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Diffstat (limited to '')
-rw-r--r-- | src/test/ui/issues/issue-57843.rs | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/src/test/ui/issues/issue-57843.rs b/src/test/ui/issues/issue-57843.rs new file mode 100644 index 000000000..11629690e --- /dev/null +++ b/src/test/ui/issues/issue-57843.rs @@ -0,0 +1,26 @@ +// Regression test for an ICE that occurred with the universes code: +// +// The signature of the closure `|_|` was being inferred to +// `exists<'r> fn(&'r u8)`. This should result in a type error since +// the signature `for<'r> fn(&'r u8)` is required. However, due to a +// bug in the type variable generalization code, the placeholder for +// `'r` was leaking out into the writeback phase, causing an ICE. + +trait ClonableFn<T> { + fn clone(&self) -> Box<dyn Fn(T)>; +} + +impl<T, F: 'static> ClonableFn<T> for F +where + F: Fn(T) + Clone, +{ + fn clone(&self) -> Box<dyn Fn(T)> { + Box::new(self.clone()) + } +} + +struct Foo(Box<dyn for<'a> ClonableFn<&'a bool>>); + +fn main() { + Foo(Box::new(|_| ())); //~ ERROR implementation of `FnOnce` is not general enough +} |