Commit e851d89113

Andrew Kelley <andrew@ziglang.org>
2021-10-13 23:16:01
Sema: implement comptime `coerce_result_ptr` and `alloc`
This is progress towards being able to use `builtin.cpu.arch` instead of the `stage2_arch` workaround. The next blocker is comptime `elemVal`.
1 parent 2a701a9
Changed files (4)
src/Sema.zig
@@ -1340,29 +1340,50 @@ fn zirCoerceResultPtr(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileE
     const pointee_ty = try sema.resolveType(block, src, bin_inst.lhs);
     const ptr = sema.resolveInst(bin_inst.rhs);
 
-    // Create a runtime bitcast instruction with exactly the type the pointer wants.
     const ptr_ty = try Type.ptr(sema.arena, .{
         .pointee_type = pointee_ty,
         .@"addrspace" = target_util.defaultAddressSpace(sema.mod.getTarget(), .local),
     });
-    try sema.requireRuntimeBlock(block, src);
-    const bitcasted_ptr = try block.addTyOp(.bitcast, ptr_ty, ptr);
 
     if (Air.refToIndex(ptr)) |ptr_inst| {
         if (sema.air_instructions.items(.tag)[ptr_inst] == .constant) {
             const air_datas = sema.air_instructions.items(.data);
             const ptr_val = sema.air_values.items[air_datas[ptr_inst].ty_pl.payload];
-            if (ptr_val.castTag(.inferred_alloc)) |inferred_alloc| {
-                // Add the stored instruction to the set we will use to resolve peer types
-                // for the inferred allocation.
-                // This instruction will not make it to codegen; it is only to participate
-                // in the `stored_inst_list` of the `inferred_alloc`.
-                const operand = try block.addTyOp(.bitcast, pointee_ty, .void_value);
-                try inferred_alloc.data.stored_inst_list.append(sema.arena, operand);
+            switch (ptr_val.tag()) {
+                .inferred_alloc => {
+                    const inferred_alloc = &ptr_val.castTag(.inferred_alloc).?.data;
+                    // Add the stored instruction to the set we will use to resolve peer types
+                    // for the inferred allocation.
+                    // This instruction will not make it to codegen; it is only to participate
+                    // in the `stored_inst_list` of the `inferred_alloc`.
+                    const operand = try block.addTyOp(.bitcast, pointee_ty, .void_value);
+                    try inferred_alloc.stored_inst_list.append(sema.arena, operand);
+                },
+                .inferred_alloc_comptime => {
+                    const iac = ptr_val.castTag(.inferred_alloc_comptime).?;
+                    // There will be only one coerce_result_ptr because we are running at comptime.
+                    // The alloc will turn into a Decl.
+                    var anon_decl = try block.startAnonDecl();
+                    defer anon_decl.deinit();
+                    iac.data = try anon_decl.finish(
+                        try pointee_ty.copy(anon_decl.arena()),
+                        Value.undef,
+                    );
+                    return sema.addConstant(
+                        ptr_ty,
+                        try Value.Tag.decl_ref_mut.create(sema.arena, .{
+                            .decl = iac.data,
+                            .runtime_index = block.runtime_index,
+                        }),
+                    );
+                },
+                .decl_ref_mut => return sema.addConstant(ptr_ty, ptr_val),
+                else => {},
             }
         }
     }
-
+    try sema.requireRuntimeBlock(block, src);
+    const bitcasted_ptr = try block.addTyOp(.bitcast, ptr_ty, ptr);
     return bitcasted_ptr;
 }
 
@@ -1996,6 +2017,9 @@ fn zirAlloc(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air.I
     const ty_src: LazySrcLoc = .{ .node_offset_var_decl_ty = inst_data.src_node };
     const var_decl_src = inst_data.src();
     const var_type = try sema.resolveType(block, ty_src, inst_data.operand);
+    if (block.is_comptime) {
+        return sema.analyzeComptimeAlloc(block, var_type);
+    }
     const ptr_type = try Type.ptr(sema.arena, .{
         .pointee_type = var_type,
         .@"addrspace" = target_util.defaultAddressSpace(sema.mod.getTarget(), .local),
@@ -13418,9 +13442,10 @@ fn analyzeComptimeAlloc(
     defer anon_decl.deinit();
     const decl = try anon_decl.finish(
         try var_type.copy(anon_decl.arena()),
-        // AstGen guarantees there will be a store before the first load, so we put a value
-        // here indicating there is no valid value.
-        Value.initTag(.unreachable_value),
+        // There will be stores before the first load, but they may be to sub-elements or
+        // sub-fields. So we need to initialize with undef to allow the mechanism to expand
+        // into fields/elements and have those overridden with stored values.
+        Value.undef,
     );
     try sema.mod.declareDeclDependency(sema.owner_decl, decl);
     return sema.addConstant(ptr_type, try Value.Tag.decl_ref_mut.create(sema.arena, .{
test/behavior/slice.zig
@@ -3,336 +3,3 @@ const expect = std.testing.expect;
 const expectEqualSlices = std.testing.expectEqualSlices;
 const expectEqual = std.testing.expectEqual;
 const mem = std.mem;
-
-const x = @intToPtr([*]i32, 0x1000)[0..0x500];
-const y = x[0x100..];
-test "compile time slice of pointer to hard coded address" {
-    try expect(@ptrToInt(x) == 0x1000);
-    try expect(x.len == 0x500);
-
-    try expect(@ptrToInt(y) == 0x1100);
-    try expect(y.len == 0x400);
-}
-
-test "runtime safety lets us slice from len..len" {
-    var an_array = [_]u8{
-        1,
-        2,
-        3,
-    };
-    try expect(mem.eql(u8, sliceFromLenToLen(an_array[0..], 3, 3), ""));
-}
-
-fn sliceFromLenToLen(a_slice: []u8, start: usize, end: usize) []u8 {
-    return a_slice[start..end];
-}
-
-test "implicitly cast array of size 0 to slice" {
-    var msg = [_]u8{};
-    try assertLenIsZero(&msg);
-}
-
-fn assertLenIsZero(msg: []const u8) !void {
-    try expect(msg.len == 0);
-}
-
-test "C pointer" {
-    var buf: [*c]const u8 = "kjdhfkjdhfdkjhfkfjhdfkjdhfkdjhfdkjhf";
-    var len: u32 = 10;
-    var slice = buf[0..len];
-    try expectEqualSlices(u8, "kjdhfkjdhf", slice);
-}
-
-test "C pointer slice access" {
-    var buf: [10]u32 = [1]u32{42} ** 10;
-    const c_ptr = @ptrCast([*c]const u32, &buf);
-
-    var runtime_zero: usize = 0;
-    comptime try expectEqual([]const u32, @TypeOf(c_ptr[runtime_zero..1]));
-    comptime try expectEqual(*const [1]u32, @TypeOf(c_ptr[0..1]));
-
-    for (c_ptr[0..5]) |*cl| {
-        try expectEqual(@as(u32, 42), cl.*);
-    }
-}
-
-fn sliceSum(comptime q: []const u8) i32 {
-    comptime var result = 0;
-    inline for (q) |item| {
-        result += item;
-    }
-    return result;
-}
-
-test "comptime slices are disambiguated" {
-    try expect(sliceSum(&[_]u8{ 1, 2 }) == 3);
-    try expect(sliceSum(&[_]u8{ 3, 4 }) == 7);
-}
-
-test "slice type with custom alignment" {
-    const LazilyResolvedType = struct {
-        anything: i32,
-    };
-    var slice: []align(32) LazilyResolvedType = undefined;
-    var array: [10]LazilyResolvedType align(32) = undefined;
-    slice = &array;
-    slice[1].anything = 42;
-    try expect(array[1].anything == 42);
-}
-
-test "access len index of sentinel-terminated slice" {
-    const S = struct {
-        fn doTheTest() !void {
-            var slice: [:0]const u8 = "hello";
-
-            try expect(slice.len == 5);
-            try expect(slice[5] == 0);
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "obtaining a null terminated slice" {
-    // here we have a normal array
-    var buf: [50]u8 = undefined;
-
-    buf[0] = 'a';
-    buf[1] = 'b';
-    buf[2] = 'c';
-    buf[3] = 0;
-
-    // now we obtain a null terminated slice:
-    const ptr = buf[0..3 :0];
-    _ = ptr;
-
-    var runtime_len: usize = 3;
-    const ptr2 = buf[0..runtime_len :0];
-    // ptr2 is a null-terminated slice
-    comptime try expect(@TypeOf(ptr2) == [:0]u8);
-    comptime try expect(@TypeOf(ptr2[0..2]) == *[2]u8);
-    var runtime_zero: usize = 0;
-    comptime try expect(@TypeOf(ptr2[runtime_zero..2]) == []u8);
-}
-
-test "empty array to slice" {
-    const S = struct {
-        fn doTheTest() !void {
-            const empty: []align(16) u8 = &[_]u8{};
-            const align_1: []align(1) u8 = empty;
-            const align_4: []align(4) u8 = empty;
-            const align_16: []align(16) u8 = empty;
-            try expectEqual(1, @typeInfo(@TypeOf(align_1)).Pointer.alignment);
-            try expectEqual(4, @typeInfo(@TypeOf(align_4)).Pointer.alignment);
-            try expectEqual(16, @typeInfo(@TypeOf(align_16)).Pointer.alignment);
-        }
-    };
-
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "@ptrCast slice to pointer" {
-    const S = struct {
-        fn doTheTest() !void {
-            var array align(@alignOf(u16)) = [5]u8{ 0xff, 0xff, 0xff, 0xff, 0xff };
-            var slice: []u8 = &array;
-            var ptr = @ptrCast(*u16, slice);
-            try expect(ptr.* == 65535);
-        }
-    };
-
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "slice syntax resulting in pointer-to-array" {
-    const S = struct {
-        fn doTheTest() !void {
-            try testArray();
-            try testArrayZ();
-            try testArray0();
-            try testArrayAlign();
-            try testPointer();
-            try testPointerZ();
-            try testPointer0();
-            try testPointerAlign();
-            try testSlice();
-            try testSliceZ();
-            try testSlice0();
-            try testSliceOpt();
-            try testSliceAlign();
-        }
-
-        fn testArray() !void {
-            var array = [5]u8{ 1, 2, 3, 4, 5 };
-            var slice = array[1..3];
-            comptime try expect(@TypeOf(slice) == *[2]u8);
-            try expect(slice[0] == 2);
-            try expect(slice[1] == 3);
-        }
-
-        fn testArrayZ() !void {
-            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
-            comptime try expect(@TypeOf(array[1..3]) == *[2]u8);
-            comptime try expect(@TypeOf(array[1..5]) == *[4:0]u8);
-            comptime try expect(@TypeOf(array[1..]) == *[4:0]u8);
-            comptime try expect(@TypeOf(array[1..3 :4]) == *[2:4]u8);
-        }
-
-        fn testArray0() !void {
-            {
-                var array = [0]u8{};
-                var slice = array[0..0];
-                comptime try expect(@TypeOf(slice) == *[0]u8);
-            }
-            {
-                var array = [0:0]u8{};
-                var slice = array[0..0];
-                comptime try expect(@TypeOf(slice) == *[0:0]u8);
-                try expect(slice[0] == 0);
-            }
-        }
-
-        fn testArrayAlign() !void {
-            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
-            var slice = array[4..5];
-            comptime try expect(@TypeOf(slice) == *align(4) [1]u8);
-            try expect(slice[0] == 5);
-            comptime try expect(@TypeOf(array[0..2]) == *align(4) [2]u8);
-        }
-
-        fn testPointer() !void {
-            var array = [5]u8{ 1, 2, 3, 4, 5 };
-            var pointer: [*]u8 = &array;
-            var slice = pointer[1..3];
-            comptime try expect(@TypeOf(slice) == *[2]u8);
-            try expect(slice[0] == 2);
-            try expect(slice[1] == 3);
-        }
-
-        fn testPointerZ() !void {
-            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
-            var pointer: [*:0]u8 = &array;
-            comptime try expect(@TypeOf(pointer[1..3]) == *[2]u8);
-            comptime try expect(@TypeOf(pointer[1..3 :4]) == *[2:4]u8);
-        }
-
-        fn testPointer0() !void {
-            var pointer: [*]const u0 = &[1]u0{0};
-            var slice = pointer[0..1];
-            comptime try expect(@TypeOf(slice) == *const [1]u0);
-            try expect(slice[0] == 0);
-        }
-
-        fn testPointerAlign() !void {
-            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
-            var pointer: [*]align(4) u8 = &array;
-            var slice = pointer[4..5];
-            comptime try expect(@TypeOf(slice) == *align(4) [1]u8);
-            try expect(slice[0] == 5);
-            comptime try expect(@TypeOf(pointer[0..2]) == *align(4) [2]u8);
-        }
-
-        fn testSlice() !void {
-            var array = [5]u8{ 1, 2, 3, 4, 5 };
-            var src_slice: []u8 = &array;
-            var slice = src_slice[1..3];
-            comptime try expect(@TypeOf(slice) == *[2]u8);
-            try expect(slice[0] == 2);
-            try expect(slice[1] == 3);
-        }
-
-        fn testSliceZ() !void {
-            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
-            var slice: [:0]u8 = &array;
-            comptime try expect(@TypeOf(slice[1..3]) == *[2]u8);
-            comptime try expect(@TypeOf(slice[1..]) == [:0]u8);
-            comptime try expect(@TypeOf(slice[1..3 :4]) == *[2:4]u8);
-        }
-
-        fn testSliceOpt() !void {
-            var array: [2]u8 = [2]u8{ 1, 2 };
-            var slice: ?[]u8 = &array;
-            comptime try expect(@TypeOf(&array, slice) == ?[]u8);
-            comptime try expect(@TypeOf(slice.?[0..2]) == *[2]u8);
-        }
-
-        fn testSlice0() !void {
-            {
-                var array = [0]u8{};
-                var src_slice: []u8 = &array;
-                var slice = src_slice[0..0];
-                comptime try expect(@TypeOf(slice) == *[0]u8);
-            }
-            {
-                var array = [0:0]u8{};
-                var src_slice: [:0]u8 = &array;
-                var slice = src_slice[0..0];
-                comptime try expect(@TypeOf(slice) == *[0]u8);
-            }
-        }
-
-        fn testSliceAlign() !void {
-            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
-            var src_slice: []align(4) u8 = &array;
-            var slice = src_slice[4..5];
-            comptime try expect(@TypeOf(slice) == *align(4) [1]u8);
-            try expect(slice[0] == 5);
-            comptime try expect(@TypeOf(src_slice[0..2]) == *align(4) [2]u8);
-        }
-
-        fn testConcatStrLiterals() !void {
-            try expectEqualSlices("a"[0..] ++ "b"[0..], "ab");
-            try expectEqualSlices("a"[0.. :0] ++ "b"[0.. :0], "ab");
-        }
-    };
-
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "slice of hardcoded address to pointer" {
-    const S = struct {
-        fn doTheTest() !void {
-            const pointer = @intToPtr([*]u8, 0x04)[0..2];
-            comptime try expect(@TypeOf(pointer) == *[2]u8);
-            const slice: []const u8 = pointer;
-            try expect(@ptrToInt(slice.ptr) == 4);
-            try expect(slice.len == 2);
-        }
-    };
-
-    try S.doTheTest();
-}
-
-test "type coercion of pointer to anon struct literal to pointer to slice" {
-    const S = struct {
-        const U = union {
-            a: u32,
-            b: bool,
-            c: []const u8,
-        };
-
-        fn doTheTest() !void {
-            var x1: u8 = 42;
-            const t1 = &.{ x1, 56, 54 };
-            var slice1: []const u8 = t1;
-            try expect(slice1.len == 3);
-            try expect(slice1[0] == 42);
-            try expect(slice1[1] == 56);
-            try expect(slice1[2] == 54);
-
-            var x2: []const u8 = "hello";
-            const t2 = &.{ x2, ", ", "world!" };
-            // @compileLog(@TypeOf(t2));
-            var slice2: []const []const u8 = t2;
-            try expect(slice2.len == 3);
-            try expect(mem.eql(u8, slice2[0], "hello"));
-            try expect(mem.eql(u8, slice2[1], ", "));
-            try expect(mem.eql(u8, slice2[2], "world!"));
-        }
-    };
-    // try S.doTheTest();
-    comptime try S.doTheTest();
-}
test/behavior/slice_stage1.zig
@@ -0,0 +1,334 @@
+const std = @import("std");
+const expect = std.testing.expect;
+const expectEqualSlices = std.testing.expectEqualSlices;
+const expectEqual = std.testing.expectEqual;
+const mem = std.mem;
+
+const x = @intToPtr([*]i32, 0x1000)[0..0x500];
+const y = x[0x100..];
+test "compile time slice of pointer to hard coded address" {
+    try expect(@ptrToInt(x) == 0x1000);
+    try expect(x.len == 0x500);
+
+    try expect(@ptrToInt(y) == 0x1100);
+    try expect(y.len == 0x400);
+}
+
+test "runtime safety lets us slice from len..len" {
+    var an_array = [_]u8{ 1, 2, 3 };
+    try expect(mem.eql(u8, sliceFromLenToLen(an_array[0..], 3, 3), ""));
+}
+
+fn sliceFromLenToLen(a_slice: []u8, start: usize, end: usize) []u8 {
+    return a_slice[start..end];
+}
+
+test "implicitly cast array of size 0 to slice" {
+    var msg = [_]u8{};
+    try assertLenIsZero(&msg);
+}
+
+fn assertLenIsZero(msg: []const u8) !void {
+    try expect(msg.len == 0);
+}
+
+test "C pointer" {
+    var buf: [*c]const u8 = "kjdhfkjdhfdkjhfkfjhdfkjdhfkdjhfdkjhf";
+    var len: u32 = 10;
+    var slice = buf[0..len];
+    try expectEqualSlices(u8, "kjdhfkjdhf", slice);
+}
+
+test "C pointer slice access" {
+    var buf: [10]u32 = [1]u32{42} ** 10;
+    const c_ptr = @ptrCast([*c]const u32, &buf);
+
+    var runtime_zero: usize = 0;
+    comptime try expectEqual([]const u32, @TypeOf(c_ptr[runtime_zero..1]));
+    comptime try expectEqual(*const [1]u32, @TypeOf(c_ptr[0..1]));
+
+    for (c_ptr[0..5]) |*cl| {
+        try expectEqual(@as(u32, 42), cl.*);
+    }
+}
+
+fn sliceSum(comptime q: []const u8) i32 {
+    comptime var result = 0;
+    inline for (q) |item| {
+        result += item;
+    }
+    return result;
+}
+
+test "comptime slices are disambiguated" {
+    try expect(sliceSum(&[_]u8{ 1, 2 }) == 3);
+    try expect(sliceSum(&[_]u8{ 3, 4 }) == 7);
+}
+
+test "slice type with custom alignment" {
+    const LazilyResolvedType = struct {
+        anything: i32,
+    };
+    var slice: []align(32) LazilyResolvedType = undefined;
+    var array: [10]LazilyResolvedType align(32) = undefined;
+    slice = &array;
+    slice[1].anything = 42;
+    try expect(array[1].anything == 42);
+}
+
+test "access len index of sentinel-terminated slice" {
+    const S = struct {
+        fn doTheTest() !void {
+            var slice: [:0]const u8 = "hello";
+
+            try expect(slice.len == 5);
+            try expect(slice[5] == 0);
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "obtaining a null terminated slice" {
+    // here we have a normal array
+    var buf: [50]u8 = undefined;
+
+    buf[0] = 'a';
+    buf[1] = 'b';
+    buf[2] = 'c';
+    buf[3] = 0;
+
+    // now we obtain a null terminated slice:
+    const ptr = buf[0..3 :0];
+    _ = ptr;
+
+    var runtime_len: usize = 3;
+    const ptr2 = buf[0..runtime_len :0];
+    // ptr2 is a null-terminated slice
+    comptime try expect(@TypeOf(ptr2) == [:0]u8);
+    comptime try expect(@TypeOf(ptr2[0..2]) == *[2]u8);
+    var runtime_zero: usize = 0;
+    comptime try expect(@TypeOf(ptr2[runtime_zero..2]) == []u8);
+}
+
+test "empty array to slice" {
+    const S = struct {
+        fn doTheTest() !void {
+            const empty: []align(16) u8 = &[_]u8{};
+            const align_1: []align(1) u8 = empty;
+            const align_4: []align(4) u8 = empty;
+            const align_16: []align(16) u8 = empty;
+            try expectEqual(1, @typeInfo(@TypeOf(align_1)).Pointer.alignment);
+            try expectEqual(4, @typeInfo(@TypeOf(align_4)).Pointer.alignment);
+            try expectEqual(16, @typeInfo(@TypeOf(align_16)).Pointer.alignment);
+        }
+    };
+
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "@ptrCast slice to pointer" {
+    const S = struct {
+        fn doTheTest() !void {
+            var array align(@alignOf(u16)) = [5]u8{ 0xff, 0xff, 0xff, 0xff, 0xff };
+            var slice: []u8 = &array;
+            var ptr = @ptrCast(*u16, slice);
+            try expect(ptr.* == 65535);
+        }
+    };
+
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "slice syntax resulting in pointer-to-array" {
+    const S = struct {
+        fn doTheTest() !void {
+            try testArray();
+            try testArrayZ();
+            try testArray0();
+            try testArrayAlign();
+            try testPointer();
+            try testPointerZ();
+            try testPointer0();
+            try testPointerAlign();
+            try testSlice();
+            try testSliceZ();
+            try testSlice0();
+            try testSliceOpt();
+            try testSliceAlign();
+        }
+
+        fn testArray() !void {
+            var array = [5]u8{ 1, 2, 3, 4, 5 };
+            var slice = array[1..3];
+            comptime try expect(@TypeOf(slice) == *[2]u8);
+            try expect(slice[0] == 2);
+            try expect(slice[1] == 3);
+        }
+
+        fn testArrayZ() !void {
+            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
+            comptime try expect(@TypeOf(array[1..3]) == *[2]u8);
+            comptime try expect(@TypeOf(array[1..5]) == *[4:0]u8);
+            comptime try expect(@TypeOf(array[1..]) == *[4:0]u8);
+            comptime try expect(@TypeOf(array[1..3 :4]) == *[2:4]u8);
+        }
+
+        fn testArray0() !void {
+            {
+                var array = [0]u8{};
+                var slice = array[0..0];
+                comptime try expect(@TypeOf(slice) == *[0]u8);
+            }
+            {
+                var array = [0:0]u8{};
+                var slice = array[0..0];
+                comptime try expect(@TypeOf(slice) == *[0:0]u8);
+                try expect(slice[0] == 0);
+            }
+        }
+
+        fn testArrayAlign() !void {
+            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
+            var slice = array[4..5];
+            comptime try expect(@TypeOf(slice) == *align(4) [1]u8);
+            try expect(slice[0] == 5);
+            comptime try expect(@TypeOf(array[0..2]) == *align(4) [2]u8);
+        }
+
+        fn testPointer() !void {
+            var array = [5]u8{ 1, 2, 3, 4, 5 };
+            var pointer: [*]u8 = &array;
+            var slice = pointer[1..3];
+            comptime try expect(@TypeOf(slice) == *[2]u8);
+            try expect(slice[0] == 2);
+            try expect(slice[1] == 3);
+        }
+
+        fn testPointerZ() !void {
+            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
+            var pointer: [*:0]u8 = &array;
+            comptime try expect(@TypeOf(pointer[1..3]) == *[2]u8);
+            comptime try expect(@TypeOf(pointer[1..3 :4]) == *[2:4]u8);
+        }
+
+        fn testPointer0() !void {
+            var pointer: [*]const u0 = &[1]u0{0};
+            var slice = pointer[0..1];
+            comptime try expect(@TypeOf(slice) == *const [1]u0);
+            try expect(slice[0] == 0);
+        }
+
+        fn testPointerAlign() !void {
+            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
+            var pointer: [*]align(4) u8 = &array;
+            var slice = pointer[4..5];
+            comptime try expect(@TypeOf(slice) == *align(4) [1]u8);
+            try expect(slice[0] == 5);
+            comptime try expect(@TypeOf(pointer[0..2]) == *align(4) [2]u8);
+        }
+
+        fn testSlice() !void {
+            var array = [5]u8{ 1, 2, 3, 4, 5 };
+            var src_slice: []u8 = &array;
+            var slice = src_slice[1..3];
+            comptime try expect(@TypeOf(slice) == *[2]u8);
+            try expect(slice[0] == 2);
+            try expect(slice[1] == 3);
+        }
+
+        fn testSliceZ() !void {
+            var array = [5:0]u8{ 1, 2, 3, 4, 5 };
+            var slice: [:0]u8 = &array;
+            comptime try expect(@TypeOf(slice[1..3]) == *[2]u8);
+            comptime try expect(@TypeOf(slice[1..]) == [:0]u8);
+            comptime try expect(@TypeOf(slice[1..3 :4]) == *[2:4]u8);
+        }
+
+        fn testSliceOpt() !void {
+            var array: [2]u8 = [2]u8{ 1, 2 };
+            var slice: ?[]u8 = &array;
+            comptime try expect(@TypeOf(&array, slice) == ?[]u8);
+            comptime try expect(@TypeOf(slice.?[0..2]) == *[2]u8);
+        }
+
+        fn testSlice0() !void {
+            {
+                var array = [0]u8{};
+                var src_slice: []u8 = &array;
+                var slice = src_slice[0..0];
+                comptime try expect(@TypeOf(slice) == *[0]u8);
+            }
+            {
+                var array = [0:0]u8{};
+                var src_slice: [:0]u8 = &array;
+                var slice = src_slice[0..0];
+                comptime try expect(@TypeOf(slice) == *[0]u8);
+            }
+        }
+
+        fn testSliceAlign() !void {
+            var array align(4) = [5]u8{ 1, 2, 3, 4, 5 };
+            var src_slice: []align(4) u8 = &array;
+            var slice = src_slice[4..5];
+            comptime try expect(@TypeOf(slice) == *align(4) [1]u8);
+            try expect(slice[0] == 5);
+            comptime try expect(@TypeOf(src_slice[0..2]) == *align(4) [2]u8);
+        }
+
+        fn testConcatStrLiterals() !void {
+            try expectEqualSlices("a"[0..] ++ "b"[0..], "ab");
+            try expectEqualSlices("a"[0.. :0] ++ "b"[0.. :0], "ab");
+        }
+    };
+
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "slice of hardcoded address to pointer" {
+    const S = struct {
+        fn doTheTest() !void {
+            const pointer = @intToPtr([*]u8, 0x04)[0..2];
+            comptime try expect(@TypeOf(pointer) == *[2]u8);
+            const slice: []const u8 = pointer;
+            try expect(@ptrToInt(slice.ptr) == 4);
+            try expect(slice.len == 2);
+        }
+    };
+
+    try S.doTheTest();
+}
+
+test "type coercion of pointer to anon struct literal to pointer to slice" {
+    const S = struct {
+        const U = union {
+            a: u32,
+            b: bool,
+            c: []const u8,
+        };
+
+        fn doTheTest() !void {
+            var x1: u8 = 42;
+            const t1 = &.{ x1, 56, 54 };
+            var slice1: []const u8 = t1;
+            try expect(slice1.len == 3);
+            try expect(slice1[0] == 42);
+            try expect(slice1[1] == 56);
+            try expect(slice1[2] == 54);
+
+            var x2: []const u8 = "hello";
+            const t2 = &.{ x2, ", ", "world!" };
+            // @compileLog(@TypeOf(t2));
+            var slice2: []const []const u8 = t2;
+            try expect(slice2.len == 3);
+            try expect(mem.eql(u8, slice2[0], "hello"));
+            try expect(mem.eql(u8, slice2[1], ", "));
+            try expect(mem.eql(u8, slice2[2], "world!"));
+        }
+    };
+    // try S.doTheTest();
+    comptime try S.doTheTest();
+}
test/behavior.zig
@@ -26,6 +26,7 @@ test {
     _ = @import("behavior/math.zig");
     _ = @import("behavior/member_func.zig");
     _ = @import("behavior/pointers.zig");
+    _ = @import("behavior/slice.zig");
     _ = @import("behavior/sizeof_and_typeof.zig");
     _ = @import("behavior/struct.zig");
     _ = @import("behavior/switch.zig");
@@ -150,7 +151,7 @@ test {
         _ = @import("behavior/shuffle.zig");
         _ = @import("behavior/select.zig");
         _ = @import("behavior/sizeof_and_typeof_stage1.zig");
-        _ = @import("behavior/slice.zig");
+        _ = @import("behavior/slice_stage1.zig");
         _ = @import("behavior/slice_sentinel_comptime.zig");
         _ = @import("behavior/struct_stage1.zig");
         _ = @import("behavior/struct_contains_null_ptr_itself.zig");