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Dont ICE on copy error being suppressed due to overflow

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+36

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+36

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Lines changed: 5 additions & 4 deletions

Original file line number	Diff line number	Diff line change
`@@ -303,10 +303,11 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {`
`303`	`303`	`}`
`304`	`304`
`305`	`305`	`fn has_ambiguous_copy(&mut self, ty: Ty<'tcx>) -> bool {`
`306`		`- let Some(copy_trait_def) = self.infcx.tcx.lang_items().copy_trait() else { return false };`
`307`		`- // This is only going to be ambiguous if there are incoherent impls, because otherwise`
`308`		`- // ambiguity should never happen in MIR.`
`309`		`- self.infcx.type_implements_trait(copy_trait_def, [ty], self.infcx.param_env).may_apply()`
	`306`	`+ let Some(copy_def_id) = self.infcx.tcx.lang_items().copy_trait() else { return false };`
	`307`	`+`
	`308`	+ // Avoid bogus move errors because of an incoherent `Copy` impl.
	`309`	`+ self.infcx.type_implements_trait(copy_def_id, [ty], self.infcx.param_env).may_apply()`
	`310`	`+ && self.infcx.tcx.coherent_trait(copy_def_id).is_err()`
`310`	`311`	`}`
`311`	`312`
`312`	`313`	`fn report_cannot_move_from_static(&mut self, place: Place<'tcx>, span: Span) -> Diag<'infcx> {`

Lines changed: 16 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,16 @@`
	`1`	`+// Regression test for <https://github.com/rust-lang/rust/issues/144165>.`
	`2`	`+`
	`3`	+// We were previously suppressing the copy error in the `Clone` impl because we assumed
	`4`	+// that the only way we get `Copy` ambiguity errors was due to incoherent impls. This is
	`5`	`+// not true, since ambiguities can be encountered due to overflows (among other ways).`
	`6`	`+`
	`7`	`+struct S<T: 'static>(Option<&'static T>);`
	`8`	`+`
	`9`	`+impl<T: 'static> Copy for S<T> where S<T>: Copy + Clone {}`
	`10`	`+impl<T: 'static> Clone for S<T> {`
	`11`	`+ fn clone(&self) -> Self {`
	`12`	`+ *self`
	`13`	+ //~^ ERROR cannot move out of `*self` which is behind a shared reference
	`14`	`+ }`
	`15`	`+}`
	`16`	`+fn main() {}`

Lines changed: 15 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,15 @@`
	`1`	+error[E0507]: cannot move out of `*self` which is behind a shared reference
	`2`	`+ --> $DIR/copy-overflow.rs:12:9`
	`3`	`+ \|`
	`4`	`+LL \| *self`
	`5`	+ \| ^^^^^ move occurs because `*self` has type `S<T>`, which does not implement the `Copy` trait
	`6`	`+ \|`
	`7`	`+help: consider cloning the value if the performance cost is acceptable`
	`8`	`+ \|`
	`9`	`+LL - *self`
	`10`	`+LL + self.clone()`
	`11`	`+ \|`
	`12`	`+`
	`13`	`+error: aborting due to 1 previous error`
	`14`	`+`
	`15`	+For more information about this error, try `rustc --explain E0507`.

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