rust-lang · bors · Mar 7, 2024 · Feb 15, 2024 · oli-obk · Feb 15, 2024
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -248,6 +248,8 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) -> Result<()
             let header = tcx.impl_trait_header(def_id);
             let is_auto = header
                 .is_some_and(|header| tcx.trait_is_auto(header.skip_binder().trait_ref.def_id));
+
+            crate::impl_wf_check::check_impl_wf(tcx, def_id)?;
             let mut res = Ok(());
             if let (hir::Defaultness::Default { .. }, true) = (impl_.defaultness, is_auto) {
                 let sp = impl_.of_trait.as_ref().map_or(item.span, |t| t.path.span);

diff --git a/compiler/rustc_hir_analysis/src/impl_wf_check.rs b/compiler/rustc_hir_analysis/src/impl_wf_check.rs
@@ -14,8 +14,7 @@ use min_specialization::check_min_specialization;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{codes::*, struct_span_code_err};
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::{LocalDefId, LocalModDefId};
-use rustc_middle::query::Providers;
+use rustc_hir::def_id::LocalDefId;
 use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 use rustc_span::{ErrorGuaranteed, Span, Symbol};
 
@@ -51,23 +50,16 @@ mod min_specialization;
 /// impl<'a> Trait<Foo> for Bar { type X = &'a i32; }
 /// //   ^ 'a is unused and appears in assoc type, error
 /// ```
-fn check_mod_impl_wf(tcx: TyCtxt<'_>, module_def_id: LocalModDefId) -> Result<(), ErrorGuaranteed> {
+pub fn check_impl_wf(tcx: TyCtxt<'_>, impl_def_id: LocalDefId) -> Result<(), ErrorGuaranteed> {
     let min_specialization = tcx.features().min_specialization;
-    let module = tcx.hir_module_items(module_def_id);
     let mut res = Ok(());
-    for id in module.items() {
-        if matches!(tcx.def_kind(id.owner_id), DefKind::Impl { .. }) {
-            res = res.and(enforce_impl_params_are_constrained(tcx, id.owner_id.def_id));
-            if min_specialization {
-                res = res.and(check_min_specialization(tcx, id.owner_id.def_id));
-            }
-        }
+    debug_assert!(matches!(tcx.def_kind(impl_def_id), DefKind::Impl { .. }));
+    res = res.and(enforce_impl_params_are_constrained(tcx, impl_def_id));
+    if min_specialization {
+        res = res.and(check_min_specialization(tcx, impl_def_id));
     }
-    res
-}
 
-pub fn provide(providers: &mut Providers) {
-    *providers = Providers { check_mod_impl_wf, ..*providers };
+    res
 }
 
 fn enforce_impl_params_are_constrained(

diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
@@ -153,7 +153,6 @@ pub fn provide(providers: &mut Providers) {
     check_unused::provide(providers);
     variance::provide(providers);
     outlives::provide(providers);
-    impl_wf_check::provide(providers);
     hir_wf_check::provide(providers);
 }
 
@@ -171,29 +170,22 @@ pub fn check_crate(tcx: TyCtxt<'_>) -> Result<(), ErrorGuaranteed> {
     }
 
     tcx.sess.time("coherence_checking", || {
-        // Check impls constrain their parameters
-        let res =
-            tcx.hir().try_par_for_each_module(|module| tcx.ensure().check_mod_impl_wf(module));
+        tcx.hir().par_for_each_module(|module| {
+            let _ = tcx.ensure().check_mod_type_wf(module);
+        });
 
         for &trait_def_id in tcx.all_local_trait_impls(()).keys() {
             let _ = tcx.ensure().coherent_trait(trait_def_id);
         }
         // these queries are executed for side-effects (error reporting):
         let _ = tcx.ensure().crate_inherent_impls(());
         let _ = tcx.ensure().crate_inherent_impls_overlap_check(());
-        res
-    })?;
+    });
 
     if tcx.features().rustc_attrs {
         tcx.sess.time("variance_testing", || variance::test::test_variance(tcx))?;
     }
 
-    tcx.sess.time("wf_checking", || {
-        tcx.hir().par_for_each_module(|module| {
-            let _ = tcx.ensure().check_mod_type_wf(module);
-        })
-    });
-
     if tcx.features().rustc_attrs {
         collect::test_opaque_hidden_types(tcx)?;
     }

diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
@@ -955,11 +955,6 @@ rustc_queries! {
         desc { |tcx| "checking deathness of variables in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_impl_wf(key: LocalModDefId) -> Result<(), ErrorGuaranteed> {
-        desc { |tcx| "checking that impls are well-formed in {}", describe_as_module(key, tcx) }
-        ensure_forwards_result_if_red
-    }
-
     query check_mod_type_wf(key: LocalModDefId) -> Result<(), ErrorGuaranteed> {
         desc { |tcx| "checking that types are well-formed in {}", describe_as_module(key, tcx) }
         ensure_forwards_result_if_red

diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
@@ -2593,10 +2593,19 @@ impl<'a: 'ast, 'b, 'ast, 'tcx> LateResolutionVisitor<'a, 'b, 'ast, 'tcx> {
                     let span = *entry.get();
                     let err = ResolutionError::NameAlreadyUsedInParameterList(ident.name, span);
                     self.report_error(param.ident.span, err);
-                    if let GenericParamKind::Lifetime = param.kind {
-                        // Record lifetime res, so lowering knows there is something fishy.
-                        self.record_lifetime_param(param.id, LifetimeRes::Error);
-                    }
+                    let rib = match param.kind {
+                        GenericParamKind::Lifetime => {
+                            // Record lifetime res, so lowering knows there is something fishy.
+                            self.record_lifetime_param(param.id, LifetimeRes::Error);
+                            continue;
+                        }
+                        GenericParamKind::Type { .. } => &mut function_type_rib,
+                        GenericParamKind::Const { .. } => &mut function_value_rib,
+                    };
+
+                    // Taint the resolution in case of errors to prevent follow up errors in typeck
+                    self.r.record_partial_res(param.id, PartialRes::new(Res::Err));
+                    rib.bindings.insert(ident, Res::Err);
                     continue;
                 }
                 Entry::Vacant(entry) => {

diff --git a/compiler/rustc_traits/src/codegen.rs b/compiler/rustc_traits/src/codegen.rs
@@ -6,7 +6,7 @@
 use rustc_infer::infer::TyCtxtInferExt;
 use rustc_infer::traits::{FulfillmentErrorCode, TraitEngineExt as _};
 use rustc_middle::traits::CodegenObligationError;
-use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::ty::{self, TyCtxt, TypeVisitableExt};
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
 use rustc_trait_selection::traits::{
     ImplSource, Obligation, ObligationCause, SelectionContext, TraitEngine, TraitEngineExt,
@@ -72,6 +72,13 @@ pub fn codegen_select_candidate<'tcx>(
 
     let impl_source = infcx.resolve_vars_if_possible(impl_source);
     let impl_source = infcx.tcx.erase_regions(impl_source);
+    if impl_source.has_infer() {
+        // Unused lifetimes on an impl get replaced with inference vars, but never resolved,
+        // causing the return value of a query to contain inference vars. We do not have a concept
+        // for this and will in fact ICE in stable hashing of the return value. So bail out instead.
+        infcx.tcx.dcx().has_errors().unwrap();
+        return Err(CodegenObligationError::FulfillmentError);
+    }
 
     Ok(&*tcx.arena.alloc(impl_source))
 }
diff --git a/tests/rustdoc-ui/not-wf-ambiguous-normalization.rs b/tests/rustdoc-ui/not-wf-ambiguous-normalization.rs
@@ -12,7 +12,7 @@ struct DefaultAllocator;
 // `<DefaultAllocator as Allocator>::Buffer` to be ambiguous,
 // which caused an ICE with `-Znormalize-docs`.
 impl<T> Allocator for DefaultAllocator {
-    //~^ ERROR: type annotations needed
+    //~^ ERROR: the type parameter `T` is not constrained
     type Buffer = ();
 }
 

diff --git a/tests/rustdoc-ui/not-wf-ambiguous-normalization.stderr b/tests/rustdoc-ui/not-wf-ambiguous-normalization.stderr
@@ -1,9 +1,9 @@
-error[E0282]: type annotations needed
-  --> $DIR/not-wf-ambiguous-normalization.rs:14:23
+error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predicates
+  --> $DIR/not-wf-ambiguous-normalization.rs:14:6
    |
 LL | impl<T> Allocator for DefaultAllocator {
-   |                       ^^^^^^^^^^^^^^^^ cannot infer type for type parameter `T`
+   |      ^ unconstrained type parameter
 
 error: aborting due to 1 previous error
 
-For more information about this error, try `rustc --explain E0282`.
+For more information about this error, try `rustc --explain E0207`.
diff --git a/tests/ui/associated-types/issue-38821.stderr b/tests/ui/associated-types/issue-38821.stderr
@@ -1,22 +1,3 @@
-error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
-  --> $DIR/issue-38821.rs:23:17
-   |
-LL | #[derive(Debug, Copy, Clone)]
-   |                 ^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`, which is required by `<Col as Expression>::SqlType: IntoNullable`
-   |
-note: required for `<Col as Expression>::SqlType` to implement `IntoNullable`
-  --> $DIR/issue-38821.rs:9:18
-   |
-LL | impl<T: NotNull> IntoNullable for T {
-   |         -------  ^^^^^^^^^^^^     ^
-   |         |
-   |         unsatisfied trait bound introduced here
-   = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: consider further restricting the associated type
-   |
-LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Col as Expression>::SqlType: NotNull,
-   |                                                                       +++++++++++++++++++++++++++++++++++++++
-
 error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
   --> $DIR/issue-38821.rs:40:1
    |
@@ -129,6 +110,25 @@ LL | impl<T: NotNull> IntoNullable for T {
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
    = note: this error originates in the derive macro `Debug` (in Nightly builds, run with -Z macro-backtrace for more info)
 
+error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
+  --> $DIR/issue-38821.rs:23:17
+   |
+LL | #[derive(Debug, Copy, Clone)]
+   |                 ^^^^ the trait `NotNull` is not implemented for `<Col as Expression>::SqlType`, which is required by `<Col as Expression>::SqlType: IntoNullable`
+   |
+note: required for `<Col as Expression>::SqlType` to implement `IntoNullable`
+  --> $DIR/issue-38821.rs:9:18
+   |
+LL | impl<T: NotNull> IntoNullable for T {
+   |         -------  ^^^^^^^^^^^^     ^
+   |         |
+   |         unsatisfied trait bound introduced here
+   = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider further restricting the associated type
+   |
+LL |     Expr: Expression<SqlType=<Col::SqlType as IntoNullable>::Nullable>, <Col as Expression>::SqlType: NotNull,
+   |                                                                       +++++++++++++++++++++++++++++++++++++++
+
 error[E0277]: the trait bound `<Col as Expression>::SqlType: NotNull` is not satisfied
   --> $DIR/issue-38821.rs:23:17
    |

diff --git a/tests/ui/coherence/coherence-orphan.stderr b/tests/ui/coherence/coherence-orphan.stderr
@@ -10,17 +10,6 @@ LL | impl TheTrait<usize> for isize {}
    |
    = note: define and implement a trait or new type instead
 
-error[E0117]: only traits defined in the current crate can be implemented for types defined outside of the crate
-  --> $DIR/coherence-orphan.rs:20:1
-   |
-LL | impl !Send for Vec<isize> {}
-   | ^^^^^^^^^^^^^^^----------
-   | |              |
-   | |              `Vec` is not defined in the current crate
-   | impl doesn't use only types from inside the current crate
-   |
-   = note: define and implement a trait or new type instead
-
 error[E0046]: not all trait items implemented, missing: `the_fn`
   --> $DIR/coherence-orphan.rs:10:1
    |
@@ -45,6 +34,17 @@ LL | impl TheTrait<isize> for TheType {}
    |
    = help: implement the missing item: `fn the_fn(&self) { todo!() }`
 
+error[E0117]: only traits defined in the current crate can be implemented for types defined outside of the crate
+  --> $DIR/coherence-orphan.rs:20:1
+   |
+LL | impl !Send for Vec<isize> {}
+   | ^^^^^^^^^^^^^^^----------
+   | |              |
+   | |              `Vec` is not defined in the current crate
+   | impl doesn't use only types from inside the current crate
+   |
+   = note: define and implement a trait or new type instead
+
 error: aborting due to 5 previous errors
 
 Some errors have detailed explanations: E0046, E0117.

diff --git a/tests/ui/const-generics/issues/issue-68366.full.stderr b/tests/ui/const-generics/issues/issue-68366.full.stderr
@@ -1,5 +1,14 @@
+error: `Option<usize>` is forbidden as the type of a const generic parameter
+  --> $DIR/issue-68366.rs:9:25
+   |
+LL | struct Collatz<const N: Option<usize>>;
+   |                         ^^^^^^^^^^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+
 error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/issue-68366.rs:11:7
+  --> $DIR/issue-68366.rs:12:7
    |
 LL | impl <const N: usize> Collatz<{Some(N)}> {}
    |       ^^^^^^^^^^^^^^ unconstrained const parameter
@@ -8,14 +17,25 @@ LL | impl <const N: usize> Collatz<{Some(N)}> {}
    = note: proving the result of expressions other than the parameter are unique is not supported
 
 error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/issue-68366.rs:17:6
+  --> $DIR/issue-68366.rs:19:6
    |
 LL | impl<const N: usize> Foo {}
    |      ^^^^^^^^^^^^^^ unconstrained const parameter
    |
    = note: expressions using a const parameter must map each value to a distinct output value
    = note: proving the result of expressions other than the parameter are unique is not supported
 
-error: aborting due to 2 previous errors
+error: overly complex generic constant
+  --> $DIR/issue-68366.rs:12:31
+   |
+LL | impl <const N: usize> Collatz<{Some(N)}> {}
+   |                               ^-------^
+   |                                |
+   |                                struct/enum construction is not supported in generic constants
+   |
+   = help: consider moving this anonymous constant into a `const` function
+   = note: this operation may be supported in the future
+
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0207`.
diff --git a/tests/ui/const-generics/issues/issue-68366.min.stderr b/tests/ui/const-generics/issues/issue-68366.min.stderr
@@ -1,14 +1,23 @@
 error: generic parameters may not be used in const operations
-  --> $DIR/issue-68366.rs:11:37
+  --> $DIR/issue-68366.rs:12:37
    |
 LL | impl <const N: usize> Collatz<{Some(N)}> {}
    |                                     ^ cannot perform const operation using `N`
    |
    = help: const parameters may only be used as standalone arguments, i.e. `N`
    = help: add `#![feature(generic_const_exprs)]` to allow generic const expressions
 
+error: `Option<usize>` is forbidden as the type of a const generic parameter
+  --> $DIR/issue-68366.rs:9:25
+   |
+LL | struct Collatz<const N: Option<usize>>;
+   |                         ^^^^^^^^^^^^^
+   |
+   = note: the only supported types are integers, `bool` and `char`
+   = help: add `#![feature(adt_const_params)]` to the crate attributes to enable more complex and user defined types
+
 error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/issue-68366.rs:11:7
+  --> $DIR/issue-68366.rs:12:7
    |
 LL | impl <const N: usize> Collatz<{Some(N)}> {}
    |       ^^^^^^^^^^^^^^ unconstrained const parameter
@@ -17,14 +26,14 @@ LL | impl <const N: usize> Collatz<{Some(N)}> {}
    = note: proving the result of expressions other than the parameter are unique is not supported
 
 error[E0207]: the const parameter `N` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/issue-68366.rs:17:6
+  --> $DIR/issue-68366.rs:19:6
    |
 LL | impl<const N: usize> Foo {}
    |      ^^^^^^^^^^^^^^ unconstrained const parameter
    |
    = note: expressions using a const parameter must map each value to a distinct output value
    = note: proving the result of expressions other than the parameter are unique is not supported
 
-error: aborting due to 3 previous errors
+error: aborting due to 4 previous errors
 
 For more information about this error, try `rustc --explain E0207`.
diff --git a/tests/ui/const-generics/issues/issue-68366.rs b/tests/ui/const-generics/issues/issue-68366.rs
@@ -7,10 +7,12 @@
 #![cfg_attr(full, allow(incomplete_features))]
 
 struct Collatz<const N: Option<usize>>;
+//~^ ERROR: `Option<usize>` is forbidden
 
 impl <const N: usize> Collatz<{Some(N)}> {}
 //~^ ERROR the const parameter
 //[min]~^^ generic parameters may not be used in const operations
+//[full]~^^^ ERROR overly complex
 
 struct Foo;
 

diff --git a/tests/ui/duplicate/duplicate-type-parameter.rs b/tests/ui/duplicate/duplicate-type-parameter.rs
@@ -23,7 +23,6 @@ trait Qux<T,T> {}
 
 impl<T,T> Qux<T,T> for Option<T> {}
 //~^ ERROR the name `T` is already used
-//~^^ ERROR the type parameter `T` is not constrained
 
 fn main() {
 }
diff --git a/tests/ui/duplicate/duplicate-type-parameter.stderr b/tests/ui/duplicate/duplicate-type-parameter.stderr
@@ -54,13 +54,6 @@ LL | impl<T,T> Qux<T,T> for Option<T> {}
    |      |
    |      first use of `T`
 
-error[E0207]: the type parameter `T` is not constrained by the impl trait, self type, or predicates
-  --> $DIR/duplicate-type-parameter.rs:24:8
-   |
-LL | impl<T,T> Qux<T,T> for Option<T> {}
-   |        ^ unconstrained type parameter
-
-error: aborting due to 8 previous errors
+error: aborting due to 7 previous errors
 
-Some errors have detailed explanations: E0207, E0403.
-For more information about an error, try `rustc --explain E0207`.
+For more information about this error, try `rustc --explain E0403`.