '{}' to anyopaque pointer '{}'", .{
+                    pair.actual.fmt(sema.mod), pair.wanted.fmt(sema.mod),
+                });
+                break;
+            },
         };
     }
 };
diff --git a/src/type.zig b/src/type.zig
index c4276185ca..a12733cbcb 100644
--- a/src/type.zig
+++ b/src/type.zig
@@ -3944,10 +3944,7 @@ pub const Type = extern union {
             .optional => {
                 var buf: Payload.ElemType = undefined;
                 const child_type = self.optionalChild(&buf);
-                // optionals of zero sized pointers behave like bools
-                if (!child_type.hasRuntimeBits()) return false;
                 if (child_type.zigTypeTag() != .Pointer) return false;
-
                 const info = child_type.ptrInfo().data;
                 switch (info.size) {
                     .Slice, .C => return false,
diff --git a/test/behavior/cast.zig b/test/behavior/cast.zig
index 573f3a7ac2..07d45ad3dc 100644
--- a/test/behavior/cast.zig
+++ b/test/behavior/cast.zig
@@ -1411,3 +1411,11 @@ test "peer type resolution of const and non-const pointer to array" {
     try std.testing.expect(@TypeOf(a, b) == *const [1024]u8);
     try std.testing.expect(a == b);
 }
+
+test "floatToInt to zero-bit int" {
+    if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
+    if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
+
+    var a: f32 = 0.0;
+    comptime try std.testing.expect(@floatToInt(u0, a) == 0);
+}
diff --git a/test/cases/compile_errors/dont_implicit_cast_double_pointer_to_anyopaque.zig b/test/cases/compile_errors/dont_implicit_cast_double_pointer_to_anyopaque.zig
deleted file mode 100644
index 44ae18ae8a..0000000000
--- a/test/cases/compile_errors/dont_implicit_cast_double_pointer_to_anyopaque.zig
+++ /dev/null
@@ -1,14 +0,0 @@
-export fn entry() void {
-    var a: u32 = 1;
-    var ptr: *align(@alignOf(u32)) anyopaque = &a;
-    var b: *u32 = @ptrCast(*u32, ptr);
-    var ptr2: *anyopaque = &b;
-    _ = ptr2;
-}
-
-// error
-// backend=stage2
-// target=native
-//
-// :5:28: error: expected type '*anyopaque', found '**u32'
-// :5:28: note: pointer type child '*u32' cannot cast into pointer type child 'anyopaque'
diff --git a/test/cases/compile_errors/double_pointer_to_anyopaque_pointer.zig b/test/cases/compile_errors/double_pointer_to_anyopaque_pointer.zig
new file mode 100644
index 0000000000..6aa9618dbd
--- /dev/null
+++ b/test/cases/compile_errors/double_pointer_to_anyopaque_pointer.zig
@@ -0,0 +1,28 @@
+pub export fn entry1() void {
+    const x: usize = 5;
+
+    const ptr: *const anyopaque = &(&x);
+    _ = ptr;
+}
+pub export fn entry2() void {
+    var val: [*:0]u8 = undefined;
+    func(&val);
+}
+fn func(_: ?*anyopaque) void {}
+pub export fn entry3() void {
+    var x: *?*usize = undefined;
+
+    const ptr: *const anyopaque = x;
+    _ = ptr;
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :4:35: error: expected type '*const anyopaque', found '*const *const usize'
+// :4:35: note: cannot implicitly cast double pointer '*const *const usize' to anyopaque pointer '*const anyopaque'
+// :9:10: error: expected type '?*anyopaque', found '*[*:0]u8'
+// :9:10: note: cannot implicitly cast double pointer '*[*:0]u8' to anyopaque pointer '?*anyopaque'
+// :15:35: error: expected type '*const anyopaque', found '*?*usize'
+// :15:35: note: cannot implicitly cast double pointer '*?*usize' to anyopaque pointer '*const anyopaque'
diff --git a/test/cases/compile_errors/incorrect_pointer_dereference_syntax.zig b/test/cases/compile_errors/incorrect_pointer_dereference_syntax.zig
new file mode 100644
index 0000000000..33b5d1f3b6
--- /dev/null
+++ b/test/cases/compile_errors/incorrect_pointer_dereference_syntax.zig
@@ -0,0 +1,11 @@
+pub export fn entry() void {
+    var a: *u32 = undefined;
+    _ = *a;
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :3:10: error: expected type 'type', found '*u32'
+// :3:10: note: use '.*' to dereference pointer