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| author | Dylan DPC <99973273+Dylan-DPC@users.noreply.github.com> | 2023-02-24 12:02:42 +0530 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2023-02-24 12:02:42 +0530 |
| commit | 251293ef5e563b11fc7d46b6e1a31ef740f26455 (patch) | |
| tree | d6e5944a73ecf5a78c5d3d9f0d64564af46a70dc /tests/ui/typeck | |
| parent | 440113ddf68522a3cecac66dc3cd0bdf88718013 (diff) | |
| parent | eb1f9babecbe51b7580e71ed8e558ff40eeee96c (diff) | |
| download | rust-251293ef5e563b11fc7d46b6e1a31ef740f26455.tar.gz | |
Rollup merge of #108287 - compiler-errors:new-solver-bad-cast, r=spastorino
Add test for bad cast with deferred projection equality
1. Unification during coercion (`Coerce::unify`) needs to consider deferred projection obligations (at least pass over them with `predicate_may_hold` or something, to disqualify any totally wrong unifications) -- otherwise, we'll shallowly consider `<u8 as Add>::Output` and `char` as coercible during `FnCtxt::try_coerce`, which will fail later when the nested obligations are registered and processed.
2. Cast checking needs to be able to structurally normalize types so it sees `u8` instead of `<u8 as Add>::Output`. Otherwise it'll always consider the latter as part of a non-primitive cast. Currently `FnCtxt::normalize` doesn't do anything useful here, interestingly.
I tried looking into both of these and it's not immediately clear where to refactor existing typeck code to fix this (at least the latter), but I'm gonna commit a test for it at least so we don't forget. This is one of the issues that's keeping us from building larger projects.
Diffstat (limited to 'tests/ui/typeck')
| -rw-r--r-- | tests/ui/typeck/lazy-norm/cast-checks-handling-projections.rs | 6 | ||||
| -rw-r--r-- | tests/ui/typeck/lazy-norm/cast-checks-handling-projections.stderr | 9 |
2 files changed, 15 insertions, 0 deletions
diff --git a/tests/ui/typeck/lazy-norm/cast-checks-handling-projections.rs b/tests/ui/typeck/lazy-norm/cast-checks-handling-projections.rs new file mode 100644 index 00000000000..5ff567cd07c --- /dev/null +++ b/tests/ui/typeck/lazy-norm/cast-checks-handling-projections.rs @@ -0,0 +1,6 @@ +// compile-flags: -Ztrait-solver=next +// known-bug: unknown + +fn main() { + (0u8 + 0u8) as char; +} diff --git a/tests/ui/typeck/lazy-norm/cast-checks-handling-projections.stderr b/tests/ui/typeck/lazy-norm/cast-checks-handling-projections.stderr new file mode 100644 index 00000000000..6b09ccd5214 --- /dev/null +++ b/tests/ui/typeck/lazy-norm/cast-checks-handling-projections.stderr @@ -0,0 +1,9 @@ +error[E0271]: type mismatch resolving `char == <u8 as Add>::Output` + --> $DIR/cast-checks-handling-projections.rs:5:5 + | +LL | (0u8 + 0u8) as char; + | ^^^^^^^^^^^ types differ + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0271`. |