Auto merge of rust-lang#120687 - oli-obk:early_const_prop, r=<try>

Run const_prop_lint in check builds, too

implements rust-lang#108730 (comment)

Turns the const_prop_lint pass into a query that is run alongside borrowck.

Author: bors

compiler/rustc_abi/src/layout.rs

@@ -426,10 +426,11 @@ where
                 }
             }
         }
-        _ => assert!(
-            start == Bound::Unbounded && end == Bound::Unbounded,
-            "nonscalar layout for layout_scalar_valid_range type: {st:#?}",
-        ),
+        _ => {
+            if start != Bound::Unbounded || end != Bound::Unbounded {
+                return None;
+            }
+        }
     }
 
     Some(st)

compiler/rustc_interface/src/passes.rs

@@ -738,6 +738,7 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
             // Run unsafety check because it's responsible for stealing and
             // deallocating THIR.
             tcx.ensure().check_unsafety(def_id);
+            tcx.ensure().const_prop_lint(def_id);
             tcx.ensure().mir_borrowck(def_id)
         });
     });

compiler/rustc_middle/src/query/mod.rs

@@ -1013,6 +1013,12 @@ rustc_queries! {
         cache_on_disk_if(tcx) { tcx.is_typeck_child(key.to_def_id()) }
     }
 
+    /// Run the const prop lints on the `mir_promoted` of an item.
+    query const_prop_lint(key: LocalDefId) {
+        desc { |tcx| "checking const prop lints for `{}`", tcx.def_path_str(key) }
+        cache_on_disk_if { true }
+    }
+
     /// Gets a complete map from all types to their inherent impls.
     /// Not meant to be used directly outside of coherence.
     query crate_inherent_impls(k: ()) -> Result<&'tcx CrateInherentImpls, ErrorGuaranteed> {

compiler/rustc_mir_transform/src/lib.rs

@@ -142,6 +142,7 @@ pub fn provide(providers: &mut Providers) {
         is_ctfe_mir_available: |tcx, did| is_mir_available(tcx, did),
         mir_callgraph_reachable: inline::cycle::mir_callgraph_reachable,
         mir_inliner_callees: inline::cycle::mir_inliner_callees,
+        const_prop_lint,
         promoted_mir,
         deduced_param_attrs: deduce_param_attrs::deduced_param_attrs,
         ..*providers
@@ -394,6 +395,27 @@ fn inner_mir_for_ctfe(tcx: TyCtxt<'_>, def: LocalDefId) -> Body<'_> {
     body
 }
 
+fn const_prop_lint(tcx: TyCtxt<'_>, def: LocalDefId) {
+    let (body, _) = tcx.mir_promoted(def);
+    let body = body.borrow();
+
+    let mir_borrowck = tcx.mir_borrowck(def);
+
+    // If there are impossible bounds on the body being const prop linted,
+    // the const eval logic used in const prop may ICE unexpectedly.
+    let predicates = tcx
+        .predicates_of(body.source.def_id())
+        .predicates
+        .iter()
+        .filter_map(|(p, _)| if p.is_global() { Some(*p) } else { None });
+    if !traits::impossible_predicates(tcx, traits::elaborate(tcx, predicates).collect())
+        && mir_borrowck.tainted_by_errors.is_none()
+        && body.tainted_by_errors.is_none()
+    {
+        const_prop_lint::ConstPropLint.run_lint(tcx, &body);
+    }
+}
+
 /// Obtain just the main MIR (no promoteds) and run some cleanups on it. This also runs
 /// mir borrowck *before* doing so in order to ensure that borrowck can be run and doesn't
 /// end up missing the source MIR due to stealing happening.
@@ -402,6 +424,7 @@ fn mir_drops_elaborated_and_const_checked(tcx: TyCtxt<'_>, def: LocalDefId) -> &
         tcx.ensure_with_value().mir_coroutine_witnesses(def);
     }
     let mir_borrowck = tcx.mir_borrowck(def);
+    tcx.ensure().const_prop_lint(def);
 
     let is_fn_like = tcx.def_kind(def).is_fn_like();
     if is_fn_like {
@@ -534,7 +557,6 @@ fn run_runtime_lowering_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
         &elaborate_box_derefs::ElaborateBoxDerefs,
         &coroutine::StateTransform,
         &add_retag::AddRetag,
-        &Lint(const_prop_lint::ConstPropLint),
     ];
     pm::run_passes_no_validate(tcx, body, passes, Some(MirPhase::Runtime(RuntimePhase::Initial)));
 }

tests/ui/array-slice-vec/array_const_index-0.stderr

@@ -4,6 +4,20 @@ error[E0080]: evaluation of constant value failed
 LL | const B: i32 = (&A)[1];
    |                ^^^^^^^ index out of bounds: the length is 0 but the index is 1
 
+note: erroneous constant encountered
+  --> $DIR/array_const_index-0.rs:7:13
+   |
+LL |     let _ = B;
+   |             ^
+
+note: erroneous constant encountered
+  --> $DIR/array_const_index-0.rs:7:13
+   |
+LL |     let _ = B;
+   |             ^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0080`.

tests/ui/array-slice-vec/array_const_index-1.stderr

@@ -4,6 +4,20 @@ error[E0080]: evaluation of constant value failed
 LL | const B: i32 = A[1];
    |                ^^^^ index out of bounds: the length is 0 but the index is 1
 
+note: erroneous constant encountered
+  --> $DIR/array_const_index-1.rs:7:13
+   |
+LL |     let _ = B;
+   |             ^
+
+note: erroneous constant encountered
+  --> $DIR/array_const_index-1.rs:7:13
+   |
+LL |     let _ = B;
+   |             ^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 error: aborting due to 1 previous error
 
 For more information about this error, try `rustc --explain E0080`.

tests/ui/associated-consts/defaults-cyclic-fail.rs

@@ -1,5 +1,3 @@
-// build-fail
-
 // Cyclic assoc. const defaults don't error unless *used*
 trait Tr {
     const A: u8 = Self::B;

tests/ui/associated-consts/defaults-cyclic-fail.stderr

@@ -1,27 +1,27 @@
 error[E0391]: cycle detected when simplifying constant for the type system `Tr::A`
-  --> $DIR/defaults-cyclic-fail.rs:5:5
+  --> $DIR/defaults-cyclic-fail.rs:3:5
    |
 LL |     const A: u8 = Self::B;
    |     ^^^^^^^^^^^
    |
 note: ...which requires const-evaluating + checking `Tr::A`...
-  --> $DIR/defaults-cyclic-fail.rs:5:19
+  --> $DIR/defaults-cyclic-fail.rs:3:19
    |
 LL |     const A: u8 = Self::B;
    |                   ^^^^^^^
 note: ...which requires simplifying constant for the type system `Tr::B`...
-  --> $DIR/defaults-cyclic-fail.rs:8:5
+  --> $DIR/defaults-cyclic-fail.rs:6:5
    |
 LL |     const B: u8 = Self::A;
    |     ^^^^^^^^^^^
 note: ...which requires const-evaluating + checking `Tr::B`...
-  --> $DIR/defaults-cyclic-fail.rs:8:19
+  --> $DIR/defaults-cyclic-fail.rs:6:19
    |
 LL |     const B: u8 = Self::A;
    |                   ^^^^^^^
    = note: ...which again requires simplifying constant for the type system `Tr::A`, completing the cycle
 note: cycle used when const-evaluating + checking `main::promoted[1]`
-  --> $DIR/defaults-cyclic-fail.rs:16:16
+  --> $DIR/defaults-cyclic-fail.rs:14:16
    |
 LL |     assert_eq!(<() as Tr>::A, 0);
    |                ^^^^^^^^^^^^^

tests/ui/associated-consts/defaults-not-assumed-fail.rs

@@ -1,5 +1,3 @@
-// build-fail
-
 trait Tr {
     const A: u8 = 255;
 

tests/ui/associated-consts/defaults-not-assumed-fail.stderr

@@ -1,25 +1,25 @@
 error[E0080]: evaluation of `<() as Tr>::B` failed
-  --> $DIR/defaults-not-assumed-fail.rs:8:19
+  --> $DIR/defaults-not-assumed-fail.rs:6:19
    |
 LL |     const B: u8 = Self::A + 1;
    |                   ^^^^^^^^^^^ attempt to compute `u8::MAX + 1_u8`, which would overflow
 
 note: erroneous constant encountered
-  --> $DIR/defaults-not-assumed-fail.rs:33:16
+  --> $DIR/defaults-not-assumed-fail.rs:31:16
    |
 LL |     assert_eq!(<() as Tr>::B, 0);    // causes the error above
    |                ^^^^^^^^^^^^^
 
 note: erroneous constant encountered
-  --> $DIR/defaults-not-assumed-fail.rs:33:5
+  --> $DIR/defaults-not-assumed-fail.rs:31:5
    |
 LL |     assert_eq!(<() as Tr>::B, 0);    // causes the error above
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: this note originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 note: erroneous constant encountered
-  --> $DIR/defaults-not-assumed-fail.rs:33:5
+  --> $DIR/defaults-not-assumed-fail.rs:31:5
    |
 LL |     assert_eq!(<() as Tr>::B, 0);    // causes the error above
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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

@@ -1,4 +1,4 @@
-error[E0391]: cycle detected when elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 11:19>::BAR`
+error[E0391]: cycle detected when checking const prop lints 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;
@@ -29,7 +29,12 @@ 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:12:5
+   |
+LL |     const BAR: u32 = IMPL_REF_BAR;
+   |     ^^^^^^^^^^^^^^
+   = note: ...which again requires checking const prop lints for `<impl at $DIR/issue-24949-assoc-const-static-recursion-impl.rs:11:1: 11:19>::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

@@ -1,4 +1,4 @@
-error[E0391]: cycle detected when elaborating drops for `FooDefault::BAR`
+error[E0391]: cycle detected when checking const prop lints for `FooDefault::BAR`
   --> $DIR/issue-24949-assoc-const-static-recursion-trait-default.rs:8:22
    |
 LL |     const BAR: u32 = DEFAULT_REF_BAR;
@@ -29,7 +29,12 @@ note: ...which requires caching mir of `FooDefault::BAR` for CTFE...
    |
 LL |     const BAR: u32 = DEFAULT_REF_BAR;
    |     ^^^^^^^^^^^^^^
-   = note: ...which again requires elaborating drops for `FooDefault::BAR`, completing the cycle
+note: ...which requires elaborating drops for `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 checking const prop lints 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
 

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

@@ -1,4 +1,4 @@
-error[E0391]: cycle detected when elaborating drops for `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 11:28>::BAR`
+error[E0391]: cycle detected when checking const prop lints 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;
@@ -29,7 +29,12 @@ 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:12:5
+   |
+LL |     const BAR: u32 = TRAIT_REF_BAR;
+   |     ^^^^^^^^^^^^^^
+   = note: ...which again requires checking const prop lints for `<impl at $DIR/issue-24949-assoc-const-static-recursion-trait.rs:11:1: 11:28>::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/async-await/in-trait/indirect-recursion-issue-112047.rs

@@ -1,8 +1,5 @@
 // edition: 2021
 
-// Test doesn't fail until monomorphization time, unfortunately.
-// build-fail
-
 fn main() {
     let _ = async {
         A.first().await.second().await;

tests/ui/async-await/in-trait/indirect-recursion-issue-112047.stderr

@@ -1,5 +1,5 @@
 error[E0733]: recursion in an async fn requires boxing
-  --> $DIR/indirect-recursion-issue-112047.rs:34:5
+  --> $DIR/indirect-recursion-issue-112047.rs:31:5
    |
 LL |     async fn second(self) {
    |     ^^^^^^^^^^^^^^^^^^^^^

tests/ui/coherence/occurs-check/opaques.next.stderr

@@ -1,5 +1,5 @@
 error[E0119]: conflicting implementations of trait `Trait<Alias<_>>` for type `Alias<_>`
-  --> $DIR/opaques.rs:29:1
+  --> $DIR/opaques.rs:33:1
    |
 LL | impl<T> Trait<T> for T {
    | ---------------------- first implementation here

tests/ui/coherence/occurs-check/opaques.old.stderr

@@ -0,0 +1,8 @@
+error: internal compiler error: unexpected ambiguity: Canonical { value: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [Binder { value: TraitPredicate(<T as std::marker::Sized>, polarity:Positive), bound_vars: [] }], reveal: All }, value: AliasTy { args: [T/#0, T/#0], def_id: DefId(0:15 ~ opaques[e7ab]::Trait::Assoc) } }, max_universe: U0, variables: [] } Canonical { value: QueryResponse { var_values: CanonicalVarValues { var_values: [] }, region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, certainty: Ambiguous, opaque_types: [], value: NormalizationResult { normalized_ty: ^0 } }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
+   |
+   = error: internal compiler error: unexpected ambiguity: Canonical { value: ParamEnvAnd { param_env: ParamEnv { caller_bounds: [], reveal: All }, value: AliasTy { args: [(), ()], def_id: DefId(0:15 ~ opaques[e7ab]::Trait::Assoc) } }, max_universe: U0, variables: [] } Canonical { value: QueryResponse { var_values: CanonicalVarValues { var_values: [] }, region_constraints: QueryRegionConstraints { outlives: [], member_constraints: [] }, certainty: Ambiguous, opaque_types: [], value: NormalizationResult { normalized_ty: ^0 } }, max_universe: U0, variables: [CanonicalVarInfo { kind: Ty(General(U0)) }] }
+   |
+   = query stack during panic:
+end of query stack
+error: aborting due to 2 previous errors
+

tests/ui/coherence/occurs-check/opaques.rs

@@ -4,7 +4,11 @@
 // A regression test for #105787
 
 //[old] known-bug: #105787
-//[old] check-pass
+//[old] failure-status: 101
+// normalize-stderr-test "note: .*\n\n" -> ""
+// normalize-stderr-test "thread 'rustc' panicked.*\n" -> ""
+// normalize-stderr-test "(error: internal compiler error: [^:]+):\d+:\d+: " -> "$1:LL:CC: "
+// rustc-env:RUST_BACKTRACE=0
 #![feature(type_alias_impl_trait)]
 mod defining_scope {
     use super::*;

tests/ui/const_prop/const-prop-ice.rs

@@ -1,5 +1,3 @@
-// build-fail
-
 fn main() {
     [0; 3][3u64 as usize]; //~ ERROR this operation will panic at runtime
 }

tests/ui/const_prop/const-prop-ice.stderr

@@ -1,5 +1,5 @@
 error: this operation will panic at runtime
-  --> $DIR/const-prop-ice.rs:4:5
+  --> $DIR/const-prop-ice.rs:2:5
    |
 LL |     [0; 3][3u64 as usize];
    |     ^^^^^^^^^^^^^^^^^^^^^ index out of bounds: the length is 3 but the index is 3

tests/ui/const_prop/const-prop-ice2.rs

@@ -1,5 +1,3 @@
-// build-fail
-
 fn main() {
     enum Enum { One=1 }
     let xs=[0;1 as usize];

tests/ui/const_prop/const-prop-ice2.stderr

@@ -1,5 +1,5 @@
 error: this operation will panic at runtime
-  --> $DIR/const-prop-ice2.rs:6:20
+  --> $DIR/const-prop-ice2.rs:4:20
    |
 LL |     println!("{}", xs[Enum::One as usize]);
    |                    ^^^^^^^^^^^^^^^^^^^^^^ index out of bounds: the length is 1 but the index is 1

tests/ui/consts/const-err-early.rs

@@ -10,5 +10,5 @@ fn main() {
     let _c = C;
     let _d = D;
     let _e = E;
-    let _e = [6u8][1];
+    let _e = [6u8][1]; //~ ERROR: will panic at runtime
 }