Auto merge of rust-lang#135524 - lcnr:fix-hang, r=<try>

don't check for overlap if its allowed regardless fixes rust-lang#135457. I am not a big fan of this tbh, want to figure out why the proof tree visitor is so damn slow here. r? `@compiler-errors`
rust-lang-ci · Jan 15, 2025 · 8d4ccf9 · 8d4ccf9
2 parents 93ba568 + aa75cc2
commit 8d4ccf9
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Showing 4 changed files with 67 additions and 51 deletions.
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -116,28 +116,39 @@ pub fn overlapping_impls(
         return None;
     }
 
-    let _overlap_with_bad_diagnostics = overlap(
-        tcx,
-        TrackAmbiguityCauses::No,
-        skip_leak_check,
-        impl1_def_id,
-        impl2_def_id,
-        overlap_mode,
-    )?;
-
-    // In the case where we detect an error, run the check again, but
-    // this time tracking intercrate ambiguity causes for better
-    // diagnostics. (These take time and can lead to false errors.)
-    let overlap = overlap(
-        tcx,
-        TrackAmbiguityCauses::Yes,
-        skip_leak_check,
-        impl1_def_id,
-        impl2_def_id,
-        overlap_mode,
-    )
-    .unwrap();
-    Some(overlap)
+    if tcx.next_trait_solver_in_coherence() {
+        overlap(
+            tcx,
+            TrackAmbiguityCauses::Yes,
+            skip_leak_check,
+            impl1_def_id,
+            impl2_def_id,
+            overlap_mode,
+        )
+    } else {
+        let _overlap_with_bad_diagnostics = overlap(
+            tcx,
+            TrackAmbiguityCauses::No,
+            skip_leak_check,
+            impl1_def_id,
+            impl2_def_id,
+            overlap_mode,
+        )?;
+
+        // In the case where we detect an error, run the check again, but
+        // this time tracking intercrate ambiguity causes for better
+        // diagnostics. (These take time and can lead to false errors.)
+        let overlap = overlap(
+            tcx,
+            TrackAmbiguityCauses::Yes,
+            skip_leak_check,
+            impl1_def_id,
+            impl2_def_id,
+            overlap_mode,
+        )
+        .unwrap();
+        Some(overlap)
+    }
 }
 
 fn fresh_impl_header<'tcx>(infcx: &InferCtxt<'tcx>, impl_def_id: DefId) -> ty::ImplHeader<'tcx> {

diff --git a/compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs b/compiler/rustc_trait_selection/src/traits/specialize/specialization_graph.rs
@@ -138,35 +138,44 @@ impl<'tcx> Children {
             };
 
             let last_lint_mut = &mut last_lint;
-            let (le, ge) = traits::overlapping_impls(
-                tcx,
-                possible_sibling,
-                impl_def_id,
-                traits::SkipLeakCheck::Yes,
-                overlap_mode,
-            )
-            .map_or(Ok((false, false)), |overlap| {
-                if let Some(overlap_kind) =
-                    tcx.impls_are_allowed_to_overlap(impl_def_id, possible_sibling)
-                {
-                    match overlap_kind {
-                        ty::ImplOverlapKind::Permitted { marker: _ } => {}
-                        ty::ImplOverlapKind::FutureCompatOrderDepTraitObjects => {
-                            *last_lint_mut = Some(FutureCompatOverlapError {
-                                error: create_overlap_error(overlap),
-                                kind: FutureCompatOverlapErrorKind::OrderDepTraitObjects,
-                            });
+
+            let overlap_kind = tcx.impls_are_allowed_to_overlap(impl_def_id, possible_sibling);
+            let (le, ge) = if let Some(ty::ImplOverlapKind::Permitted { marker: _ }) = overlap_kind
+            {
+                (false, false)
+            } else {
+                traits::overlapping_impls(
+                    tcx,
+                    possible_sibling,
+                    impl_def_id,
+                    traits::SkipLeakCheck::Yes,
+                    overlap_mode,
+                )
+                .map_or(Ok((false, false)), |overlap| {
+                    if let Some(overlap_kind) = overlap_kind {
+                        match overlap_kind {
+                            ty::ImplOverlapKind::Permitted { marker: _ } => {}
+                            ty::ImplOverlapKind::FutureCompatOrderDepTraitObjects => {
+                                *last_lint_mut = Some(FutureCompatOverlapError {
+                                    error: create_overlap_error(overlap),
+                                    kind: FutureCompatOverlapErrorKind::OrderDepTraitObjects,
+                                });
+                            }
                         }
-                    }
 
-                    return Ok((false, false));
-                }
+                        return Ok((false, false));
+                    }
 
-                let le = tcx.specializes((impl_def_id, possible_sibling));
-                let ge = tcx.specializes((possible_sibling, impl_def_id));
+                    let le = tcx.specializes((impl_def_id, possible_sibling));
+                    let ge = tcx.specializes((possible_sibling, impl_def_id));
 
-                if le == ge { report_overlap_error(overlap, last_lint_mut) } else { Ok((le, ge)) }
-            })?;
+                    if le == ge {
+                        report_overlap_error(overlap, last_lint_mut)
+                    } else {
+                        Ok((le, ge))
+                    }
+                })?
+            };
 
             if le && !ge {
                 debug!(

diff --git a/tests/ui/coherence/occurs-check/associated-type.next.stderr b/tests/ui/coherence/occurs-check/associated-type.next.stderr
@@ -1,7 +1,5 @@
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
 error[E0119]: conflicting implementations of trait `Overlap<for<'a> fn(&'a (), ())>` for type `for<'a> fn(&'a (), ())`
   --> $DIR/associated-type.rs:32:1
    |

diff --git a/tests/ui/coherence/occurs-check/associated-type.old.stderr b/tests/ui/coherence/occurs-check/associated-type.old.stderr
@@ -1,7 +1,5 @@
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
  WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
- WARN rustc_infer::infer::relate::generalize may incompletely handle alias type: AliasTy { args: [*const ?1t, '^0.Named(DefId(0:27 ~ associated_type[f554]::{impl#3}::'a#1), "'a")], def_id: DefId(0:5 ~ associated_type[f554]::ToUnit::Unit), .. }
 error[E0119]: conflicting implementations of trait `Overlap<for<'a> fn(&'a (), ())>` for type `for<'a> fn(&'a (), ())`
   --> $DIR/associated-type.rs:32:1
    |