Commit 21f344b3b9

Andrew Kelley <andrew@ziglang.org>
2019-11-18 05:06:28
add null terminated pointers and arrays to self-hosted
as well as `@typeInfo` and `@Type`
1 parent 1aa978f
lib/std/zig/ast.zig
@@ -137,6 +137,7 @@ pub const Error = union(enum) {
     ExpectedCallOrFnProto: ExpectedCallOrFnProto,
     ExpectedSliceOrRBracket: ExpectedSliceOrRBracket,
     ExtraAlignQualifier: ExtraAlignQualifier,
+    ExtraNullQualifier: ExtraNullQualifier,
     ExtraConstQualifier: ExtraConstQualifier,
     ExtraVolatileQualifier: ExtraVolatileQualifier,
     ExtraAllowZeroQualifier: ExtraAllowZeroQualifier,
@@ -184,6 +185,7 @@ pub const Error = union(enum) {
             .ExpectedCallOrFnProto => |*x| return x.render(tokens, stream),
             .ExpectedSliceOrRBracket => |*x| return x.render(tokens, stream),
             .ExtraAlignQualifier => |*x| return x.render(tokens, stream),
+            .ExtraNullQualifier => |*x| return x.render(tokens, stream),
             .ExtraConstQualifier => |*x| return x.render(tokens, stream),
             .ExtraVolatileQualifier => |*x| return x.render(tokens, stream),
             .ExtraAllowZeroQualifier => |*x| return x.render(tokens, stream),
@@ -233,6 +235,7 @@ pub const Error = union(enum) {
             .ExpectedCallOrFnProto => |x| return x.node.firstToken(),
             .ExpectedSliceOrRBracket => |x| return x.token,
             .ExtraAlignQualifier => |x| return x.token,
+            .ExtraNullQualifier => |x| return x.token,
             .ExtraConstQualifier => |x| return x.token,
             .ExtraVolatileQualifier => |x| return x.token,
             .ExtraAllowZeroQualifier => |x| return x.token,
@@ -293,6 +296,7 @@ pub const Error = union(enum) {
     pub const ExpectedPubItem = SimpleError("Expected function or variable declaration after pub");
     pub const UnattachedDocComment = SimpleError("Unattached documentation comment");
     pub const ExtraAlignQualifier = SimpleError("Extra align qualifier");
+    pub const ExtraNullQualifier = SimpleError("Extra null qualifier");
     pub const ExtraConstQualifier = SimpleError("Extra const qualifier");
     pub const ExtraVolatileQualifier = SimpleError("Extra volatile qualifier");
     pub const ExtraAllowZeroQualifier = SimpleError("Extra allowzero qualifier");
@@ -1538,7 +1542,7 @@ pub const Node = struct {
 
         pub const Op = union(enum) {
             AddressOf,
-            ArrayType: *Node,
+            ArrayType: ArrayInfo,
             Await,
             BitNot,
             BoolNot,
@@ -1552,11 +1556,17 @@ pub const Node = struct {
             Try,
         };
 
+        pub const ArrayInfo = struct {
+            len_expr: *Node,
+            null_token: ?TokenIndex,
+        };
+
         pub const PtrInfo = struct {
             allowzero_token: ?TokenIndex,
             align_info: ?Align,
             const_token: ?TokenIndex,
             volatile_token: ?TokenIndex,
+            null_token: ?TokenIndex,
 
             pub const Align = struct {
                 node: *Node,
@@ -1588,8 +1598,8 @@ pub const Node = struct {
                     }
                 },
 
-                Op.ArrayType => |size_expr| {
-                    if (i < 1) return size_expr;
+                Op.ArrayType => |array_info| {
+                    if (i < 1) return array_info.len_expr;
                     i -= 1;
                 },
 
lib/std/zig/parse.zig
@@ -1085,7 +1085,7 @@ fn parseInitList(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node.Suf
     const node = try arena.create(Node.SuffixOp);
     node.* = Node.SuffixOp{
         .base = Node{ .id = .SuffixOp },
-        .lhs = .{.node = undefined}, // set by caller
+        .lhs = .{ .node = undefined }, // set by caller
         .op = op,
         .rtoken = try expectToken(it, tree, .RBrace),
     };
@@ -1138,7 +1138,7 @@ fn parseSuffixExpr(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node {
 
         while (try parseSuffixOp(arena, it, tree)) |node| {
             switch (node.id) {
-                .SuffixOp => node.cast(Node.SuffixOp).?.lhs = .{.node = res},
+                .SuffixOp => node.cast(Node.SuffixOp).?.lhs = .{ .node = res },
                 .InfixOp => node.cast(Node.InfixOp).?.lhs = res,
                 else => unreachable,
             }
@@ -1154,7 +1154,7 @@ fn parseSuffixExpr(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node {
         const node = try arena.create(Node.SuffixOp);
         node.* = Node.SuffixOp{
             .base = Node{ .id = .SuffixOp },
-            .lhs = .{.node = res},
+            .lhs = .{ .node = res },
             .op = Node.SuffixOp.Op{
                 .Call = Node.SuffixOp.Op.Call{
                     .params = params.list,
@@ -1171,7 +1171,7 @@ fn parseSuffixExpr(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node {
         while (true) {
             if (try parseSuffixOp(arena, it, tree)) |node| {
                 switch (node.id) {
-                    .SuffixOp => node.cast(Node.SuffixOp).?.lhs = .{.node = res},
+                    .SuffixOp => node.cast(Node.SuffixOp).?.lhs = .{ .node = res },
                     .InfixOp => node.cast(Node.InfixOp).?.lhs = res,
                     else => unreachable,
                 }
@@ -1182,7 +1182,7 @@ fn parseSuffixExpr(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node {
                 const call = try arena.create(Node.SuffixOp);
                 call.* = Node.SuffixOp{
                     .base = Node{ .id = .SuffixOp },
-                    .lhs = .{.node = res},
+                    .lhs = .{ .node = res },
                     .op = Node.SuffixOp.Op{
                         .Call = Node.SuffixOp.Op.Call{
                             .params = params.list,
@@ -1531,7 +1531,7 @@ fn parseAnonLiteral(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node
 
     // anon container literal
     if (try parseInitList(arena, it, tree)) |node| {
-        node.lhs = .{.dot = dot};
+        node.lhs = .{ .dot = dot };
         return &node.base;
     }
 
@@ -2252,6 +2252,16 @@ fn parsePrefixTypeOp(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node
             .SliceType => |*slice_type| {
                 // Collect pointer qualifiers in any order, but disallow duplicates
                 while (true) {
+                    if (eatToken(it, .Keyword_null)) |null_token| {
+                        if (slice_type.null_token != null) {
+                            try tree.errors.push(AstError{
+                                .ExtraNullQualifier = AstError.ExtraNullQualifier{ .token = it.index },
+                            });
+                            return error.ParseError;
+                        }
+                        slice_type.null_token = null_token;
+                        continue;
+                    }
                     if (try parseByteAlign(arena, it, tree)) |align_expr| {
                         if (slice_type.align_info != null) {
                             try tree.errors.push(AstError{
@@ -2313,6 +2323,10 @@ fn parsePrefixTypeOp(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node
             &prefix_op.op.PtrType;
 
         while (true) {
+            if (eatToken(it, .Keyword_null)) |null_token| {
+                ptr_info.null_token = null_token;
+                continue;
+            }
             if (eatToken(it, .Keyword_align)) |align_token| {
                 const lparen = try expectToken(it, tree, .LParen);
                 const expr_node = try expectNode(arena, it, tree, parseExpr, AstError{
@@ -2460,9 +2474,15 @@ fn parseArrayTypeStart(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*No
     const lbracket = eatToken(it, .LBracket) orelse return null;
     const expr = try parseExpr(arena, it, tree);
     const rbracket = try expectToken(it, tree, .RBracket);
+    const null_token = eatToken(it, .Keyword_null);
 
-    const op = if (expr) |element_type|
-        Node.PrefixOp.Op{ .ArrayType = element_type }
+    const op = if (expr) |len_expr|
+        Node.PrefixOp.Op{
+            .ArrayType = .{
+                .len_expr = len_expr,
+                .null_token = null_token,
+            },
+        }
     else
         Node.PrefixOp.Op{
             .SliceType = Node.PrefixOp.PtrInfo{
@@ -2470,6 +2490,7 @@ fn parseArrayTypeStart(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*No
                 .align_info = null,
                 .const_token = null,
                 .volatile_token = null,
+                .null_token = null,
             },
         };
 
@@ -2505,6 +2526,7 @@ fn parsePtrTypeStart(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node
                 .align_info = null,
                 .const_token = null,
                 .volatile_token = null,
+                .null_token = null,
             },
         },
         .rhs = undefined, // set by caller
@@ -2522,6 +2544,7 @@ fn parsePtrTypeStart(arena: *Allocator, it: *TokenIterator, tree: *Tree) !?*Node
                     .align_info = null,
                     .const_token = null,
                     .volatile_token = null,
+                    .null_token = null,
                 },
             },
             .rhs = undefined, // set by caller
lib/std/zig/parser_test.zig
@@ -1552,6 +1552,7 @@ test "zig fmt: pointer attributes" {
         \\extern fn f2(s: **align(1) *const *volatile u8) c_int;
         \\extern fn f3(s: *align(1) const *align(1) volatile *const volatile u8) c_int;
         \\extern fn f4(s: *align(1) const volatile u8) c_int;
+        \\extern fn f5(s: [*]null align(1) const volatile u8) c_int;
         \\
     );
 }
@@ -1562,6 +1563,7 @@ test "zig fmt: slice attributes" {
         \\extern fn f2(s: **align(1) *const *volatile u8) c_int;
         \\extern fn f3(s: *align(1) const *align(1) volatile *const volatile u8) c_int;
         \\extern fn f4(s: *align(1) const volatile u8) c_int;
+        \\extern fn f5(s: [*]null align(1) const volatile u8) c_int;
         \\
     );
 }
@@ -1889,6 +1891,7 @@ test "zig fmt: arrays" {
         \\        2,
         \\    };
         \\    const a: [0]u8 = []u8{};
+        \\    const x: [4]null u8 = undefined;
         \\}
         \\
     );
lib/std/zig/render.zig
@@ -423,6 +423,9 @@ fn renderExpression(
                         else => @as(usize, 0),
                     };
                     try renderTokenOffset(tree, stream, prefix_op_node.op_token, indent, start_col, Space.None, star_offset); // *
+                    if (ptr_info.null_token) |null_token| {
+                        try renderToken(tree, stream, null_token, indent, start_col, Space.Space); // null
+                    }
                     if (ptr_info.allowzero_token) |allowzero_token| {
                         try renderToken(tree, stream, allowzero_token, indent, start_col, Space.Space); // allowzero
                     }
@@ -499,9 +502,9 @@ fn renderExpression(
                     }
                 },
 
-                ast.Node.PrefixOp.Op.ArrayType => |array_index| {
+                ast.Node.PrefixOp.Op.ArrayType => |array_info| {
                     const lbracket = prefix_op_node.op_token;
-                    const rbracket = tree.nextToken(array_index.lastToken());
+                    const rbracket = tree.nextToken(array_info.len_expr.lastToken());
 
                     try renderToken(tree, stream, lbracket, indent, start_col, Space.None); // [
 
@@ -509,7 +512,7 @@ fn renderExpression(
                     const ends_with_comment = tree.tokens.at(rbracket - 1).id == .LineComment;
                     const new_indent = if (ends_with_comment) indent + indent_delta else indent;
                     const new_space = if (ends_with_comment) Space.Newline else Space.None;
-                    try renderExpression(allocator, stream, tree, new_indent, start_col, array_index, new_space);
+                    try renderExpression(allocator, stream, tree, new_indent, start_col, array_info.len_expr, new_space);
                     if (starts_with_comment) {
                         try stream.writeByte('\n');
                     }
@@ -517,6 +520,9 @@ fn renderExpression(
                         try stream.writeByteNTimes(' ', indent);
                     }
                     try renderToken(tree, stream, rbracket, indent, start_col, Space.None); // ]
+                    if (array_info.null_token) |null_token| {
+                        try renderToken(tree, stream, null_token, indent, start_col, Space.Space); // null
+                    }
                 },
                 ast.Node.PrefixOp.Op.BitNot,
                 ast.Node.PrefixOp.Op.BoolNot,
lib/std/builtin.zig
@@ -161,6 +161,7 @@ pub const TypeInfo = union(enum) {
     pub const Array = struct {
         len: comptime_int,
         child: type,
+        is_null_terminated: bool,
     };
 
     /// This data structure is used by the Zig language code generation and
src/all_types.hpp
@@ -358,6 +358,7 @@ struct LazyValueSliceType {
     bool is_const;
     bool is_volatile;
     bool is_allowzero;
+    bool is_null_terminated;
 };
 
 struct LazyValuePtrType {
@@ -1234,6 +1235,7 @@ struct ZigTypeFloat {
 struct ZigTypeArray {
     ZigType *child_type;
     uint64_t len;
+    bool is_null_terminated;
 };
 
 struct TypeStructField {
@@ -1775,6 +1777,7 @@ struct TypeId {
         struct {
             ZigType *child_type;
             uint64_t size;
+            bool is_null_terminated;
         } array;
         struct {
             bool is_signed;
@@ -2986,6 +2989,7 @@ struct IrInstructionArrayType {
 
     IrInstruction *size;
     IrInstruction *child_type;
+    bool is_null_terminated;
 };
 
 struct IrInstructionPtrType {
@@ -3015,6 +3019,7 @@ struct IrInstructionSliceType {
     bool is_const;
     bool is_volatile;
     bool is_allow_zero;
+    bool is_null_terminated;
 };
 
 struct IrInstructionGlobalAsm {
src/analyze.cpp
@@ -752,11 +752,12 @@ ZigType *get_error_union_type(CodeGen *g, ZigType *err_set_type, ZigType *payloa
     return entry;
 }
 
-ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size) {
+ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size, bool is_null_terminated) {
     TypeId type_id = {};
     type_id.id = ZigTypeIdArray;
     type_id.data.array.child_type = child_type;
     type_id.data.array.size = array_size;
+    type_id.data.array.is_null_terminated = is_null_terminated;
     auto existing_entry = g->type_table.maybe_get(type_id);
     if (existing_entry) {
         return existing_entry->value;
@@ -769,12 +770,14 @@ ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size) {
     buf_resize(&entry->name, 0);
     buf_appendf(&entry->name, "[%" ZIG_PRI_u64 "]%s", array_size, buf_ptr(&child_type->name));
 
-    entry->size_in_bits = child_type->size_in_bits * array_size;
+    size_t full_array_size = array_size + (is_null_terminated ? 1 : 0);
+    entry->size_in_bits = child_type->size_in_bits * full_array_size;
     entry->abi_align = child_type->abi_align;
-    entry->abi_size = child_type->abi_size * array_size;
+    entry->abi_size = child_type->abi_size * full_array_size;
 
     entry->data.array.child_type = child_type;
     entry->data.array.len = array_size;
+    entry->data.array.is_null_terminated = is_null_terminated;
 
     g->type_table.put(type_id, entry);
     return entry;
@@ -782,7 +785,7 @@ ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size) {
 
 ZigType *get_slice_type(CodeGen *g, ZigType *ptr_type) {
     assert(ptr_type->id == ZigTypeIdPointer);
-    assert(ptr_type->data.pointer.ptr_len == PtrLenUnknown);
+    assert(ptr_type->data.pointer.ptr_len == PtrLenUnknown || ptr_type->data.pointer.ptr_len == PtrLenNull);
 
     ZigType **parent_pointer = &ptr_type->data.pointer.slice_parent;
     if (*parent_pointer) {
@@ -5615,7 +5618,7 @@ void init_const_str_lit(CodeGen *g, ConstExprValue *const_val, Buf *str) {
     }
 
     const_val->special = ConstValSpecialStatic;
-    const_val->type = get_array_type(g, g->builtin_types.entry_u8, buf_len(str));
+    const_val->type = get_array_type(g, g->builtin_types.entry_u8, buf_len(str), false);
     const_val->data.x_array.special = ConstArraySpecialBuf;
     const_val->data.x_array.data.s_buf = str;
 
@@ -5633,7 +5636,7 @@ void init_const_c_str_lit(CodeGen *g, ConstExprValue *const_val, Buf *str) {
     size_t len_with_null = buf_len(str) + 1;
     ConstExprValue *array_val = create_const_vals(1);
     array_val->special = ConstValSpecialStatic;
-    array_val->type = get_array_type(g, g->builtin_types.entry_u8, len_with_null);
+    array_val->type = get_array_type(g, g->builtin_types.entry_u8, len_with_null, false);
     // TODO buf optimization
     array_val->data.x_array.data.s_none.elements = create_const_vals(len_with_null);
     for (size_t i = 0; i < buf_len(str); i += 1) {
@@ -6071,7 +6074,7 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
 
             fields.append({"@stack_trace", get_stack_trace_type(g), 0});
             fields.append({"@instruction_addresses",
-                    get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count), 0});
+                    get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count, false), 0});
         }
 
         frame_type->data.frame.locals_struct = get_struct_type(g, buf_ptr(&frame_type->name),
@@ -6279,7 +6282,7 @@ static Error resolve_async_frame(CodeGen *g, ZigType *frame_type) {
     if (codegen_fn_has_err_ret_tracing_stack(g, fn, true)) {
         fields.append({"@stack_trace", get_stack_trace_type(g), 0});
         fields.append({"@instruction_addresses",
-                get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count), 0});
+                get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count, false), 0});
     }
 
     for (size_t alloca_i = 0; alloca_i < fn->alloca_gen_list.length; alloca_i += 1) {
@@ -7043,8 +7046,9 @@ uint32_t type_id_hash(TypeId x) {
                 (((uint32_t)x.data.pointer.vector_index) ^ (uint32_t)0x19199716) +
                 (((uint32_t)x.data.pointer.host_int_bytes) ^ (uint32_t)529908881);
         case ZigTypeIdArray:
-            return hash_ptr(x.data.array.child_type) +
-                ((uint32_t)x.data.array.size ^ (uint32_t)2122979968);
+            return hash_ptr(x.data.array.child_type) *
+                ((uint32_t)x.data.array.size ^ (uint32_t)2122979968) *
+                ((uint32_t)x.data.array.is_null_terminated ^ (uint32_t)2048352596);
         case ZigTypeIdInt:
             return (x.data.integer.is_signed ? (uint32_t)2652528194 : (uint32_t)163929201) +
                     (((uint32_t)x.data.integer.bit_count) ^ (uint32_t)2998081557);
@@ -7106,7 +7110,8 @@ bool type_id_eql(TypeId a, TypeId b) {
                 );
         case ZigTypeIdArray:
             return a.data.array.child_type == b.data.array.child_type &&
-                a.data.array.size == b.data.array.size;
+                a.data.array.size == b.data.array.size &&
+                a.data.array.is_null_terminated == b.data.array.is_null_terminated;
         case ZigTypeIdInt:
             return a.data.integer.is_signed == b.data.integer.is_signed &&
                 a.data.integer.bit_count == b.data.integer.bit_count;
@@ -8292,7 +8297,7 @@ static void resolve_llvm_types_union(CodeGen *g, ZigType *union_type, ResolveSta
         size_t padding_bytes = union_type->data.unionation.union_abi_size - most_aligned_union_member->type_entry->abi_size;
         if (padding_bytes > 0) {
             ZigType *u8_type = get_int_type(g, false, 8);
-            ZigType *padding_array = get_array_type(g, u8_type, padding_bytes);
+            ZigType *padding_array = get_array_type(g, u8_type, padding_bytes, false);
             LLVMTypeRef union_element_types[] = {
                 most_aligned_union_member->type_entry->llvm_type,
                 get_llvm_type(g, padding_array),
@@ -8326,7 +8331,7 @@ static void resolve_llvm_types_union(CodeGen *g, ZigType *union_type, ResolveSta
         union_type_ref = get_llvm_type(g, most_aligned_union_member->type_entry);
     } else {
         ZigType *u8_type = get_int_type(g, false, 8);
-        ZigType *padding_array = get_array_type(g, u8_type, padding_bytes);
+        ZigType *padding_array = get_array_type(g, u8_type, padding_bytes, false);
         LLVMTypeRef union_element_types[] = {
             get_llvm_type(g, most_aligned_union_member->type_entry),
             get_llvm_type(g, padding_array),
src/analyze.hpp
@@ -33,7 +33,7 @@ ZigType **get_c_int_type_ptr(CodeGen *g, CIntType c_int_type);
 ZigType *get_c_int_type(CodeGen *g, CIntType c_int_type);
 ZigType *get_fn_type(CodeGen *g, FnTypeId *fn_type_id);
 ZigType *get_optional_type(CodeGen *g, ZigType *child_type);
-ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size);
+ZigType *get_array_type(CodeGen *g, ZigType *child_type, uint64_t array_size, bool is_null_terminated);
 ZigType *get_slice_type(CodeGen *g, ZigType *ptr_type);
 ZigType *get_partial_container_type(CodeGen *g, Scope *scope, ContainerKind kind,
         AstNode *decl_node, const char *full_name, Buf *bare_name, ContainerLayout layout);
src/codegen.cpp
@@ -7465,7 +7465,7 @@ static void do_code_gen(CodeGen *g) {
             !is_async && !have_err_ret_trace_arg;
         LLVMValueRef err_ret_array_val = nullptr;
         if (have_err_ret_trace_stack) {
-            ZigType *array_type = get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count);
+            ZigType *array_type = get_array_type(g, g->builtin_types.entry_usize, stack_trace_ptr_count, false);
             err_ret_array_val = build_alloca(g, array_type, "error_return_trace_addresses", get_abi_alignment(g, array_type));
 
             (void)get_llvm_type(g, get_stack_trace_type(g));
@@ -9067,7 +9067,7 @@ static void create_test_compile_var_and_add_test_runner(CodeGen *g) {
         zig_unreachable();
 
     ConstExprValue *test_fn_array = create_const_vals(1);
-    test_fn_array->type = get_array_type(g, struct_type, g->test_fns.length);
+    test_fn_array->type = get_array_type(g, struct_type, g->test_fns.length, false);
     test_fn_array->special = ConstValSpecialStatic;
     test_fn_array->data.x_array.data.s_none.elements = create_const_vals(g->test_fns.length);
 
src/ir.cpp
@@ -1772,11 +1772,12 @@ static IrInstruction *ir_build_set_float_mode(IrBuilder *irb, Scope *scope, AstN
 }
 
 static IrInstruction *ir_build_array_type(IrBuilder *irb, Scope *scope, AstNode *source_node, IrInstruction *size,
-        IrInstruction *child_type)
+        IrInstruction *child_type, bool is_null_terminated)
 {
     IrInstructionArrayType *instruction = ir_build_instruction<IrInstructionArrayType>(irb, scope, source_node);
     instruction->size = size;
     instruction->child_type = child_type;
+    instruction->is_null_terminated = is_null_terminated;
 
     ir_ref_instruction(size, irb->current_basic_block);
     ir_ref_instruction(child_type, irb->current_basic_block);
@@ -1795,7 +1796,8 @@ static IrInstruction *ir_build_anyframe_type(IrBuilder *irb, Scope *scope, AstNo
     return &instruction->base;
 }
 static IrInstruction *ir_build_slice_type(IrBuilder *irb, Scope *scope, AstNode *source_node,
-        IrInstruction *child_type, bool is_const, bool is_volatile, IrInstruction *align_value, bool is_allow_zero)
+        IrInstruction *child_type, bool is_const, bool is_volatile, IrInstruction *align_value, bool is_allow_zero,
+        bool is_null_terminated)
 {
     IrInstructionSliceType *instruction = ir_build_instruction<IrInstructionSliceType>(irb, scope, source_node);
     instruction->is_const = is_const;
@@ -1803,6 +1805,7 @@ static IrInstruction *ir_build_slice_type(IrBuilder *irb, Scope *scope, AstNode
     instruction->child_type = child_type;
     instruction->align_value = align_value;
     instruction->is_allow_zero = is_allow_zero;
+    instruction->is_null_terminated = is_null_terminated;
 
     ir_ref_instruction(child_type, irb->current_basic_block);
     if (align_value) ir_ref_instruction(align_value, irb->current_basic_block);
@@ -6216,7 +6219,7 @@ static IrInstruction *ir_gen_container_init_expr(IrBuilder *irb, Scope *scope, A
                 return elem_type;
             size_t item_count = container_init_expr->entries.length;
             IrInstruction *item_count_inst = ir_build_const_usize(irb, scope, node, item_count);
-            container_type = ir_build_array_type(irb, scope, node, item_count_inst, elem_type);
+            container_type = ir_build_array_type(irb, scope, node, item_count_inst, elem_type, false);
         } else {
             container_type = ir_gen_node(irb, container_init_expr->type, scope);
             if (container_type == irb->codegen->invalid_instruction)
@@ -6944,6 +6947,7 @@ static IrInstruction *ir_gen_array_type(IrBuilder *irb, Scope *scope, AstNode *n
     bool is_const = node->data.array_type.is_const;
     bool is_volatile = node->data.array_type.is_volatile;
     bool is_allow_zero = node->data.array_type.allow_zero_token != nullptr;
+    bool is_null_terminated = node->data.array_type.is_null_terminated;
     AstNode *align_expr = node->data.array_type.align_expr;
 
     Scope *comptime_scope = create_comptime_scope(irb->codegen, node, scope);
@@ -6973,7 +6977,7 @@ static IrInstruction *ir_gen_array_type(IrBuilder *irb, Scope *scope, AstNode *n
         if (child_type == irb->codegen->invalid_instruction)
             return child_type;
 
-        return ir_build_array_type(irb, scope, node, size_value, child_type);
+        return ir_build_array_type(irb, scope, node, size_value, child_type, is_null_terminated);
     } else {
         IrInstruction *align_value;
         if (align_expr != nullptr) {
@@ -6988,7 +6992,8 @@ static IrInstruction *ir_gen_array_type(IrBuilder *irb, Scope *scope, AstNode *n
         if (child_type == irb->codegen->invalid_instruction)
             return child_type;
 
-        return ir_build_slice_type(irb, scope, node, child_type, is_const, is_volatile, align_value, is_allow_zero);
+        return ir_build_slice_type(irb, scope, node, child_type, is_const, is_volatile, align_value, is_allow_zero,
+                is_null_terminated);
     }
 }
 
@@ -10631,6 +10636,7 @@ static ZigType *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_node, ZigT
         // *[N]T to []T
         // *[N]T to E![]T
         if (cur_type->id == ZigTypeIdPointer &&
+            cur_type->data.pointer.ptr_len == PtrLenSingle &&
             cur_type->data.pointer.child_type->id == ZigTypeIdArray &&
             ((prev_type->id == ZigTypeIdErrorUnion && is_slice(prev_type->data.error_union.payload_type)) ||
                 is_slice(prev_type)))
@@ -10639,7 +10645,8 @@ static ZigType *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_node, ZigT
             ZigType *slice_type = (prev_type->id == ZigTypeIdErrorUnion) ?
                 prev_type->data.error_union.payload_type : prev_type;
             ZigType *slice_ptr_type = slice_type->data.structure.fields[slice_ptr_index]->type_entry;
-            if ((slice_ptr_type->data.pointer.is_const || array_type->data.array.len == 0) &&
+            if ((slice_ptr_type->data.pointer.is_const || array_type->data.array.len == 0 ||
+                        !cur_type->data.pointer.is_const) &&
                 types_match_const_cast_only(ira,
                     slice_ptr_type->data.pointer.child_type,
                     array_type->data.array.child_type, source_node, false).id == ConstCastResultIdOk)
@@ -10653,6 +10660,7 @@ static ZigType *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_node, ZigT
         // *[N]T to E![]T
         if (prev_type->id == ZigTypeIdPointer &&
             prev_type->data.pointer.child_type->id == ZigTypeIdArray &&
+            prev_type->data.pointer.ptr_len == PtrLenSingle &&
             ((cur_type->id == ZigTypeIdErrorUnion && is_slice(cur_type->data.error_union.payload_type)) ||
                 is_slice(cur_type)))
         {
@@ -10660,7 +10668,8 @@ static ZigType *ir_resolve_peer_types(IrAnalyze *ira, AstNode *source_node, ZigT
             ZigType *slice_type = (cur_type->id == ZigTypeIdErrorUnion) ?
                 cur_type->data.error_union.payload_type : cur_type;
             ZigType *slice_ptr_type = slice_type->data.structure.fields[slice_ptr_index]->type_entry;
-            if ((slice_ptr_type->data.pointer.is_const || array_type->data.array.len == 0) &&
+            if ((slice_ptr_type->data.pointer.is_const || array_type->data.array.len == 0 ||
+                        !prev_type->data.pointer.is_const) &&
                 types_match_const_cast_only(ira,
                     slice_ptr_type->data.pointer.child_type,
                     array_type->data.array.child_type, source_node, false).id == ConstCastResultIdOk)
@@ -14893,7 +14902,7 @@ static IrInstruction *ir_analyze_array_cat(IrAnalyze *ira, IrInstructionBinOp *i
     ConstExprValue *out_array_val;
     size_t new_len = (op1_array_end - op1_array_index) + (op2_array_end - op2_array_index);
     if (op1_type->id == ZigTypeIdArray || op2_type->id == ZigTypeIdArray) {
-        result->value.type = get_array_type(ira->codegen, child_type, new_len);
+        result->value.type = get_array_type(ira->codegen, child_type, new_len, false);
 
         out_array_val = out_val;
     } else if (is_slice(op1_type) || is_slice(op2_type)) {
@@ -14902,7 +14911,7 @@ static IrInstruction *ir_analyze_array_cat(IrAnalyze *ira, IrInstructionBinOp *i
         result->value.type = get_slice_type(ira->codegen, ptr_type);
         out_array_val = create_const_vals(1);
         out_array_val->special = ConstValSpecialStatic;
-        out_array_val->type = get_array_type(ira->codegen, child_type, new_len);
+        out_array_val->type = get_array_type(ira->codegen, child_type, new_len, false);
 
         out_val->data.x_struct.fields = alloc_const_vals_ptrs(2);
 
@@ -14923,7 +14932,7 @@ static IrInstruction *ir_analyze_array_cat(IrAnalyze *ira, IrInstructionBinOp *i
 
         out_array_val = create_const_vals(1);
         out_array_val->special = ConstValSpecialStatic;
-        out_array_val->type = get_array_type(ira->codegen, child_type, new_len);
+        out_array_val->type = get_array_type(ira->codegen, child_type, new_len, false);
         out_val->data.x_ptr.special = ConstPtrSpecialBaseArray;
         out_val->data.x_ptr.data.base_array.is_cstr = true;
         out_val->data.x_ptr.data.base_array.array_val = out_array_val;
@@ -14994,7 +15003,7 @@ static IrInstruction *ir_analyze_array_mult(IrAnalyze *ira, IrInstructionBinOp *
     ZigType *child_type = array_type->data.array.child_type;
 
     IrInstruction *result = ir_const(ira, &instruction->base,
-        get_array_type(ira->codegen, child_type, new_array_len));
+        get_array_type(ira->codegen, child_type, new_array_len, false));
     ConstExprValue *out_val = &result->value;
     if (array_val->data.x_array.special == ConstArraySpecialUndef) {
         out_val->data.x_array.special = ConstArraySpecialUndef;
@@ -19311,6 +19320,7 @@ static IrInstruction *ir_analyze_instruction_slice_type(IrAnalyze *ira,
     lazy_slice_type->is_const = slice_type_instruction->is_const;
     lazy_slice_type->is_volatile = slice_type_instruction->is_volatile;
     lazy_slice_type->is_allowzero = slice_type_instruction->is_allow_zero;
+    lazy_slice_type->is_null_terminated = slice_type_instruction->is_null_terminated;
 
     return result;
 }
@@ -19420,7 +19430,8 @@ static IrInstruction *ir_analyze_instruction_array_type(IrAnalyze *ira,
             {
                 if ((err = type_resolve(ira->codegen, child_type, ResolveStatusSizeKnown)))
                     return ira->codegen->invalid_instruction;
-                ZigType *result_type = get_array_type(ira->codegen, child_type, size);
+                ZigType *result_type = get_array_type(ira->codegen, child_type, size,
+                        array_type_instruction->is_null_terminated);
                 return ir_const_type(ira, &array_type_instruction->base, result_type);
             }
     }
@@ -20496,7 +20507,7 @@ static IrInstruction *ir_analyze_instruction_container_init_list(IrAnalyze *ira,
     if (container_type->id == ZigTypeIdArray) {
         ZigType *child_type = container_type->data.array.child_type;
         if (container_type->data.array.len != elem_count) {
-            ZigType *literal_type = get_array_type(ira->codegen, child_type, elem_count);
+            ZigType *literal_type = get_array_type(ira->codegen, child_type, elem_count, false);
 
             ir_add_error(ira, &instruction->base,
                 buf_sprintf("expected %s literal, found %s literal",
@@ -20983,7 +20994,7 @@ static Error ir_make_type_info_decls(IrAnalyze *ira, IrInstruction *source_instr
 
     ConstExprValue *declaration_array = create_const_vals(1);
     declaration_array->special = ConstValSpecialStatic;
-    declaration_array->type = get_array_type(ira->codegen, type_info_declaration_type, declaration_count);
+    declaration_array->type = get_array_type(ira->codegen, type_info_declaration_type, declaration_count, false);
     declaration_array->data.x_array.special = ConstArraySpecialNone;
     declaration_array->data.x_array.data.s_none.elements = create_const_vals(declaration_count);
     init_const_slice(ira->codegen, out_val, declaration_array, 0, declaration_count, false);
@@ -21128,7 +21139,7 @@ static Error ir_make_type_info_decls(IrAnalyze *ira, IrInstruction *source_instr
                     ConstExprValue *fn_arg_name_array = create_const_vals(1);
                     fn_arg_name_array->special = ConstValSpecialStatic;
                     fn_arg_name_array->type = get_array_type(ira->codegen,
-                            get_slice_type(ira->codegen, u8_ptr), fn_arg_count);
+                            get_slice_type(ira->codegen, u8_ptr), fn_arg_count, false);
                     fn_arg_name_array->data.x_array.special = ConstArraySpecialNone;
                     fn_arg_name_array->data.x_array.data.s_none.elements = create_const_vals(fn_arg_count);
 
@@ -21376,7 +21387,7 @@ static Error ir_make_type_info_value(IrAnalyze *ira, IrInstruction *source_instr
                 result->special = ConstValSpecialStatic;
                 result->type = ir_type_info_get_type(ira, "Array", nullptr);
 
-                ConstExprValue **fields = alloc_const_vals_ptrs(2);
+                ConstExprValue **fields = alloc_const_vals_ptrs(3);
                 result->data.x_struct.fields = fields;
 
                 // len: usize
@@ -21389,6 +21400,11 @@ static Error ir_make_type_info_value(IrAnalyze *ira, IrInstruction *source_instr
                 fields[1]->special = ConstValSpecialStatic;
                 fields[1]->type = ira->codegen->builtin_types.entry_type;
                 fields[1]->data.x_type = type_entry->data.array.child_type;
+                // is_null_terminated: bool
+                ensure_field_index(result->type, "is_null_terminated", 2);
+                fields[2]->special = ConstValSpecialStatic;
+                fields[2]->type = ira->codegen->builtin_types.entry_bool;
+                fields[2]->data.x_bool = type_entry->data.array.is_null_terminated;
 
                 break;
             }
@@ -21476,7 +21492,7 @@ static Error ir_make_type_info_value(IrAnalyze *ira, IrInstruction *source_instr
 
                 ConstExprValue *enum_field_array = create_const_vals(1);
                 enum_field_array->special = ConstValSpecialStatic;
-                enum_field_array->type = get_array_type(ira->codegen, type_info_enum_field_type, enum_field_count);
+                enum_field_array->type = get_array_type(ira->codegen, type_info_enum_field_type, enum_field_count, false);
                 enum_field_array->data.x_array.special = ConstArraySpecialNone;
                 enum_field_array->data.x_array.data.s_none.elements = create_const_vals(enum_field_count);
 
@@ -21524,7 +21540,7 @@ static Error ir_make_type_info_value(IrAnalyze *ira, IrInstruction *source_instr
                 uint32_t error_count = type_entry->data.error_set.err_count;
                 ConstExprValue *error_array = create_const_vals(1);
                 error_array->special = ConstValSpecialStatic;
-                error_array->type = get_array_type(ira->codegen, type_info_error_type, error_count);
+                error_array->type = get_array_type(ira->codegen, type_info_error_type, error_count, false);
                 error_array->data.x_array.special = ConstArraySpecialNone;
                 error_array->data.x_array.data.s_none.elements = create_const_vals(error_count);
 
@@ -21620,7 +21636,7 @@ static Error ir_make_type_info_value(IrAnalyze *ira, IrInstruction *source_instr
 
                 ConstExprValue *union_field_array = create_const_vals(1);
                 union_field_array->special = ConstValSpecialStatic;
-                union_field_array->type = get_array_type(ira->codegen, type_info_union_field_type, union_field_count);
+                union_field_array->type = get_array_type(ira->codegen, type_info_union_field_type, union_field_count, false);
                 union_field_array->data.x_array.special = ConstArraySpecialNone;
                 union_field_array->data.x_array.data.s_none.elements = create_const_vals(union_field_count);
 
@@ -21700,7 +21716,7 @@ static Error ir_make_type_info_value(IrAnalyze *ira, IrInstruction *source_instr
 
                 ConstExprValue *struct_field_array = create_const_vals(1);
                 struct_field_array->special = ConstValSpecialStatic;
-                struct_field_array->type = get_array_type(ira->codegen, type_info_struct_field_type, struct_field_count);
+                struct_field_array->type = get_array_type(ira->codegen, type_info_struct_field_type, struct_field_count, false);
                 struct_field_array->data.x_array.special = ConstArraySpecialNone;
                 struct_field_array->data.x_array.data.s_none.elements = create_const_vals(struct_field_count);
 
@@ -21803,7 +21819,7 @@ static Error ir_make_type_info_value(IrAnalyze *ira, IrInstruction *source_instr
 
                 ConstExprValue *fn_arg_array = create_const_vals(1);
                 fn_arg_array->special = ConstValSpecialStatic;
-                fn_arg_array->type = get_array_type(ira->codegen, type_info_fn_arg_type, fn_arg_count);
+                fn_arg_array->type = get_array_type(ira->codegen, type_info_fn_arg_type, fn_arg_count, false);
                 fn_arg_array->data.x_array.special = ConstArraySpecialNone;
                 fn_arg_array->data.x_array.data.s_none.elements = create_const_vals(fn_arg_count);
 
@@ -21983,7 +21999,8 @@ static ZigType *type_info_to_type(IrAnalyze *ira, IrInstruction *instruction, Zi
             assert(payload->type == ir_type_info_get_type(ira, "Array", nullptr));
             return get_array_type(ira->codegen,
                 get_const_field_meta_type(ira, payload, "child", 1),
-                bigint_as_u64(get_const_field_lit_int(ira, payload, "len", 0))
+                bigint_as_u64(get_const_field_lit_int(ira, payload, "len", 0)),
+                get_const_field_bool(ira, payload, "is_null_terminated", 2)
             );
         case ZigTypeIdComptimeFloat:
             return ira->codegen->builtin_types.entry_num_lit_float;
@@ -22366,7 +22383,7 @@ static IrInstruction *ir_analyze_instruction_embed_file(IrAnalyze *ira, IrInstru
     }
 
     ZigType *result_type = get_array_type(ira->codegen,
-            ira->codegen->builtin_types.entry_u8, buf_len(file_contents));
+            ira->codegen->builtin_types.entry_u8, buf_len(file_contents), false);
     IrInstruction *result = ir_const(ira, &instruction->base, result_type);
     init_const_str_lit(ira->codegen, &result->value, file_contents);
     return result;
@@ -27581,7 +27598,9 @@ static Error ir_resolve_lazy_raw(AstNode *source_node, ConstExprValue *val) {
             if ((err = type_resolve(ira->codegen, elem_type, needed_status)))
                 return err;
             ZigType *slice_ptr_type = get_pointer_to_type_extra(ira->codegen, elem_type,
-                    lazy_slice_type->is_const, lazy_slice_type->is_volatile, PtrLenUnknown, align_bytes,
+                    lazy_slice_type->is_const, lazy_slice_type->is_volatile,
+                    lazy_slice_type->is_null_terminated ? PtrLenNull : PtrLenUnknown,
+                    align_bytes,
                     0, 0, lazy_slice_type->is_allowzero);
             val->special = ConstValSpecialStatic;
             assert(val->type->id == ZigTypeIdMetaType);
src-self-hosted/translate_c.zig
@@ -1118,6 +1118,7 @@ fn transCreateNodePtrType(
                 .align_info = null,
                 .const_token = if (is_const) try appendToken(c, .Keyword_const, "const") else null,
                 .volatile_token = if (is_volatile) try appendToken(c, .Keyword_volatile, "volatile") else null,
+                .null_token = null,
             },
         },
         .rhs = undefined, // translate and set afterward
test/stage1/behavior/if.zig
@@ -81,6 +81,10 @@ test "if prongs cast to expected type instead of peer type resolution" {
             var x: i32 = 0;
             x = if (f) 1 else 2;
             expect(x == 2);
+
+            var b = true;
+            const y: i32 = if (b) 1 else 2;
+            expect(y == 1);
         }
     };
     S.doTheTest(false);
test/stage1/behavior/type.zig
@@ -11,103 +11,122 @@ fn testTypes(comptime types: []const type) void {
 }
 
 test "Type.MetaType" {
-    testing.expect(type == @Type(TypeInfo { .Type = undefined }));
-    testTypes([_]type {type});
+    testing.expect(type == @Type(TypeInfo{ .Type = undefined }));
+    testTypes([_]type{type});
 }
 
 test "Type.Void" {
-    testing.expect(void == @Type(TypeInfo { .Void = undefined }));
-    testTypes([_]type {void});
+    testing.expect(void == @Type(TypeInfo{ .Void = undefined }));
+    testTypes([_]type{void});
 }
 
 test "Type.Bool" {
-    testing.expect(bool == @Type(TypeInfo { .Bool = undefined }));
-    testTypes([_]type {bool});
+    testing.expect(bool == @Type(TypeInfo{ .Bool = undefined }));
+    testTypes([_]type{bool});
 }
 
 test "Type.NoReturn" {
-    testing.expect(noreturn == @Type(TypeInfo { .NoReturn = undefined }));
-    testTypes([_]type {noreturn});
+    testing.expect(noreturn == @Type(TypeInfo{ .NoReturn = undefined }));
+    testTypes([_]type{noreturn});
 }
 
 test "Type.Int" {
-    testing.expect(u1 == @Type(TypeInfo { .Int = TypeInfo.Int { .is_signed = false, .bits = 1 } }));
-    testing.expect(i1 == @Type(TypeInfo { .Int = TypeInfo.Int { .is_signed = true, .bits = 1 } }));
-    testing.expect(u8 == @Type(TypeInfo { .Int = TypeInfo.Int { .is_signed = false, .bits = 8 } }));
-    testing.expect(i8 == @Type(TypeInfo { .Int = TypeInfo.Int { .is_signed = true, .bits = 8 } }));
-    testing.expect(u64 == @Type(TypeInfo { .Int = TypeInfo.Int { .is_signed = false, .bits = 64 } }));
-    testing.expect(i64 == @Type(TypeInfo { .Int = TypeInfo.Int { .is_signed = true, .bits = 64 } }));
-    testTypes([_]type {u8,u32,i64});
+    testing.expect(u1 == @Type(TypeInfo{ .Int = TypeInfo.Int{ .is_signed = false, .bits = 1 } }));
+    testing.expect(i1 == @Type(TypeInfo{ .Int = TypeInfo.Int{ .is_signed = true, .bits = 1 } }));
+    testing.expect(u8 == @Type(TypeInfo{ .Int = TypeInfo.Int{ .is_signed = false, .bits = 8 } }));
+    testing.expect(i8 == @Type(TypeInfo{ .Int = TypeInfo.Int{ .is_signed = true, .bits = 8 } }));
+    testing.expect(u64 == @Type(TypeInfo{ .Int = TypeInfo.Int{ .is_signed = false, .bits = 64 } }));
+    testing.expect(i64 == @Type(TypeInfo{ .Int = TypeInfo.Int{ .is_signed = true, .bits = 64 } }));
+    testTypes([_]type{ u8, u32, i64 });
 }
 
 test "Type.Float" {
-    testing.expect(f16  == @Type(TypeInfo { .Float = TypeInfo.Float { .bits = 16 } }));
-    testing.expect(f32  == @Type(TypeInfo { .Float = TypeInfo.Float { .bits = 32 } }));
-    testing.expect(f64  == @Type(TypeInfo { .Float = TypeInfo.Float { .bits = 64 } }));
-    testing.expect(f128 == @Type(TypeInfo { .Float = TypeInfo.Float { .bits = 128 } }));
-    testTypes([_]type {f16, f32, f64, f128});
+    testing.expect(f16 == @Type(TypeInfo{ .Float = TypeInfo.Float{ .bits = 16 } }));
+    testing.expect(f32 == @Type(TypeInfo{ .Float = TypeInfo.Float{ .bits = 32 } }));
+    testing.expect(f64 == @Type(TypeInfo{ .Float = TypeInfo.Float{ .bits = 64 } }));
+    testing.expect(f128 == @Type(TypeInfo{ .Float = TypeInfo.Float{ .bits = 128 } }));
+    testTypes([_]type{ f16, f32, f64, f128 });
 }
 
 test "Type.Pointer" {
-    testTypes([_]type {
+    testTypes([_]type{
         // One Value Pointer Types
-        *u8, *const u8,
-        *volatile u8, *const volatile u8,
-        *align(4) u8, *const align(4) u8,
-        *volatile align(4) u8, *const volatile align(4) u8,
-        *align(8) u8, *const align(8) u8,
-        *volatile align(8) u8, *const volatile align(8) u8,
-        *allowzero u8, *const allowzero u8,
-        *volatile allowzero u8, *const volatile allowzero u8,
-        *align(4) allowzero u8, *const align(4) allowzero u8,
-        *volatile align(4) allowzero u8, *const volatile align(4) allowzero u8,
+        *u8,                               *const u8,
+        *volatile u8,                      *const volatile u8,
+        *align(4) u8,                      *align(4) const u8,
+        *align(4) volatile u8,             *align(4) const volatile u8,
+        *align(8) u8,                      *align(8) const u8,
+        *align(8) volatile u8,             *align(8) const volatile u8,
+        *allowzero u8,                     *allowzero const u8,
+        *allowzero volatile u8,            *allowzero const volatile u8,
+        *allowzero align(4) u8,            *allowzero align(4) const u8,
+        *allowzero align(4) volatile u8,   *allowzero align(4) const volatile u8,
         // Many Values Pointer Types
-        [*]u8, [*]const u8,
-        [*]volatile u8, [*]const volatile u8,
-        [*]align(4) u8, [*]const align(4) u8,
-        [*]volatile align(4) u8, [*]const volatile align(4) u8,
-        [*]align(8) u8, [*]const align(8) u8,
-        [*]volatile align(8) u8, [*]const volatile align(8) u8,
-        [*]allowzero u8, [*]const allowzero u8,
-        [*]volatile allowzero u8, [*]const volatile allowzero u8,
-        [*]align(4) allowzero u8, [*]const align(4) allowzero u8,
-        [*]volatile align(4) allowzero u8, [*]const volatile align(4) allowzero u8,
+        [*]u8,                             [*]const u8,
+        [*]volatile u8,                    [*]const volatile u8,
+        [*]align(4) u8,                    [*]align(4) const u8,
+        [*]align(4) volatile u8,           [*]align(4) const volatile u8,
+        [*]align(8) u8,                    [*]align(8) const u8,
+        [*]align(8) volatile u8,           [*]align(8) const volatile u8,
+        [*]allowzero u8,                   [*]allowzero const u8,
+        [*]allowzero volatile u8,          [*]allowzero const volatile u8,
+        [*]allowzero align(4) u8,          [*]allowzero align(4) const u8,
+        [*]allowzero align(4) volatile u8, [*]allowzero align(4) const volatile u8,
         // Slice Types
-        []u8, []const u8,
-        []volatile u8, []const volatile u8,
-        []align(4) u8, []const align(4) u8,
-        []volatile align(4) u8, []const volatile align(4) u8,
-        []align(8) u8, []const align(8) u8,
-        []volatile align(8) u8, []const volatile align(8) u8,
-        []allowzero u8, []const allowzero u8,
-        []volatile allowzero u8, []const volatile allowzero u8,
-        []align(4) allowzero u8, []const align(4) allowzero u8,
-        []volatile align(4) allowzero u8, []const volatile align(4) allowzero u8,
+        []u8,                              []const u8,
+        []volatile u8,                     []const volatile u8,
+        []align(4) u8,                     []align(4) const u8,
+        []align(4) volatile u8,            []align(4) const volatile u8,
+        []align(8) u8,                     []align(8) const u8,
+        []align(8) volatile u8,            []align(8) const volatile u8,
+        []allowzero u8,                    []allowzero const u8,
+        []allowzero volatile u8,           []allowzero const volatile u8,
+        []allowzero align(4) u8,           []allowzero align(4) const u8,
+        []allowzero align(4) volatile u8,  []allowzero align(4) const volatile u8,
         // C Pointer Types
-        [*c]u8, [*c]const u8,
-        [*c]volatile u8, [*c]const volatile u8,
-        [*c]align(4) u8, [*c]const align(4) u8,
-        [*c]volatile align(4) u8, [*c]const volatile align(4) u8,
-        [*c]align(8) u8, [*c]const align(8) u8,
-        [*c]volatile align(8) u8, [*c]const volatile align(8) u8,
+        [*c]u8,                            [*c]const u8,
+        [*c]volatile u8,                   [*c]const volatile u8,
+        [*c]align(4) u8,                   [*c]align(4) const u8,
+        [*c]align(4) volatile u8,          [*c]align(4) const volatile u8,
+        [*c]align(8) u8,                   [*c]align(8) const u8,
+        [*c]align(8) volatile u8,          [*c]align(8) const volatile u8,
     });
 }
 
 test "Type.Array" {
-    testing.expect([123]u8 == @Type(TypeInfo { .Array = TypeInfo.Array { .len = 123, .child = u8 } }));
-    testing.expect([2]u32 == @Type(TypeInfo { .Array = TypeInfo.Array { .len = 2, .child = u32 } }));
-    testTypes([_]type {[1]u8, [30]usize, [7]bool});
+    testing.expect([123]u8 == @Type(TypeInfo{
+        .Array = TypeInfo.Array{
+            .len = 123,
+            .child = u8,
+            .is_null_terminated = false,
+        },
+    }));
+    testing.expect([2]u32 == @Type(TypeInfo{
+        .Array = TypeInfo.Array{
+            .len = 2,
+            .child = u32,
+            .is_null_terminated = false,
+        },
+    }));
+    testing.expect([2]null u32 == @Type(TypeInfo{
+        .Array = TypeInfo.Array{
+            .len = 2,
+            .child = u32,
+            .is_null_terminated = true,
+        },
+    }));
+    testTypes([_]type{ [1]u8, [30]usize, [7]bool });
 }
 
 test "Type.ComptimeFloat" {
-    testTypes([_]type {comptime_float});
+    testTypes([_]type{comptime_float});
 }
 test "Type.ComptimeInt" {
-    testTypes([_]type {comptime_int});
+    testTypes([_]type{comptime_int});
 }
 test "Type.Undefined" {
-    testTypes([_]type {@typeOf(undefined)});
+    testTypes([_]type{@typeOf(undefined)});
 }
 test "Type.Null" {
-    testTypes([_]type {@typeOf(null)});
+    testTypes([_]type{@typeOf(null)});
 }
test/stage1/behavior/type_info.zig
@@ -46,6 +46,7 @@ fn testPointer() void {
     expect(u32_ptr_info.Pointer.is_volatile == false);
     expect(u32_ptr_info.Pointer.alignment == @alignOf(u32));
     expect(u32_ptr_info.Pointer.child == u32);
+    expect(u32_ptr_info.Pointer.is_null_terminated == false);
 }
 
 test "type info: unknown length pointer type info" {
@@ -55,14 +56,34 @@ test "type info: unknown length pointer type info" {
 
 fn testUnknownLenPtr() void {
     const u32_ptr_info = @typeInfo([*]const volatile f64);
-    expect(@as(TypeId,u32_ptr_info) == TypeId.Pointer);
+    expect(@as(TypeId, u32_ptr_info) == TypeId.Pointer);
     expect(u32_ptr_info.Pointer.size == TypeInfo.Pointer.Size.Many);
     expect(u32_ptr_info.Pointer.is_const == true);
     expect(u32_ptr_info.Pointer.is_volatile == true);
+    expect(u32_ptr_info.Pointer.is_null_terminated == false);
     expect(u32_ptr_info.Pointer.alignment == @alignOf(f64));
     expect(u32_ptr_info.Pointer.child == f64);
 }
 
+test "type info: null terminated pointer type info" {
+    testNullTerminatedPtr();
+    comptime testNullTerminatedPtr();
+}
+
+fn testNullTerminatedPtr() void {
+    const ptr_info = @typeInfo([*]null u8);
+    expect(@as(TypeId, ptr_info) == TypeId.Pointer);
+    expect(ptr_info.Pointer.size == TypeInfo.Pointer.Size.Many);
+    expect(ptr_info.Pointer.is_const == false);
+    expect(ptr_info.Pointer.is_volatile == false);
+    expect(ptr_info.Pointer.is_null_terminated == true);
+
+    expect(@typeInfo([]null u8).Pointer.is_null_terminated == true);
+    expect(@typeInfo([10]null u8).Array.is_null_terminated == true);
+    expect(@typeInfo([10]null u8).Array.len == 10);
+    expect(@sizeOf([10]null u8) == 11);
+}
+
 test "type info: C pointer type info" {
     testCPtr();
     comptime testCPtr();
@@ -70,7 +91,7 @@ test "type info: C pointer type info" {
 
 fn testCPtr() void {
     const ptr_info = @typeInfo([*c]align(4) const i8);
-    expect(@as(TypeId,ptr_info) == TypeId.Pointer);
+    expect(@as(TypeId, ptr_info) == TypeId.Pointer);
     expect(ptr_info.Pointer.size == TypeInfo.Pointer.Size.C);
     expect(ptr_info.Pointer.is_const);
     expect(!ptr_info.Pointer.is_volatile);
@@ -288,13 +309,13 @@ test "type info: anyframe and anyframe->T" {
 fn testAnyFrame() void {
     {
         const anyframe_info = @typeInfo(anyframe->i32);
-        expect(@as(TypeId,anyframe_info) == .AnyFrame);
+        expect(@as(TypeId, anyframe_info) == .AnyFrame);
         expect(anyframe_info.AnyFrame.child.? == i32);
     }
 
     {
         const anyframe_info = @typeInfo(anyframe);
-        expect(@as(TypeId,anyframe_info) == .AnyFrame);
+        expect(@as(TypeId, anyframe_info) == .AnyFrame);
         expect(anyframe_info.AnyFrame.child == null);
     }
 }
@@ -334,7 +355,7 @@ test "type info: extern fns with and without lib names" {
             if (std.mem.eql(u8, decl.name, "bar1")) {
                 expect(decl.data.Fn.lib_name == null);
             } else {
-                std.testing.expectEqual(@as([]const u8,"cool"), decl.data.Fn.lib_name.?);
+                std.testing.expectEqual(@as([]const u8, "cool"), decl.data.Fn.lib_name.?);
             }
         }
     }