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e1599b0c XL |
1 | // run-pass |
2 | ||
3 | //! Make sure that we read and write enum discriminants correctly for corner cases caused | |
4 | //! by layout optimizations. | |
5 | ||
6 | const OVERFLOW: usize = { | |
7 | // Tests for https://github.com/rust-lang/rust/issues/62138. | |
8 | #[repr(u8)] | |
9 | #[allow(dead_code)] | |
10 | enum WithWraparoundInvalidValues { | |
11 | X = 1, | |
12 | Y = 254, | |
13 | } | |
14 | ||
15 | #[allow(dead_code)] | |
16 | enum Foo { | |
17 | A, | |
18 | B, | |
19 | C(WithWraparoundInvalidValues), | |
20 | } | |
21 | ||
22 | let x = Foo::B; | |
23 | match x { | |
24 | Foo::B => 0, | |
25 | _ => panic!(), | |
26 | } | |
27 | }; | |
28 | ||
29 | const MORE_OVERFLOW: usize = { | |
30 | pub enum Infallible {} | |
31 | ||
32 | // The check that the `bool` field of `V1` is encoding a "niche variant" | |
33 | // (i.e. not `V1`, so `V3` or `V4`) used to be mathematically incorrect, | |
34 | // causing valid `V1` values to be interpreted as other variants. | |
35 | #[allow(dead_code)] | |
36 | pub enum E1 { | |
37 | V1 { f: bool }, | |
38 | V2 { f: Infallible }, | |
39 | V3, | |
40 | V4, | |
41 | } | |
42 | ||
43 | // Computing the discriminant used to be done using the niche type (here `u8`, | |
44 | // from the `bool` field of `V1`), overflowing for variants with large enough | |
45 | // indices (`V3` and `V4`), causing them to be interpreted as other variants. | |
46 | #[allow(dead_code)] | |
47 | pub enum E2<X> { | |
48 | V1 { f: bool }, | |
49 | ||
50 | /*_00*/ _01(X), _02(X), _03(X), _04(X), _05(X), _06(X), _07(X), | |
51 | _08(X), _09(X), _0A(X), _0B(X), _0C(X), _0D(X), _0E(X), _0F(X), | |
52 | _10(X), _11(X), _12(X), _13(X), _14(X), _15(X), _16(X), _17(X), | |
53 | _18(X), _19(X), _1A(X), _1B(X), _1C(X), _1D(X), _1E(X), _1F(X), | |
54 | _20(X), _21(X), _22(X), _23(X), _24(X), _25(X), _26(X), _27(X), | |
55 | _28(X), _29(X), _2A(X), _2B(X), _2C(X), _2D(X), _2E(X), _2F(X), | |
56 | _30(X), _31(X), _32(X), _33(X), _34(X), _35(X), _36(X), _37(X), | |
57 | _38(X), _39(X), _3A(X), _3B(X), _3C(X), _3D(X), _3E(X), _3F(X), | |
58 | _40(X), _41(X), _42(X), _43(X), _44(X), _45(X), _46(X), _47(X), | |
59 | _48(X), _49(X), _4A(X), _4B(X), _4C(X), _4D(X), _4E(X), _4F(X), | |
60 | _50(X), _51(X), _52(X), _53(X), _54(X), _55(X), _56(X), _57(X), | |
61 | _58(X), _59(X), _5A(X), _5B(X), _5C(X), _5D(X), _5E(X), _5F(X), | |
62 | _60(X), _61(X), _62(X), _63(X), _64(X), _65(X), _66(X), _67(X), | |
63 | _68(X), _69(X), _6A(X), _6B(X), _6C(X), _6D(X), _6E(X), _6F(X), | |
64 | _70(X), _71(X), _72(X), _73(X), _74(X), _75(X), _76(X), _77(X), | |
65 | _78(X), _79(X), _7A(X), _7B(X), _7C(X), _7D(X), _7E(X), _7F(X), | |
66 | _80(X), _81(X), _82(X), _83(X), _84(X), _85(X), _86(X), _87(X), | |
67 | _88(X), _89(X), _8A(X), _8B(X), _8C(X), _8D(X), _8E(X), _8F(X), | |
68 | _90(X), _91(X), _92(X), _93(X), _94(X), _95(X), _96(X), _97(X), | |
69 | _98(X), _99(X), _9A(X), _9B(X), _9C(X), _9D(X), _9E(X), _9F(X), | |
70 | _A0(X), _A1(X), _A2(X), _A3(X), _A4(X), _A5(X), _A6(X), _A7(X), | |
71 | _A8(X), _A9(X), _AA(X), _AB(X), _AC(X), _AD(X), _AE(X), _AF(X), | |
72 | _B0(X), _B1(X), _B2(X), _B3(X), _B4(X), _B5(X), _B6(X), _B7(X), | |
73 | _B8(X), _B9(X), _BA(X), _BB(X), _BC(X), _BD(X), _BE(X), _BF(X), | |
74 | _C0(X), _C1(X), _C2(X), _C3(X), _C4(X), _C5(X), _C6(X), _C7(X), | |
75 | _C8(X), _C9(X), _CA(X), _CB(X), _CC(X), _CD(X), _CE(X), _CF(X), | |
76 | _D0(X), _D1(X), _D2(X), _D3(X), _D4(X), _D5(X), _D6(X), _D7(X), | |
77 | _D8(X), _D9(X), _DA(X), _DB(X), _DC(X), _DD(X), _DE(X), _DF(X), | |
78 | _E0(X), _E1(X), _E2(X), _E3(X), _E4(X), _E5(X), _E6(X), _E7(X), | |
79 | _E8(X), _E9(X), _EA(X), _EB(X), _EC(X), _ED(X), _EE(X), _EF(X), | |
80 | _F0(X), _F1(X), _F2(X), _F3(X), _F4(X), _F5(X), _F6(X), _F7(X), | |
81 | _F8(X), _F9(X), _FA(X), _FB(X), _FC(X), _FD(X), _FE(X), _FF(X), | |
82 | ||
83 | V3, | |
84 | V4, | |
85 | } | |
86 | ||
87 | if let E1::V2 { .. } = (E1::V1 { f: true }) { | |
88 | unreachable!() | |
89 | } | |
90 | if let E1::V1 { .. } = (E1::V1 { f: true }) { | |
91 | } else { | |
92 | unreachable!() | |
93 | } | |
94 | ||
95 | if let E2::V1 { .. } = E2::V3::<Infallible> { | |
96 | unreachable!() | |
97 | } | |
98 | if let E2::V3 { .. } = E2::V3::<Infallible> { | |
99 | } else { | |
100 | unreachable!() | |
101 | } | |
102 | ||
103 | 0 | |
104 | }; | |
105 | ||
106 | fn main() { | |
107 | assert_eq!(OVERFLOW, 0); | |
108 | assert_eq!(MORE_OVERFLOW, 0); | |
109 | } |