stage2: progress towards ability to compile compiler-rt

 * prepare compiler-rt to support being compiled by stage2
   - put in a few minor workarounds that will be removed later, such as
     using `builtin.stage2_arch` rather than `builtin.cpu.arch`.
   - only try to export a few symbols for now - we'll move more symbols
     over to the "working in stage2" section as they become functional
     and gain test coverage.
   - use `inline fn` at function declarations rather than `@call` with an
     always_inline modifier at the callsites, to avoid depending on the
     anonymous array literal syntax language feature (for now).
 * AIR: replace floatcast instruction with fptrunc and fpext for
   shortening and widening floating point values, respectively.
 * Introduce a new ZIR instruction, `export_value`, which implements
   `@export` for the case when the thing to be exported is a local
   comptime value that points to a function.
   - AstGen: fix `@export` not properly reporting ambiguous decl
     references.
 * Sema: handle ExportOptions linkage. The value is now available to all
   backends.
   - Implement setting global linkage as appropriate in the LLVM
     backend. I did not yet inspect the LLVM IR, so this still needs to
     be audited. There is already a pending task to make sure the alias
     stuff is working as intended, and this is related.
   - Sema almost handles section, just a tiny bit more code is needed in
     `resolveExportOptions`.
 * Sema: implement float widening and shortening for both `@floatCast`
   and float coercion.
   - Implement the LLVM backend code for this as well.

5 files changed, 844 insertions, 849 deletions

diff --git a/test/behavior.zig b/test/behavior.zig
index f328db968e..7fbba99a8c 100644
--- a/test/behavior.zig
+++ b/test/behavior.zig
@@ -13,6 +13,7 @@ test {
     _ = @import("behavior/atomics.zig");
     _ = @import("behavior/sizeof_and_typeof.zig");
     _ = @import("behavior/translate_c_macros.zig");
+    _ = @import("behavior/union.zig");
     _ = @import("behavior/widening.zig");
 
     if (builtin.zig_is_stage2) {
@@ -149,7 +150,7 @@ test {
         _ = @import("behavior/typename.zig");
         _ = @import("behavior/undefined.zig");
         _ = @import("behavior/underscore.zig");
-        _ = @import("behavior/union.zig");
+        _ = @import("behavior/union_stage1.zig");
         _ = @import("behavior/usingnamespace_stage1.zig");
         _ = @import("behavior/var_args.zig");
         _ = @import("behavior/vector.zig");
@@ -158,7 +159,6 @@ test {
             _ = @import("behavior/wasm.zig");
         }
         _ = @import("behavior/while.zig");
-        _ = @import("behavior/widening_stage1.zig");
         _ = @import("behavior/src.zig");
         _ = @import("behavior/translate_c_macros_stage1.zig");
     }
diff --git a/test/behavior/union.zig b/test/behavior/union.zig
index 323dd18f4d..14b5e374dd 100644
--- a/test/behavior/union.zig
+++ b/test/behavior/union.zig
@@ -2,816 +2,3 @@ const std = @import("std");
 const expect = std.testing.expect;
 const expectEqual = std.testing.expectEqual;
 const Tag = std.meta.Tag;
-
-const Value = union(enum) {
-    Int: u64,
-    Array: [9]u8,
-};
-
-const Agg = struct {
-    val1: Value,
-    val2: Value,
-};
-
-const v1 = Value{ .Int = 1234 };
-const v2 = Value{ .Array = [_]u8{3} ** 9 };
-
-const err = @as(anyerror!Agg, Agg{
-    .val1 = v1,
-    .val2 = v2,
-});
-
-const array = [_]Value{
-    v1,
-    v2,
-    v1,
-    v2,
-};
-
-test "unions embedded in aggregate types" {
-    switch (array[1]) {
-        Value.Array => |arr| try expect(arr[4] == 3),
-        else => unreachable,
-    }
-    switch ((err catch unreachable).val1) {
-        Value.Int => |x| try expect(x == 1234),
-        else => unreachable,
-    }
-}
-
-const Foo = union {
-    float: f64,
-    int: i32,
-};
-
-test "basic unions" {
-    var foo = Foo{ .int = 1 };
-    try expect(foo.int == 1);
-    foo = Foo{ .float = 12.34 };
-    try expect(foo.float == 12.34);
-}
-
-test "comptime union field access" {
-    comptime {
-        var foo = Foo{ .int = 0 };
-        try expect(foo.int == 0);
-
-        foo = Foo{ .float = 42.42 };
-        try expect(foo.float == 42.42);
-    }
-}
-
-test "init union with runtime value" {
-    var foo: Foo = undefined;
-
-    setFloat(&foo, 12.34);
-    try expect(foo.float == 12.34);
-
-    setInt(&foo, 42);
-    try expect(foo.int == 42);
-}
-
-fn setFloat(foo: *Foo, x: f64) void {
-    foo.* = Foo{ .float = x };
-}
-
-fn setInt(foo: *Foo, x: i32) void {
-    foo.* = Foo{ .int = x };
-}
-
-const FooExtern = extern union {
-    float: f64,
-    int: i32,
-};
-
-test "basic extern unions" {
-    var foo = FooExtern{ .int = 1 };
-    try expect(foo.int == 1);
-    foo.float = 12.34;
-    try expect(foo.float == 12.34);
-}
-
-const Letter = enum {
-    A,
-    B,
-    C,
-};
-const Payload = union(Letter) {
-    A: i32,
-    B: f64,
-    C: bool,
-};
-
-test "union with specified enum tag" {
-    try doTest();
-    comptime try doTest();
-}
-
-fn doTest() error{TestUnexpectedResult}!void {
-    try expect((try bar(Payload{ .A = 1234 })) == -10);
-}
-
-fn bar(value: Payload) error{TestUnexpectedResult}!i32 {
-    try expect(@as(Letter, value) == Letter.A);
-    return switch (value) {
-        Payload.A => |x| return x - 1244,
-        Payload.B => |x| if (x == 12.34) @as(i32, 20) else 21,
-        Payload.C => |x| if (x) @as(i32, 30) else 31,
-    };
-}
-
-const MultipleChoice = union(enum(u32)) {
-    A = 20,
-    B = 40,
-    C = 60,
-    D = 1000,
-};
-test "simple union(enum(u32))" {
-    var x = MultipleChoice.C;
-    try expect(x == MultipleChoice.C);
-    try expect(@enumToInt(@as(Tag(MultipleChoice), x)) == 60);
-}
-
-const MultipleChoice2 = union(enum(u32)) {
-    Unspecified1: i32,
-    A: f32 = 20,
-    Unspecified2: void,
-    B: bool = 40,
-    Unspecified3: i32,
-    C: i8 = 60,
-    Unspecified4: void,
-    D: void = 1000,
-    Unspecified5: i32,
-};
-
-test "union(enum(u32)) with specified and unspecified tag values" {
-    comptime try expect(Tag(Tag(MultipleChoice2)) == u32);
-    try testEnumWithSpecifiedAndUnspecifiedTagValues(MultipleChoice2{ .C = 123 });
-    comptime try testEnumWithSpecifiedAndUnspecifiedTagValues(MultipleChoice2{ .C = 123 });
-}
-
-fn testEnumWithSpecifiedAndUnspecifiedTagValues(x: MultipleChoice2) !void {
-    try expect(@enumToInt(@as(Tag(MultipleChoice2), x)) == 60);
-    try expect(1123 == switch (x) {
-        MultipleChoice2.A => 1,
-        MultipleChoice2.B => 2,
-        MultipleChoice2.C => |v| @as(i32, 1000) + v,
-        MultipleChoice2.D => 4,
-        MultipleChoice2.Unspecified1 => 5,
-        MultipleChoice2.Unspecified2 => 6,
-        MultipleChoice2.Unspecified3 => 7,
-        MultipleChoice2.Unspecified4 => 8,
-        MultipleChoice2.Unspecified5 => 9,
-    });
-}
-
-const ExternPtrOrInt = extern union {
-    ptr: *u8,
-    int: u64,
-};
-test "extern union size" {
-    comptime try expect(@sizeOf(ExternPtrOrInt) == 8);
-}
-
-const PackedPtrOrInt = packed union {
-    ptr: *u8,
-    int: u64,
-};
-test "extern union size" {
-    comptime try expect(@sizeOf(PackedPtrOrInt) == 8);
-}
-
-const ZeroBits = union {
-    OnlyField: void,
-};
-test "union with only 1 field which is void should be zero bits" {
-    comptime try expect(@sizeOf(ZeroBits) == 0);
-}
-
-const TheTag = enum {
-    A,
-    B,
-    C,
-};
-const TheUnion = union(TheTag) {
-    A: i32,
-    B: i32,
-    C: i32,
-};
-test "union field access gives the enum values" {
-    try expect(TheUnion.A == TheTag.A);
-    try expect(TheUnion.B == TheTag.B);
-    try expect(TheUnion.C == TheTag.C);
-}
-
-test "cast union to tag type of union" {
-    try testCastUnionToTag(TheUnion{ .B = 1234 });
-    comptime try testCastUnionToTag(TheUnion{ .B = 1234 });
-}
-
-fn testCastUnionToTag(x: TheUnion) !void {
-    try expect(@as(TheTag, x) == TheTag.B);
-}
-
-test "cast tag type of union to union" {
-    var x: Value2 = Letter2.B;
-    try expect(@as(Letter2, x) == Letter2.B);
-}
-const Letter2 = enum {
-    A,
-    B,
-    C,
-};
-const Value2 = union(Letter2) {
-    A: i32,
-    B,
-    C,
-};
-
-test "implicit cast union to its tag type" {
-    var x: Value2 = Letter2.B;
-    try expect(x == Letter2.B);
-    try giveMeLetterB(x);
-}
-fn giveMeLetterB(x: Letter2) !void {
-    try expect(x == Value2.B);
-}
-
-pub const PackThis = union(enum) {
-    Invalid: bool,
-    StringLiteral: u2,
-};
-
-test "constant packed union" {
-    try testConstPackedUnion(&[_]PackThis{PackThis{ .StringLiteral = 1 }});
-}
-
-fn testConstPackedUnion(expected_tokens: []const PackThis) !void {
-    try expect(expected_tokens[0].StringLiteral == 1);
-}
-
-test "switch on union with only 1 field" {
-    var r: PartialInst = undefined;
-    r = PartialInst.Compiled;
-    switch (r) {
-        PartialInst.Compiled => {
-            var z: PartialInstWithPayload = undefined;
-            z = PartialInstWithPayload{ .Compiled = 1234 };
-            switch (z) {
-                PartialInstWithPayload.Compiled => |x| {
-                    try expect(x == 1234);
-                    return;
-                },
-            }
-        },
-    }
-    unreachable;
-}
-
-const PartialInst = union(enum) {
-    Compiled,
-};
-
-const PartialInstWithPayload = union(enum) {
-    Compiled: i32,
-};
-
-test "access a member of tagged union with conflicting enum tag name" {
-    const Bar = union(enum) {
-        A: A,
-        B: B,
-
-        const A = u8;
-        const B = void;
-    };
-
-    comptime try expect(Bar.A == u8);
-}
-
-test "tagged union initialization with runtime void" {
-    try expect(testTaggedUnionInit({}));
-}
-
-const TaggedUnionWithAVoid = union(enum) {
-    A,
-    B: i32,
-};
-
-fn testTaggedUnionInit(x: anytype) bool {
-    const y = TaggedUnionWithAVoid{ .A = x };
-    return @as(Tag(TaggedUnionWithAVoid), y) == TaggedUnionWithAVoid.A;
-}
-
-pub const UnionEnumNoPayloads = union(enum) {
-    A,
-    B,
-};
-
-test "tagged union with no payloads" {
-    const a = UnionEnumNoPayloads{ .B = {} };
-    switch (a) {
-        Tag(UnionEnumNoPayloads).A => @panic("wrong"),
-        Tag(UnionEnumNoPayloads).B => {},
-    }
-}
-
-test "union with only 1 field casted to its enum type" {
-    const Literal = union(enum) {
-        Number: f64,
-        Bool: bool,
-    };
-
-    const Expr = union(enum) {
-        Literal: Literal,
-    };
-
-    var e = Expr{ .Literal = Literal{ .Bool = true } };
-    const ExprTag = Tag(Expr);
-    comptime try expect(Tag(ExprTag) == u0);
-    var t = @as(ExprTag, e);
-    try expect(t == Expr.Literal);
-}
-
-test "union with only 1 field casted to its enum type which has enum value specified" {
-    const Literal = union(enum) {
-        Number: f64,
-        Bool: bool,
-    };
-
-    const ExprTag = enum(comptime_int) {
-        Literal = 33,
-    };
-
-    const Expr = union(ExprTag) {
-        Literal: Literal,
-    };
-
-    var e = Expr{ .Literal = Literal{ .Bool = true } };
-    comptime try expect(Tag(ExprTag) == comptime_int);
-    var t = @as(ExprTag, e);
-    try expect(t == Expr.Literal);
-    try expect(@enumToInt(t) == 33);
-    comptime try expect(@enumToInt(t) == 33);
-}
-
-test "@enumToInt works on unions" {
-    const Bar = union(enum) {
-        A: bool,
-        B: u8,
-        C,
-    };
-
-    const a = Bar{ .A = true };
-    var b = Bar{ .B = undefined };
-    var c = Bar.C;
-    try expect(@enumToInt(a) == 0);
-    try expect(@enumToInt(b) == 1);
-    try expect(@enumToInt(c) == 2);
-}
-
-const Attribute = union(enum) {
-    A: bool,
-    B: u8,
-};
-
-fn setAttribute(attr: Attribute) void {
-    _ = attr;
-}
-
-fn Setter(attr: Attribute) type {
-    return struct {
-        fn set() void {
-            setAttribute(attr);
-        }
-    };
-}
-
-test "comptime union field value equality" {
-    const a0 = Setter(Attribute{ .A = false });
-    const a1 = Setter(Attribute{ .A = true });
-    const a2 = Setter(Attribute{ .A = false });
-
-    const b0 = Setter(Attribute{ .B = 5 });
-    const b1 = Setter(Attribute{ .B = 9 });
-    const b2 = Setter(Attribute{ .B = 5 });
-
-    try expect(a0 == a0);
-    try expect(a1 == a1);
-    try expect(a0 == a2);
-
-    try expect(b0 == b0);
-    try expect(b1 == b1);
-    try expect(b0 == b2);
-
-    try expect(a0 != b0);
-    try expect(a0 != a1);
-    try expect(b0 != b1);
-}
-
-test "return union init with void payload" {
-    const S = struct {
-        fn entry() !void {
-            try expect(func().state == State.one);
-        }
-        const Outer = union(enum) {
-            state: State,
-        };
-        const State = union(enum) {
-            one: void,
-            two: u32,
-        };
-        fn func() Outer {
-            return Outer{ .state = State{ .one = {} } };
-        }
-    };
-    try S.entry();
-    comptime try S.entry();
-}
-
-test "@unionInit can modify a union type" {
-    const UnionInitEnum = union(enum) {
-        Boolean: bool,
-        Byte: u8,
-    };
-
-    var value: UnionInitEnum = undefined;
-
-    value = @unionInit(UnionInitEnum, "Boolean", true);
-    try expect(value.Boolean == true);
-    value.Boolean = false;
-    try expect(value.Boolean == false);
-
-    value = @unionInit(UnionInitEnum, "Byte", 2);
-    try expect(value.Byte == 2);
-    value.Byte = 3;
-    try expect(value.Byte == 3);
-}
-
-test "@unionInit can modify a pointer value" {
-    const UnionInitEnum = union(enum) {
-        Boolean: bool,
-        Byte: u8,
-    };
-
-    var value: UnionInitEnum = undefined;
-    var value_ptr = &value;
-
-    value_ptr.* = @unionInit(UnionInitEnum, "Boolean", true);
-    try expect(value.Boolean == true);
-
-    value_ptr.* = @unionInit(UnionInitEnum, "Byte", 2);
-    try expect(value.Byte == 2);
-}
-
-test "union no tag with struct member" {
-    const Struct = struct {};
-    const Union = union {
-        s: Struct,
-        pub fn foo(self: *@This()) void {
-            _ = self;
-        }
-    };
-    var u = Union{ .s = Struct{} };
-    u.foo();
-}
-
-fn testComparison() !void {
-    var x = Payload{ .A = 42 };
-    try expect(x == .A);
-    try expect(x != .B);
-    try expect(x != .C);
-    try expect((x == .B) == false);
-    try expect((x == .C) == false);
-    try expect((x != .A) == false);
-}
-
-test "comparison between union and enum literal" {
-    try testComparison();
-    comptime try testComparison();
-}
-
-test "packed union generates correctly aligned LLVM type" {
-    const U = packed union {
-        f1: fn () error{TestUnexpectedResult}!void,
-        f2: u32,
-    };
-    var foo = [_]U{
-        U{ .f1 = doTest },
-        U{ .f2 = 0 },
-    };
-    try foo[0].f1();
-}
-
-test "union with one member defaults to u0 tag type" {
-    const U0 = union(enum) {
-        X: u32,
-    };
-    comptime try expect(Tag(Tag(U0)) == u0);
-}
-
-test "union with comptime_int tag" {
-    const Union = union(enum(comptime_int)) {
-        X: u32,
-        Y: u16,
-        Z: u8,
-    };
-    comptime try expect(Tag(Tag(Union)) == comptime_int);
-}
-
-test "extern union doesn't trigger field check at comptime" {
-    const U = extern union {
-        x: u32,
-        y: u8,
-    };
-
-    const x = U{ .x = 0x55AAAA55 };
-    comptime try expect(x.y == 0x55);
-}
-
-const Foo1 = union(enum) {
-    f: struct {
-        x: usize,
-    },
-};
-var glbl: Foo1 = undefined;
-
-test "global union with single field is correctly initialized" {
-    glbl = Foo1{
-        .f = @typeInfo(Foo1).Union.fields[0].field_type{ .x = 123 },
-    };
-    try expect(glbl.f.x == 123);
-}
-
-pub const FooUnion = union(enum) {
-    U0: usize,
-    U1: u8,
-};
-
-var glbl_array: [2]FooUnion = undefined;
-
-test "initialize global array of union" {
-    glbl_array[1] = FooUnion{ .U1 = 2 };
-    glbl_array[0] = FooUnion{ .U0 = 1 };
-    try expect(glbl_array[0].U0 == 1);
-    try expect(glbl_array[1].U1 == 2);
-}
-
-test "anonymous union literal syntax" {
-    const S = struct {
-        const Number = union {
-            int: i32,
-            float: f64,
-        };
-
-        fn doTheTest() !void {
-            var i: Number = .{ .int = 42 };
-            var f = makeNumber();
-            try expect(i.int == 42);
-            try expect(f.float == 12.34);
-        }
-
-        fn makeNumber() Number {
-            return .{ .float = 12.34 };
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "update the tag value for zero-sized unions" {
-    const S = union(enum) {
-        U0: void,
-        U1: void,
-    };
-    var x = S{ .U0 = {} };
-    try expect(x == .U0);
-    x = S{ .U1 = {} };
-    try expect(x == .U1);
-}
-
-test "function call result coerces from tagged union to the tag" {
-    const S = struct {
-        const Arch = union(enum) {
-            One,
-            Two: usize,
-        };
-
-        const ArchTag = Tag(Arch);
-
-        fn doTheTest() !void {
-            var x: ArchTag = getArch1();
-            try expect(x == .One);
-
-            var y: ArchTag = getArch2();
-            try expect(y == .Two);
-        }
-
-        pub fn getArch1() Arch {
-            return .One;
-        }
-
-        pub fn getArch2() Arch {
-            return .{ .Two = 99 };
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "0-sized extern union definition" {
-    const U = extern union {
-        a: void,
-        const f = 1;
-    };
-
-    try expect(U.f == 1);
-}
-
-test "union initializer generates padding only if needed" {
-    const U = union(enum) {
-        A: u24,
-    };
-
-    var v = U{ .A = 532 };
-    try expect(v.A == 532);
-}
-
-test "runtime tag name with single field" {
-    const U = union(enum) {
-        A: i32,
-    };
-
-    var v = U{ .A = 42 };
-    try expect(std.mem.eql(u8, @tagName(v), "A"));
-}
-
-test "cast from anonymous struct to union" {
-    const S = struct {
-        const U = union(enum) {
-            A: u32,
-            B: []const u8,
-            C: void,
-        };
-        fn doTheTest() !void {
-            var y: u32 = 42;
-            const t0 = .{ .A = 123 };
-            const t1 = .{ .B = "foo" };
-            const t2 = .{ .C = {} };
-            const t3 = .{ .A = y };
-            const x0: U = t0;
-            var x1: U = t1;
-            const x2: U = t2;
-            var x3: U = t3;
-            try expect(x0.A == 123);
-            try expect(std.mem.eql(u8, x1.B, "foo"));
-            try expect(x2 == .C);
-            try expect(x3.A == y);
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "cast from pointer to anonymous struct to pointer to union" {
-    const S = struct {
-        const U = union(enum) {
-            A: u32,
-            B: []const u8,
-            C: void,
-        };
-        fn doTheTest() !void {
-            var y: u32 = 42;
-            const t0 = &.{ .A = 123 };
-            const t1 = &.{ .B = "foo" };
-            const t2 = &.{ .C = {} };
-            const t3 = &.{ .A = y };
-            const x0: *const U = t0;
-            var x1: *const U = t1;
-            const x2: *const U = t2;
-            var x3: *const U = t3;
-            try expect(x0.A == 123);
-            try expect(std.mem.eql(u8, x1.B, "foo"));
-            try expect(x2.* == .C);
-            try expect(x3.A == y);
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "method call on an empty union" {
-    const S = struct {
-        const MyUnion = union(MyUnionTag) {
-            pub const MyUnionTag = enum { X1, X2 };
-            X1: [0]u8,
-            X2: [0]u8,
-
-            pub fn useIt(self: *@This()) bool {
-                _ = self;
-                return true;
-            }
-        };
-
-        fn doTheTest() !void {
-            var u = MyUnion{ .X1 = [0]u8{} };
-            try expect(u.useIt());
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "switching on non exhaustive union" {
-    const S = struct {
-        const E = enum(u8) {
-            a,
-            b,
-            _,
-        };
-        const U = union(E) {
-            a: i32,
-            b: u32,
-        };
-        fn doTheTest() !void {
-            var a = U{ .a = 2 };
-            switch (a) {
-                .a => |val| try expect(val == 2),
-                .b => unreachable,
-            }
-        }
-    };
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "containers with single-field enums" {
-    const S = struct {
-        const A = union(enum) { f1 };
-        const B = union(enum) { f1: void };
-        const C = struct { a: A };
-        const D = struct { a: B };
-
-        fn doTheTest() !void {
-            var array1 = [1]A{A{ .f1 = {} }};
-            var array2 = [1]B{B{ .f1 = {} }};
-            try expect(array1[0] == .f1);
-            try expect(array2[0] == .f1);
-
-            var struct1 = C{ .a = A{ .f1 = {} } };
-            var struct2 = D{ .a = B{ .f1 = {} } };
-            try expect(struct1.a == .f1);
-            try expect(struct2.a == .f1);
-        }
-    };
-
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "@unionInit on union w/ tag but no fields" {
-    const S = struct {
-        const Type = enum(u8) { no_op = 105 };
-
-        const Data = union(Type) {
-            no_op: void,
-
-            pub fn decode(buf: []const u8) Data {
-                _ = buf;
-                return @unionInit(Data, "no_op", {});
-            }
-        };
-
-        comptime {
-            std.debug.assert(@sizeOf(Data) != 0);
-        }
-
-        fn doTheTest() !void {
-            var data: Data = .{ .no_op = .{} };
-            _ = data;
-            var o = Data.decode(&[_]u8{});
-            try expectEqual(Type.no_op, o);
-        }
-    };
-
-    try S.doTheTest();
-    comptime try S.doTheTest();
-}
-
-test "union enum type gets a separate scope" {
-    const S = struct {
-        const U = union(enum) {
-            a: u8,
-            const foo = 1;
-        };
-
-        fn doTheTest() !void {
-            try expect(!@hasDecl(Tag(U), "foo"));
-        }
-    };
-
-    try S.doTheTest();
-}
-test "anytype union field: issue #9233" {
-    const Baz = union(enum) { bar: anytype };
-    _ = Baz;
-}
diff --git a/test/behavior/union_stage1.zig b/test/behavior/union_stage1.zig
new file mode 100644
index 0000000000..086bd981cd
--- /dev/null
+++ b/test/behavior/union_stage1.zig
@@ -0,0 +1,799 @@
+const std = @import("std");
+const expect = std.testing.expect;
+const expectEqual = std.testing.expectEqual;
+const Tag = std.meta.Tag;
+
+const Value = union(enum) {
+    Int: u64,
+    Array: [9]u8,
+};
+
+const Agg = struct {
+    val1: Value,
+    val2: Value,
+};
+
+const v1 = Value{ .Int = 1234 };
+const v2 = Value{ .Array = [_]u8{3} ** 9 };
+
+const err = @as(anyerror!Agg, Agg{
+    .val1 = v1,
+    .val2 = v2,
+});
+
+const array = [_]Value{ v1, v2, v1, v2 };
+
+test "unions embedded in aggregate types" {
+    switch (array[1]) {
+        Value.Array => |arr| try expect(arr[4] == 3),
+        else => unreachable,
+    }
+    switch ((err catch unreachable).val1) {
+        Value.Int => |x| try expect(x == 1234),
+        else => unreachable,
+    }
+}
+
+const Foo = union {
+    float: f64,
+    int: i32,
+};
+
+test "basic unions" {
+    var foo = Foo{ .int = 1 };
+    try expect(foo.int == 1);
+    foo = Foo{ .float = 12.34 };
+    try expect(foo.float == 12.34);
+}
+
+test "comptime union field access" {
+    comptime {
+        var foo = Foo{ .int = 0 };
+        try expect(foo.int == 0);
+
+        foo = Foo{ .float = 42.42 };
+        try expect(foo.float == 42.42);
+    }
+}
+
+test "init union with runtime value" {
+    var foo: Foo = undefined;
+
+    setFloat(&foo, 12.34);
+    try expect(foo.float == 12.34);
+
+    setInt(&foo, 42);
+    try expect(foo.int == 42);
+}
+
+fn setFloat(foo: *Foo, x: f64) void {
+    foo.* = Foo{ .float = x };
+}
+
+fn setInt(foo: *Foo, x: i32) void {
+    foo.* = Foo{ .int = x };
+}
+
+const FooExtern = extern union {
+    float: f64,
+    int: i32,
+};
+
+test "basic extern unions" {
+    var foo = FooExtern{ .int = 1 };
+    try expect(foo.int == 1);
+    foo.float = 12.34;
+    try expect(foo.float == 12.34);
+}
+
+const Letter = enum { A, B, C };
+const Payload = union(Letter) {
+    A: i32,
+    B: f64,
+    C: bool,
+};
+
+test "union with specified enum tag" {
+    try doTest();
+    comptime try doTest();
+}
+
+fn doTest() error{TestUnexpectedResult}!void {
+    try expect((try bar(Payload{ .A = 1234 })) == -10);
+}
+
+fn bar(value: Payload) error{TestUnexpectedResult}!i32 {
+    try expect(@as(Letter, value) == Letter.A);
+    return switch (value) {
+        Payload.A => |x| return x - 1244,
+        Payload.B => |x| if (x == 12.34) @as(i32, 20) else 21,
+        Payload.C => |x| if (x) @as(i32, 30) else 31,
+    };
+}
+
+const MultipleChoice = union(enum(u32)) {
+    A = 20,
+    B = 40,
+    C = 60,
+    D = 1000,
+};
+test "simple union(enum(u32))" {
+    var x = MultipleChoice.C;
+    try expect(x == MultipleChoice.C);
+    try expect(@enumToInt(@as(Tag(MultipleChoice), x)) == 60);
+}
+
+const MultipleChoice2 = union(enum(u32)) {
+    Unspecified1: i32,
+    A: f32 = 20,
+    Unspecified2: void,
+    B: bool = 40,
+    Unspecified3: i32,
+    C: i8 = 60,
+    Unspecified4: void,
+    D: void = 1000,
+    Unspecified5: i32,
+};
+
+test "union(enum(u32)) with specified and unspecified tag values" {
+    comptime try expect(Tag(Tag(MultipleChoice2)) == u32);
+    try testEnumWithSpecifiedAndUnspecifiedTagValues(MultipleChoice2{ .C = 123 });
+    comptime try testEnumWithSpecifiedAndUnspecifiedTagValues(MultipleChoice2{ .C = 123 });
+}
+
+fn testEnumWithSpecifiedAndUnspecifiedTagValues(x: MultipleChoice2) !void {
+    try expect(@enumToInt(@as(Tag(MultipleChoice2), x)) == 60);
+    try expect(1123 == switch (x) {
+        MultipleChoice2.A => 1,
+        MultipleChoice2.B => 2,
+        MultipleChoice2.C => |v| @as(i32, 1000) + v,
+        MultipleChoice2.D => 4,
+        MultipleChoice2.Unspecified1 => 5,
+        MultipleChoice2.Unspecified2 => 6,
+        MultipleChoice2.Unspecified3 => 7,
+        MultipleChoice2.Unspecified4 => 8,
+        MultipleChoice2.Unspecified5 => 9,
+    });
+}
+
+const ExternPtrOrInt = extern union {
+    ptr: *u8,
+    int: u64,
+};
+test "extern union size" {
+    comptime try expect(@sizeOf(ExternPtrOrInt) == 8);
+}
+
+const PackedPtrOrInt = packed union {
+    ptr: *u8,
+    int: u64,
+};
+test "extern union size" {
+    comptime try expect(@sizeOf(PackedPtrOrInt) == 8);
+}
+
+const ZeroBits = union {
+    OnlyField: void,
+};
+test "union with only 1 field which is void should be zero bits" {
+    comptime try expect(@sizeOf(ZeroBits) == 0);
+}
+
+const TheTag = enum { A, B, C };
+const TheUnion = union(TheTag) {
+    A: i32,
+    B: i32,
+    C: i32,
+};
+test "union field access gives the enum values" {
+    try expect(TheUnion.A == TheTag.A);
+    try expect(TheUnion.B == TheTag.B);
+    try expect(TheUnion.C == TheTag.C);
+}
+
+test "cast union to tag type of union" {
+    try testCastUnionToTag(TheUnion{ .B = 1234 });
+    comptime try testCastUnionToTag(TheUnion{ .B = 1234 });
+}
+
+fn testCastUnionToTag(x: TheUnion) !void {
+    try expect(@as(TheTag, x) == TheTag.B);
+}
+
+test "cast tag type of union to union" {
+    var x: Value2 = Letter2.B;
+    try expect(@as(Letter2, x) == Letter2.B);
+}
+const Letter2 = enum { A, B, C };
+const Value2 = union(Letter2) {
+    A: i32,
+    B,
+    C,
+};
+
+test "implicit cast union to its tag type" {
+    var x: Value2 = Letter2.B;
+    try expect(x == Letter2.B);
+    try giveMeLetterB(x);
+}
+fn giveMeLetterB(x: Letter2) !void {
+    try expect(x == Value2.B);
+}
+
+// TODO it looks like this test intended to test packed unions, but this is not a packed
+// union. go through git history and find out what happened.
+pub const PackThis = union(enum) {
+    Invalid: bool,
+    StringLiteral: u2,
+};
+
+test "constant packed union" {
+    try testConstPackedUnion(&[_]PackThis{PackThis{ .StringLiteral = 1 }});
+}
+
+fn testConstPackedUnion(expected_tokens: []const PackThis) !void {
+    try expect(expected_tokens[0].StringLiteral == 1);
+}
+
+test "switch on union with only 1 field" {
+    var r: PartialInst = undefined;
+    r = PartialInst.Compiled;
+    switch (r) {
+        PartialInst.Compiled => {
+            var z: PartialInstWithPayload = undefined;
+            z = PartialInstWithPayload{ .Compiled = 1234 };
+            switch (z) {
+                PartialInstWithPayload.Compiled => |x| {
+                    try expect(x == 1234);
+                    return;
+                },
+            }
+        },
+    }
+    unreachable;
+}
+
+const PartialInst = union(enum) {
+    Compiled,
+};
+
+const PartialInstWithPayload = union(enum) {
+    Compiled: i32,
+};
+
+test "access a member of tagged union with conflicting enum tag name" {
+    const Bar = union(enum) {
+        A: A,
+        B: B,
+
+        const A = u8;
+        const B = void;
+    };
+
+    comptime try expect(Bar.A == u8);
+}
+
+test "tagged union initialization with runtime void" {
+    try expect(testTaggedUnionInit({}));
+}
+
+const TaggedUnionWithAVoid = union(enum) {
+    A,
+    B: i32,
+};
+
+fn testTaggedUnionInit(x: anytype) bool {
+    const y = TaggedUnionWithAVoid{ .A = x };
+    return @as(Tag(TaggedUnionWithAVoid), y) == TaggedUnionWithAVoid.A;
+}
+
+pub const UnionEnumNoPayloads = union(enum) { A, B };
+
+test "tagged union with no payloads" {
+    const a = UnionEnumNoPayloads{ .B = {} };
+    switch (a) {
+        Tag(UnionEnumNoPayloads).A => @panic("wrong"),
+        Tag(UnionEnumNoPayloads).B => {},
+    }
+}
+
+test "union with only 1 field casted to its enum type" {
+    const Literal = union(enum) {
+        Number: f64,
+        Bool: bool,
+    };
+
+    const Expr = union(enum) {
+        Literal: Literal,
+    };
+
+    var e = Expr{ .Literal = Literal{ .Bool = true } };
+    const ExprTag = Tag(Expr);
+    comptime try expect(Tag(ExprTag) == u0);
+    var t = @as(ExprTag, e);
+    try expect(t == Expr.Literal);
+}
+
+test "union with only 1 field casted to its enum type which has enum value specified" {
+    const Literal = union(enum) {
+        Number: f64,
+        Bool: bool,
+    };
+
+    const ExprTag = enum(comptime_int) {
+        Literal = 33,
+    };
+
+    const Expr = union(ExprTag) {
+        Literal: Literal,
+    };
+
+    var e = Expr{ .Literal = Literal{ .Bool = true } };
+    comptime try expect(Tag(ExprTag) == comptime_int);
+    var t = @as(ExprTag, e);
+    try expect(t == Expr.Literal);
+    try expect(@enumToInt(t) == 33);
+    comptime try expect(@enumToInt(t) == 33);
+}
+
+test "@enumToInt works on unions" {
+    const Bar = union(enum) {
+        A: bool,
+        B: u8,
+        C,
+    };
+
+    const a = Bar{ .A = true };
+    var b = Bar{ .B = undefined };
+    var c = Bar.C;
+    try expect(@enumToInt(a) == 0);
+    try expect(@enumToInt(b) == 1);
+    try expect(@enumToInt(c) == 2);
+}
+
+const Attribute = union(enum) {
+    A: bool,
+    B: u8,
+};
+
+fn setAttribute(attr: Attribute) void {
+    _ = attr;
+}
+
+fn Setter(attr: Attribute) type {
+    return struct {
+        fn set() void {
+            setAttribute(attr);
+        }
+    };
+}
+
+test "comptime union field value equality" {
+    const a0 = Setter(Attribute{ .A = false });
+    const a1 = Setter(Attribute{ .A = true });
+    const a2 = Setter(Attribute{ .A = false });
+
+    const b0 = Setter(Attribute{ .B = 5 });
+    const b1 = Setter(Attribute{ .B = 9 });
+    const b2 = Setter(Attribute{ .B = 5 });
+
+    try expect(a0 == a0);
+    try expect(a1 == a1);
+    try expect(a0 == a2);
+
+    try expect(b0 == b0);
+    try expect(b1 == b1);
+    try expect(b0 == b2);
+
+    try expect(a0 != b0);
+    try expect(a0 != a1);
+    try expect(b0 != b1);
+}
+
+test "return union init with void payload" {
+    const S = struct {
+        fn entry() !void {
+            try expect(func().state == State.one);
+        }
+        const Outer = union(enum) {
+            state: State,
+        };
+        const State = union(enum) {
+            one: void,
+            two: u32,
+        };
+        fn func() Outer {
+            return Outer{ .state = State{ .one = {} } };
+        }
+    };
+    try S.entry();
+    comptime try S.entry();
+}
+
+test "@unionInit can modify a union type" {
+    const UnionInitEnum = union(enum) {
+        Boolean: bool,
+        Byte: u8,
+    };
+
+    var value: UnionInitEnum = undefined;
+
+    value = @unionInit(UnionInitEnum, "Boolean", true);
+    try expect(value.Boolean == true);
+    value.Boolean = false;
+    try expect(value.Boolean == false);
+
+    value = @unionInit(UnionInitEnum, "Byte", 2);
+    try expect(value.Byte == 2);
+    value.Byte = 3;
+    try expect(value.Byte == 3);
+}
+
+test "@unionInit can modify a pointer value" {
+    const UnionInitEnum = union(enum) {
+        Boolean: bool,
+        Byte: u8,
+    };
+
+    var value: UnionInitEnum = undefined;
+    var value_ptr = &value;
+
+    value_ptr.* = @unionInit(UnionInitEnum, "Boolean", true);
+    try expect(value.Boolean == true);
+
+    value_ptr.* = @unionInit(UnionInitEnum, "Byte", 2);
+    try expect(value.Byte == 2);
+}
+
+test "union no tag with struct member" {
+    const Struct = struct {};
+    const Union = union {
+        s: Struct,
+        pub fn foo(self: *@This()) void {
+            _ = self;
+        }
+    };
+    var u = Union{ .s = Struct{} };
+    u.foo();
+}
+
+fn testComparison() !void {
+    var x = Payload{ .A = 42 };
+    try expect(x == .A);
+    try expect(x != .B);
+    try expect(x != .C);
+    try expect((x == .B) == false);
+    try expect((x == .C) == false);
+    try expect((x != .A) == false);
+}
+
+test "comparison between union and enum literal" {
+    try testComparison();
+    comptime try testComparison();
+}
+
+test "packed union generates correctly aligned LLVM type" {
+    const U = packed union {
+        f1: fn () error{TestUnexpectedResult}!void,
+        f2: u32,
+    };
+    var foo = [_]U{
+        U{ .f1 = doTest },
+        U{ .f2 = 0 },
+    };
+    try foo[0].f1();
+}
+
+test "union with one member defaults to u0 tag type" {
+    const U0 = union(enum) {
+        X: u32,
+    };
+    comptime try expect(Tag(Tag(U0)) == u0);
+}
+
+test "union with comptime_int tag" {
+    const Union = union(enum(comptime_int)) {
+        X: u32,
+        Y: u16,
+        Z: u8,
+    };
+    comptime try expect(Tag(Tag(Union)) == comptime_int);
+}
+
+test "extern union doesn't trigger field check at comptime" {
+    const U = extern union {
+        x: u32,
+        y: u8,
+    };
+
+    const x = U{ .x = 0x55AAAA55 };
+    comptime try expect(x.y == 0x55);
+}
+
+const Foo1 = union(enum) {
+    f: struct {
+        x: usize,
+    },
+};
+var glbl: Foo1 = undefined;
+
+test "global union with single field is correctly initialized" {
+    glbl = Foo1{
+        .f = @typeInfo(Foo1).Union.fields[0].field_type{ .x = 123 },
+    };
+    try expect(glbl.f.x == 123);
+}
+
+pub const FooUnion = union(enum) {
+    U0: usize,
+    U1: u8,
+};
+
+var glbl_array: [2]FooUnion = undefined;
+
+test "initialize global array of union" {
+    glbl_array[1] = FooUnion{ .U1 = 2 };
+    glbl_array[0] = FooUnion{ .U0 = 1 };
+    try expect(glbl_array[0].U0 == 1);
+    try expect(glbl_array[1].U1 == 2);
+}
+
+test "anonymous union literal syntax" {
+    const S = struct {
+        const Number = union {
+            int: i32,
+            float: f64,
+        };
+
+        fn doTheTest() !void {
+            var i: Number = .{ .int = 42 };
+            var f = makeNumber();
+            try expect(i.int == 42);
+            try expect(f.float == 12.34);
+        }
+
+        fn makeNumber() Number {
+            return .{ .float = 12.34 };
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "update the tag value for zero-sized unions" {
+    const S = union(enum) {
+        U0: void,
+        U1: void,
+    };
+    var x = S{ .U0 = {} };
+    try expect(x == .U0);
+    x = S{ .U1 = {} };
+    try expect(x == .U1);
+}
+
+test "function call result coerces from tagged union to the tag" {
+    const S = struct {
+        const Arch = union(enum) {
+            One,
+            Two: usize,
+        };
+
+        const ArchTag = Tag(Arch);
+
+        fn doTheTest() !void {
+            var x: ArchTag = getArch1();
+            try expect(x == .One);
+
+            var y: ArchTag = getArch2();
+            try expect(y == .Two);
+        }
+
+        pub fn getArch1() Arch {
+            return .One;
+        }
+
+        pub fn getArch2() Arch {
+            return .{ .Two = 99 };
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "0-sized extern union definition" {
+    const U = extern union {
+        a: void,
+        const f = 1;
+    };
+
+    try expect(U.f == 1);
+}
+
+test "union initializer generates padding only if needed" {
+    const U = union(enum) {
+        A: u24,
+    };
+
+    var v = U{ .A = 532 };
+    try expect(v.A == 532);
+}
+
+test "runtime tag name with single field" {
+    const U = union(enum) {
+        A: i32,
+    };
+
+    var v = U{ .A = 42 };
+    try expect(std.mem.eql(u8, @tagName(v), "A"));
+}
+
+test "cast from anonymous struct to union" {
+    const S = struct {
+        const U = union(enum) {
+            A: u32,
+            B: []const u8,
+            C: void,
+        };
+        fn doTheTest() !void {
+            var y: u32 = 42;
+            const t0 = .{ .A = 123 };
+            const t1 = .{ .B = "foo" };
+            const t2 = .{ .C = {} };
+            const t3 = .{ .A = y };
+            const x0: U = t0;
+            var x1: U = t1;
+            const x2: U = t2;
+            var x3: U = t3;
+            try expect(x0.A == 123);
+            try expect(std.mem.eql(u8, x1.B, "foo"));
+            try expect(x2 == .C);
+            try expect(x3.A == y);
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "cast from pointer to anonymous struct to pointer to union" {
+    const S = struct {
+        const U = union(enum) {
+            A: u32,
+            B: []const u8,
+            C: void,
+        };
+        fn doTheTest() !void {
+            var y: u32 = 42;
+            const t0 = &.{ .A = 123 };
+            const t1 = &.{ .B = "foo" };
+            const t2 = &.{ .C = {} };
+            const t3 = &.{ .A = y };
+            const x0: *const U = t0;
+            var x1: *const U = t1;
+            const x2: *const U = t2;
+            var x3: *const U = t3;
+            try expect(x0.A == 123);
+            try expect(std.mem.eql(u8, x1.B, "foo"));
+            try expect(x2.* == .C);
+            try expect(x3.A == y);
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "method call on an empty union" {
+    const S = struct {
+        const MyUnion = union(MyUnionTag) {
+            pub const MyUnionTag = enum { X1, X2 };
+            X1: [0]u8,
+            X2: [0]u8,
+
+            pub fn useIt(self: *@This()) bool {
+                _ = self;
+                return true;
+            }
+        };
+
+        fn doTheTest() !void {
+            var u = MyUnion{ .X1 = [0]u8{} };
+            try expect(u.useIt());
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "switching on non exhaustive union" {
+    const S = struct {
+        const E = enum(u8) {
+            a,
+            b,
+            _,
+        };
+        const U = union(E) {
+            a: i32,
+            b: u32,
+        };
+        fn doTheTest() !void {
+            var a = U{ .a = 2 };
+            switch (a) {
+                .a => |val| try expect(val == 2),
+                .b => unreachable,
+            }
+        }
+    };
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "containers with single-field enums" {
+    const S = struct {
+        const A = union(enum) { f1 };
+        const B = union(enum) { f1: void };
+        const C = struct { a: A };
+        const D = struct { a: B };
+
+        fn doTheTest() !void {
+            var array1 = [1]A{A{ .f1 = {} }};
+            var array2 = [1]B{B{ .f1 = {} }};
+            try expect(array1[0] == .f1);
+            try expect(array2[0] == .f1);
+
+            var struct1 = C{ .a = A{ .f1 = {} } };
+            var struct2 = D{ .a = B{ .f1 = {} } };
+            try expect(struct1.a == .f1);
+            try expect(struct2.a == .f1);
+        }
+    };
+
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "@unionInit on union w/ tag but no fields" {
+    const S = struct {
+        const Type = enum(u8) { no_op = 105 };
+
+        const Data = union(Type) {
+            no_op: void,
+
+            pub fn decode(buf: []const u8) Data {
+                _ = buf;
+                return @unionInit(Data, "no_op", {});
+            }
+        };
+
+        comptime {
+            std.debug.assert(@sizeOf(Data) != 0);
+        }
+
+        fn doTheTest() !void {
+            var data: Data = .{ .no_op = .{} };
+            _ = data;
+            var o = Data.decode(&[_]u8{});
+            try expectEqual(Type.no_op, o);
+        }
+    };
+
+    try S.doTheTest();
+    comptime try S.doTheTest();
+}
+
+test "union enum type gets a separate scope" {
+    const S = struct {
+        const U = union(enum) {
+            a: u8,
+            const foo = 1;
+        };
+
+        fn doTheTest() !void {
+            try expect(!@hasDecl(Tag(U), "foo"));
+        }
+    };
+
+    try S.doTheTest();
+}
+test "anytype union field: issue #9233" {
+    const Baz = union(enum) { bar: anytype };
+    _ = Baz;
+}
diff --git a/test/behavior/widening.zig b/test/behavior/widening.zig
index efcbab9883..9c1694b368 100644
--- a/test/behavior/widening.zig
+++ b/test/behavior/widening.zig
@@ -17,3 +17,46 @@ test "implicit unsigned integer to signed integer" {
     var b: i16 = a;
     try expect(b == 250);
 }
+
+test "float widening" {
+    if (@import("builtin").zig_is_stage2) {
+        // This test is passing but it depends on compiler-rt symbols, which
+        // cannot yet be built with stage2 due to
+        // "TODO implement equality comparison between a union's tag value and an enum literal"
+        return error.SkipZigTest;
+    }
+    var a: f16 = 12.34;
+    var b: f32 = a;
+    var c: f64 = b;
+    var d: f128 = c;
+    try expect(a == b);
+    try expect(b == c);
+    try expect(c == d);
+}
+
+test "float widening f16 to f128" {
+    if (@import("builtin").zig_is_stage2) {
+        // This test is passing but it depends on compiler-rt symbols, which
+        // cannot yet be built with stage2 due to
+        // "TODO implement equality comparison between a union's tag value and an enum literal"
+        return error.SkipZigTest;
+    }
+    // TODO https://github.com/ziglang/zig/issues/3282
+    if (@import("builtin").stage2_arch == .aarch64) return error.SkipZigTest;
+    if (@import("builtin").stage2_arch == .powerpc64le) return error.SkipZigTest;
+
+    var x: f16 = 12.34;
+    var y: f128 = x;
+    try expect(x == y);
+}
+
+test "cast small unsigned to larger signed" {
+    try expect(castSmallUnsignedToLargerSigned1(200) == @as(i16, 200));
+    try expect(castSmallUnsignedToLargerSigned2(9999) == @as(i64, 9999));
+}
+fn castSmallUnsignedToLargerSigned1(x: u8) i16 {
+    return x;
+}
+fn castSmallUnsignedToLargerSigned2(x: u16) i64 {
+    return x;
+}
diff --git a/test/behavior/widening_stage1.zig b/test/behavior/widening_stage1.zig
deleted file mode 100644
index 0cec3988cb..0000000000
--- a/test/behavior/widening_stage1.zig
+++ /dev/null
@@ -1,34 +0,0 @@
-const std = @import("std");
-const expect = std.testing.expect;
-const mem = std.mem;
-
-test "float widening" {
-    var a: f16 = 12.34;
-    var b: f32 = a;
-    var c: f64 = b;
-    var d: f128 = c;
-    try expect(a == b);
-    try expect(b == c);
-    try expect(c == d);
-}
-
-test "float widening f16 to f128" {
-    // TODO https://github.com/ziglang/zig/issues/3282
-    if (@import("builtin").stage2_arch == .aarch64) return error.SkipZigTest;
-    if (@import("builtin").stage2_arch == .powerpc64le) return error.SkipZigTest;
-
-    var x: f16 = 12.34;
-    var y: f128 = x;
-    try expect(x == y);
-}
-
-test "cast small unsigned to larger signed" {
-    try expect(castSmallUnsignedToLargerSigned1(200) == @as(i16, 200));
-    try expect(castSmallUnsignedToLargerSigned2(9999) == @as(i64, 9999));
-}
-fn castSmallUnsignedToLargerSigned1(x: u8) i16 {
-    return x;
-}
-fn castSmallUnsignedToLargerSigned2(x: u16) i64 {
-    return x;
-}