diff options
| -rw-r--r-- | compiler/rustc_const_eval/src/interpret/projection.rs | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/compiler/rustc_const_eval/src/interpret/projection.rs b/compiler/rustc_const_eval/src/interpret/projection.rs index 0f3b6b25c61..9a034ba22b9 100644 --- a/compiler/rustc_const_eval/src/interpret/projection.rs +++ b/compiler/rustc_const_eval/src/interpret/projection.rs @@ -208,6 +208,24 @@ where if layout.abi.is_uninhabited() { // `read_discriminant` should have excluded uninhabited variants... but ConstProp calls // us on dead code. + // In the future we might want to allow this to permit code like this: + // (this is a Rust/MIR pseudocode mix) + // ``` + // enum Option2 { + // Some(i32, !), + // None, + // } + // + // fn panic() -> ! { panic!() } + // + // let x: Option2; + // x.Some.0 = 42; + // x.Some.1 = panic(); + // SetDiscriminant(x, Some); + // ``` + // However, for now we don't generate such MIR, and this check here *has* found real + // bugs (see https://github.com/rust-lang/rust/issues/115145), so we will keep rejecting + // it. throw_inval!(ConstPropNonsense) } // This cannot be `transmute` as variants *can* have a smaller size than the entire enum. |