Always evaluate free constants and statics, even if previous errors occurred

Author: oli-obk

compiler/rustc_hir_analysis/src/lib.rs

@@ -194,6 +194,15 @@ pub fn check_crate(tcx: TyCtxt<'_>) -> Result<(), ErrorGuaranteed> {
         collect::test_opaque_hidden_types(tcx)?;
     }
 
+    tcx.hir().par_body_owners(|item_def_id| {
+        let def_kind = tcx.def_kind(item_def_id);
+        match def_kind {
+            DefKind::Static(_) => tcx.ensure().eval_static_initializer(item_def_id.into()),
+            DefKind::Const => tcx.ensure().const_eval_poly(item_def_id.into()),
+            _ => (),
+        }
+    });
+
     // Freeze definitions as we don't add new ones at this point. This improves performance by
     // allowing lock-free access to them.
     tcx.untracked().definitions.freeze();

compiler/rustc_lint/src/builtin.rs

@@ -1542,32 +1542,6 @@ impl<'tcx> LateLintPass<'tcx> for TypeAliasBounds {
     }
 }
 
-declare_lint_pass!(
-    /// Lint constants that are erroneous.
-    /// Without this lint, we might not get any diagnostic if the constant is
-    /// unused within this crate, even though downstream crates can't use it
-    /// without producing an error.
-    UnusedBrokenConst => []
-);
-
-impl<'tcx> LateLintPass<'tcx> for UnusedBrokenConst {
-    fn check_item(&mut self, cx: &LateContext<'_>, it: &hir::Item<'_>) {
-        match it.kind {
-            hir::ItemKind::Const(_, _, body_id) => {
-                let def_id = cx.tcx.hir().body_owner_def_id(body_id).to_def_id();
-                // trigger the query once for all constants since that will already report the errors
-                // FIXME(generic_const_items): Does this work properly with generic const items?
-                cx.tcx.ensure().const_eval_poly(def_id);
-            }
-            hir::ItemKind::Static(_, _, body_id) => {
-                let def_id = cx.tcx.hir().body_owner_def_id(body_id).to_def_id();
-                cx.tcx.ensure().eval_static_initializer(def_id);
-            }
-            _ => {}
-        }
-    }
-}
-
 declare_lint! {
     /// The `trivial_bounds` lint detects trait bounds that don't depend on
     /// any type parameters.

compiler/rustc_lint/src/lib.rs

@@ -212,8 +212,6 @@ late_lint_methods!(
             ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
             InvalidValue: InvalidValue,
             DerefNullPtr: DerefNullPtr,
-            // May Depend on constants elsewhere
-            UnusedBrokenConst: UnusedBrokenConst,
             UnstableFeatures: UnstableFeatures,
             UngatedAsyncFnTrackCaller: UngatedAsyncFnTrackCaller,
             ArrayIntoIter: ArrayIntoIter::default(),

compiler/rustc_middle/src/mir/interpret/queries.rs

@@ -192,6 +192,15 @@ impl<'tcx> TyCtxtAt<'tcx> {
         self,
         def_id: DefId,
     ) -> Result<mir::ConstAllocation<'tcx>, ErrorHandled> {
+        if let Some(def_id) = def_id.as_local() {
+            if let Some(err) = self
+                .mir_borrowck(def_id)
+                .tainted_by_errors
+                .or(self.mir_const_qualif(def_id).tainted_by_errors)
+            {
+                return Err(err.into());
+            }
+        }
         trace!("eval_static_initializer: Need to compute {:?}", def_id);
         assert!(self.is_static(def_id));
         let instance = ty::Instance::mono(*self, def_id);

tests/ui/associated-consts/issue-24949-assoc-const-static-recursion-impl.rs

@@ -4,12 +4,12 @@ trait Foo {
     const BAR: u32;
 }
 
-const IMPL_REF_BAR: u32 = GlobalImplRef::BAR;
+const IMPL_REF_BAR: u32 = GlobalImplRef::BAR; //~ ERROR E0391
 
 struct GlobalImplRef;
 
 impl GlobalImplRef {
-    const BAR: u32 = IMPL_REF_BAR; //~ ERROR E0391
+    const BAR: u32 = IMPL_REF_BAR;
 }
 
 fn main() {}

tests/ui/associated-consts/issue-24949-assoc-const-static-recursion-impl.stderr

@@ -1,14 +1,9 @@
-error[E0391]: cycle detected when elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 11:19>::BAR`
-  --> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:12:22
-   |
-LL |     const BAR: u32 = IMPL_REF_BAR;
-   |                      ^^^^^^^^^^^^
-   |
-note: ...which requires simplifying constant for the type system `IMPL_REF_BAR`...
+error[E0391]: cycle detected when simplifying constant for the type system `IMPL_REF_BAR`
   --> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:7:1
    |
 LL | const IMPL_REF_BAR: u32 = GlobalImplRef::BAR;
    | ^^^^^^^^^^^^^^^^^^^^^^^
+   |
 note: ...which requires const-evaluating + checking `IMPL_REF_BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:7:27
    |
@@ -29,7 +24,12 @@ note: ...which requires caching mir of `<impl at $DIR/issue-24949-assoc-const-st
    |
 LL |     const BAR: u32 = IMPL_REF_BAR;
    |     ^^^^^^^^^^^^^^
-   = note: ...which again requires elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 11:19>::BAR`, completing the cycle
+note: ...which requires elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 11:19>::BAR`...
+  --> $DIR/issue-24949-assoc-const-static-recursion-impl.rs:12:22
+   |
+LL |     const BAR: u32 = IMPL_REF_BAR;
+   |                      ^^^^^^^^^^^^
+   = note: ...which again requires simplifying constant for the type system `IMPL_REF_BAR`, completing the cycle
    = note: cycle used when running analysis passes on this crate
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 

tests/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait-default.stderr

@@ -1,9 +1,14 @@
-error[E0391]: cycle detected when elaborating drops for `FooDefault::BAR`
+error[E0391]: cycle detected when caching mir of `FooDefault::BAR` for CTFE
+  --> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:5
+   |
+LL |     const BAR: u32 = DEFAULT_REF_BAR;
+   |     ^^^^^^^^^^^^^^
+   |
+note: ...which requires elaborating drops for `FooDefault::BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:22
    |
 LL |     const BAR: u32 = DEFAULT_REF_BAR;
    |                      ^^^^^^^^^^^^^^^
-   |
 note: ...which requires simplifying constant for the type system `DEFAULT_REF_BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:11:1
    |
@@ -24,13 +29,12 @@ note: ...which requires const-evaluating + checking `FooDefault::BAR`...
    |
 LL |     const BAR: u32 = DEFAULT_REF_BAR;
    |     ^^^^^^^^^^^^^^
-note: ...which requires caching mir of `FooDefault::BAR` for CTFE...
+   = note: ...which again requires caching mir of `FooDefault::BAR` for CTFE, completing the cycle
+note: cycle used when const-evaluating + checking `FooDefault::BAR`
   --> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:5
    |
 LL |     const BAR: u32 = DEFAULT_REF_BAR;
    |     ^^^^^^^^^^^^^^
-   = note: ...which again requires elaborating drops for `FooDefault::BAR`, completing the cycle
-   = note: cycle used when running analysis passes on this crate
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 
 error: aborting due to 1 previous error

tests/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait.rs

@@ -4,12 +4,12 @@ trait Foo {
     const BAR: u32;
 }
 
-const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR;
+const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR; //~ ERROR E0391
 
 struct GlobalTraitRef;
 
 impl Foo for GlobalTraitRef {
-    const BAR: u32 = TRAIT_REF_BAR; //~ ERROR E0391
+    const BAR: u32 = TRAIT_REF_BAR;
 }
 
 fn main() {}

tests/ui/associated-consts/issue-24949-assoc-const-static-recursion-trait.stderr

@@ -1,14 +1,9 @@
-error[E0391]: cycle detected when elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 11:28>::BAR`
-  --> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:12:22
-   |
-LL |     const BAR: u32 = TRAIT_REF_BAR;
-   |                      ^^^^^^^^^^^^^
-   |
-note: ...which requires simplifying constant for the type system `TRAIT_REF_BAR`...
+error[E0391]: cycle detected when simplifying constant for the type system `TRAIT_REF_BAR`
   --> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:7:1
    |
 LL | const TRAIT_REF_BAR: u32 = <GlobalTraitRef>::BAR;
    | ^^^^^^^^^^^^^^^^^^^^^^^^
+   |
 note: ...which requires const-evaluating + checking `TRAIT_REF_BAR`...
   --> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:7:28
    |
@@ -29,7 +24,12 @@ note: ...which requires caching mir of `<impl at $DIR/issue-24949-assoc-const-st
    |
 LL |     const BAR: u32 = TRAIT_REF_BAR;
    |     ^^^^^^^^^^^^^^
-   = note: ...which again requires elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 11:28>::BAR`, completing the cycle
+note: ...which requires elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 11:28>::BAR`...
+  --> $DIR/issue-24949-assoc-const-static-recursion-trait.rs:12:22
+   |
+LL |     const BAR: u32 = TRAIT_REF_BAR;
+   |                      ^^^^^^^^^^^^^
+   = note: ...which again requires simplifying constant for the type system `TRAIT_REF_BAR`, completing the cycle
    = note: cycle used when running analysis passes on this crate
    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
 

tests/ui/check-static-immutable-mut-slices.rs

@@ -2,5 +2,6 @@
 
 static TEST: &'static mut [isize] = &mut [];
 //~^ ERROR mutable references are not allowed
+//~| ERROR undefined behavior to use this value
 
 pub fn main() { }