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

Author: oli-obk

compiler/rustc_const_eval/src/transform/check_consts/check.rs

@@ -249,7 +249,7 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
         let secondary_errors = mem::take(&mut self.secondary_errors);
         if self.error_emitted.is_none() {
             for error in secondary_errors {
-                error.emit();
+                self.error_emitted = Some(error.emit());
             }
         } else {
             assert!(self.tcx.dcx().has_errors().is_some());

compiler/rustc_hir_analysis/src/lib.rs

@@ -196,6 +196,17 @@ pub fn check_crate(tcx: TyCtxt<'_>) -> Result<(), ErrorGuaranteed> {
         collect::test_opaque_hidden_types(tcx)?;
     }
 
+    // Make sure we evaluate all static and (non-associated) const items, even if unused.
+    // If any of these fail to evaluate, we do not want this crate to pass compilation.
+    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),
+            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(),

src/tools/clippy/tests/ui-toml/suppress_lint_in_const/test.rs

@@ -13,8 +13,6 @@
 
 const ARR: [i32; 2] = [1, 2];
 const REF: &i32 = &ARR[idx()]; // Ok, should not produce stderr, since `suppress-restriction-lint-in-const` is set true.
-const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
-//~^ ERROR: failed
 
 const fn idx() -> usize {
     1
@@ -35,9 +33,6 @@ fn main() {
     x[const { idx() }]; // Ok, should not produce stderr.
     x[const { idx4() }]; // Ok, let rustc's `unconditional_panic` lint handle `usize` indexing on arrays.
     const { &ARR[idx()] }; // Ok, should not produce stderr, since `suppress-restriction-lint-in-const` is set true.
-    const { &ARR[idx4()] }; // Ok, should not produce stderr, since `suppress-restriction-lint-in-const` is set true.
-    //
-    //~^^ ERROR: failed
 
     let y = &x;
     y[0]; // Ok, referencing shouldn't affect this lint. See the issue 6021

src/tools/clippy/tests/ui-toml/suppress_lint_in_const/test.stderr

@@ -1,17 +1,5 @@
-error[E0080]: evaluation of `main::{constant#3}` failed
-  --> $DIR/test.rs:38:14
-   |
-LL |     const { &ARR[idx4()] }; // Ok, should not produce stderr, since `suppress-restriction-lint-in-const` is set true.
-   |              ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4
-
-note: erroneous constant encountered
-  --> $DIR/test.rs:38:5
-   |
-LL |     const { &ARR[idx4()] }; // Ok, should not produce stderr, since `suppress-restriction-lint-in-const` is set true.
-   |     ^^^^^^^^^^^^^^^^^^^^^^
-
 error: indexing may panic
-  --> $DIR/test.rs:29:5
+  --> $DIR/test.rs:27:5
    |
 LL |     x[index];
    |     ^^^^^^^^
@@ -21,51 +9,44 @@ LL |     x[index];
    = help: to override `-D warnings` add `#[allow(clippy::indexing_slicing)]`
 
 error: indexing may panic
-  --> $DIR/test.rs:47:5
+  --> $DIR/test.rs:42:5
    |
 LL |     v[0];
    |     ^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: indexing may panic
-  --> $DIR/test.rs:48:5
+  --> $DIR/test.rs:43:5
    |
 LL |     v[10];
    |     ^^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: indexing may panic
-  --> $DIR/test.rs:49:5
+  --> $DIR/test.rs:44:5
    |
 LL |     v[1 << 3];
    |     ^^^^^^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: indexing may panic
-  --> $DIR/test.rs:55:5
+  --> $DIR/test.rs:50:5
    |
 LL |     v[N];
    |     ^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: indexing may panic
-  --> $DIR/test.rs:56:5
+  --> $DIR/test.rs:51:5
    |
 LL |     v[M];
    |     ^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
-error[E0080]: evaluation of constant value failed
-  --> $DIR/test.rs:16:24
-   |
-LL | const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
-   |                        ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4
-
-error: aborting due to 8 previous errors
+error: aborting due to 6 previous errors
 
-For more information about this error, try `rustc --explain E0080`.

src/tools/clippy/tests/ui/indexing_slicing_index.rs

@@ -13,8 +13,6 @@
 const ARR: [i32; 2] = [1, 2];
 const REF: &i32 = &ARR[idx()]; // This should be linted, since `suppress-restriction-lint-in-const` default is false.
 //~^ ERROR: indexing may panic
-const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
-//~^ ERROR: indexing may panic
 
 const fn idx() -> usize {
     1

src/tools/clippy/tests/ui/indexing_slicing_index.stderr

@@ -9,37 +9,28 @@ LL | const REF: &i32 = &ARR[idx()]; // This should be linted, since `suppress-re
    = note: `-D clippy::indexing-slicing` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::indexing_slicing)]`
 
-error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:16:24
-   |
-LL | const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
-   |                        ^^^^^^^^^^^
-   |
-   = help: consider using `.get(n)` or `.get_mut(n)` instead
-   = note: the suggestion might not be applicable in constant blocks
-
 error[E0080]: evaluation of `main::{constant#3}` failed
-  --> $DIR/indexing_slicing_index.rs:48:14
+  --> $DIR/indexing_slicing_index.rs:46:14
    |
 LL |     const { &ARR[idx4()] };
    |              ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4
 
 note: erroneous constant encountered
-  --> $DIR/indexing_slicing_index.rs:48:5
+  --> $DIR/indexing_slicing_index.rs:46:5
    |
 LL |     const { &ARR[idx4()] };
    |     ^^^^^^^^^^^^^^^^^^^^^^
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:29:5
+  --> $DIR/indexing_slicing_index.rs:27:5
    |
 LL |     x[index];
    |     ^^^^^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: index is out of bounds
-  --> $DIR/indexing_slicing_index.rs:32:5
+  --> $DIR/indexing_slicing_index.rs:30:5
    |
 LL |     x[4];
    |     ^^^^
@@ -48,13 +39,13 @@ LL |     x[4];
    = help: to override `-D warnings` add `#[allow(clippy::out_of_bounds_indexing)]`
 
 error: index is out of bounds
-  --> $DIR/indexing_slicing_index.rs:34:5
+  --> $DIR/indexing_slicing_index.rs:32:5
    |
 LL |     x[1 << 3];
    |     ^^^^^^^^^
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:45:14
+  --> $DIR/indexing_slicing_index.rs:43:14
    |
 LL |     const { &ARR[idx()] };
    |              ^^^^^^^^^^
@@ -63,7 +54,7 @@ LL |     const { &ARR[idx()] };
    = note: the suggestion might not be applicable in constant blocks
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:48:14
+  --> $DIR/indexing_slicing_index.rs:46:14
    |
 LL |     const { &ARR[idx4()] };
    |              ^^^^^^^^^^^
@@ -72,69 +63,63 @@ LL |     const { &ARR[idx4()] };
    = note: the suggestion might not be applicable in constant blocks
 
 error: index is out of bounds
-  --> $DIR/indexing_slicing_index.rs:55:5
+  --> $DIR/indexing_slicing_index.rs:53:5
    |
 LL |     y[4];
    |     ^^^^
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:58:5
+  --> $DIR/indexing_slicing_index.rs:56:5
    |
 LL |     v[0];
    |     ^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:60:5
+  --> $DIR/indexing_slicing_index.rs:58:5
    |
 LL |     v[10];
    |     ^^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:62:5
+  --> $DIR/indexing_slicing_index.rs:60:5
    |
 LL |     v[1 << 3];
    |     ^^^^^^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: index is out of bounds
-  --> $DIR/indexing_slicing_index.rs:70:5
+  --> $DIR/indexing_slicing_index.rs:68:5
    |
 LL |     x[N];
    |     ^^^^
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:73:5
+  --> $DIR/indexing_slicing_index.rs:71:5
    |
 LL |     v[N];
    |     ^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: indexing may panic
-  --> $DIR/indexing_slicing_index.rs:75:5
+  --> $DIR/indexing_slicing_index.rs:73:5
    |
 LL |     v[M];
    |     ^^^^
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
 
 error: index is out of bounds
-  --> $DIR/indexing_slicing_index.rs:79:13
+  --> $DIR/indexing_slicing_index.rs:77:13
    |
 LL |     let _ = x[4];
    |             ^^^^
 
-error[E0080]: evaluation of constant value failed
-  --> $DIR/indexing_slicing_index.rs:16:24
-   |
-LL | const REF_ERR: &i32 = &ARR[idx4()]; // Ok, let rustc handle const contexts.
-   |                        ^^^^^^^^^^^ index out of bounds: the length is 2 but the index is 4
-
-error: aborting due to 17 previous errors
+error: aborting due to 15 previous errors
 
 For more information about this error, try `rustc --explain E0080`.

src/tools/miri/tests/fail/stacked_borrows/static_memory_modification.rs

@@ -3,6 +3,6 @@ static X: usize = 5;
 #[allow(mutable_transmutes)]
 fn main() {
     let _x = unsafe {
-        std::mem::transmute::<&usize, &mut usize>(&X) //~ ERROR: writing to alloc1 which is read-only
+        std::mem::transmute::<&usize, &mut usize>(&X) //~ ERROR: writing to alloc2 which is read-only
     };
 }

tests/mir-opt/dataflow-const-prop/enum.rs

@@ -62,7 +62,7 @@ fn statics() {
 
     static RC: &E = &E::V2(4);
 
-    // CHECK: [[t:_.*]] = const {alloc2: &&E};
+    // CHECK: [[t:_.*]] = const {alloc5: &&E};
     // CHECK: [[e2]] = (*[[t]]);
     let e2 = RC;