diff options
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/coherence.rs | 49 |
1 files changed, 33 insertions, 16 deletions
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs index 42b7139c006..f6101d78f41 100644 --- a/compiler/rustc_trait_selection/src/traits/coherence.rs +++ b/compiler/rustc_trait_selection/src/traits/coherence.rs @@ -201,17 +201,17 @@ fn overlap_within_probe<'cx, 'tcx>( match overlap_mode(tcx, impl1_def_id, impl2_def_id) { OverlapMode::Stable => { - if stable_disjoint(selcx, param_env, &impl1_header, impl2_header, OverlapMode::Stable) { + if stable_disjoint(selcx, param_env, &impl1_header, impl2_header) { return None; } } OverlapMode::Strict => { - if stable_disjoint(selcx, param_env, &impl1_header, impl2_header, OverlapMode::Strict) { + if strict_disjoint(selcx, param_env, &impl1_header, impl2_header) { return None; } } OverlapMode::WithNegative => { - if stable_disjoint(selcx, param_env, &impl1_header, impl2_header, OverlapMode::Stable) + if stable_disjoint(selcx, param_env, &impl1_header, impl2_header) || explicit_disjoint(selcx, impl1_def_id, impl2_def_id) || explicit_disjoint(selcx, impl2_def_id, impl1_def_id) { @@ -244,7 +244,35 @@ fn stable_disjoint<'cx, 'tcx>( param_env: ty::ParamEnv<'tcx>, impl1_header: &ty::ImplHeader<'tcx>, impl2_header: ty::ImplHeader<'tcx>, - overlap_mode: OverlapMode, +) -> bool { + let infcx = selcx.infcx(); + let tcx = infcx.tcx; + + disjoint_with_filter(selcx, param_env, impl1_header, impl2_header, |selcx, o| { + loose_check(selcx, o) || tcx.features().negative_impls && strict_check(selcx, o) + }) +} + +fn strict_disjoint<'cx, 'tcx>( + selcx: &mut SelectionContext<'cx, 'tcx>, + param_env: ty::ParamEnv<'tcx>, + impl1_header: &ty::ImplHeader<'tcx>, + impl2_header: ty::ImplHeader<'tcx>, +) -> bool { + disjoint_with_filter(selcx, param_env, impl1_header, impl2_header, |selcx, o| { + strict_check(selcx, o) + }) +} + +fn disjoint_with_filter<'cx, 'tcx>( + selcx: &mut SelectionContext<'cx, 'tcx>, + param_env: ty::ParamEnv<'tcx>, + impl1_header: &ty::ImplHeader<'tcx>, + impl2_header: ty::ImplHeader<'tcx>, + mut filter: impl FnMut( + &mut SelectionContext<'cx, 'tcx>, + &rustc_infer::traits::Obligation<'tcx, rustc_middle::ty::Predicate<'tcx>>, + ) -> bool, ) -> bool { debug!("overlap: impl1_header={:?}", impl1_header); debug!("overlap: impl2_header={:?}", impl2_header); @@ -285,7 +313,6 @@ fn stable_disjoint<'cx, 'tcx>( // hold we need to check if `&'?a str: !Error` holds, if doesn't hold there's overlap because // at some point an impl for `&'?a str: Error` could be added. let infcx = selcx.infcx(); - let tcx = infcx.tcx; let opt_failing_obligation = impl1_header .predicates .iter() @@ -299,17 +326,7 @@ fn stable_disjoint<'cx, 'tcx>( predicate: p, }) .chain(obligations) - .find(|o| { - // if both impl headers are set to strict coherence it means that this will be accepted - // only if it's stated that T: !Trait. So only prove that the negated obligation holds. - match overlap_mode { - OverlapMode::Stable => { - loose_check(selcx, o) || tcx.features().negative_impls && strict_check(selcx, o) - } - OverlapMode::Strict => strict_check(selcx, o), - OverlapMode::WithNegative => loose_check(selcx, o), - } - }); + .find(|o| filter(selcx, o)); // FIXME: the call to `selcx.predicate_may_hold_fatal` above should be ported // to the canonical trait query form, `infcx.predicate_may_hold`, once // the new system supports intercrate mode (which coherence needs). |