Prevent Deduplication of LongRunningWarn

rust-lang · Sep 21, 2024 · 669f610 · 669f610
1 parent a35da65
commit 669f610
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Showing 3 changed files with 83 additions and 2 deletions.
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -641,7 +641,14 @@ impl<'tcx> interpret::Machine<'tcx> for CompileTimeMachine<'tcx> {
  // current number of evaluated terminators is a power of 2. The latter gives us a cheap
  // way to implement exponential backoff.
  let span = ecx.cur_span();
- ecx.tcx.dcx().emit_warn(LongRunningWarn { span, item_span: ecx.tcx.span });
+ // We store a unique number in `force_duplicate` to evade `-Z deduplicate-diagnostics`.
+ // `new_steps` is guaranteed to be unique because `ecx.machine.num_evaluated_steps` is
+ // always increasing.
+ ecx.tcx.dcx().emit_warn(LongRunningWarn {
+ span,
+ item_span: ecx.tcx.span,
+ force_duplicate: new_steps,
+ });
  }
  }
 

diff --git a/compiler/rustc_const_eval/src/errors.rs b/compiler/rustc_const_eval/src/errors.rs
@@ -243,6 +243,8 @@ pub struct LongRunningWarn {
  pub span: Span,
  #[help]
  pub item_span: Span,
+ // Used for evading `-Z deduplicate-diagnostics`.
+ pub force_duplicate: usize,
 }
 
 #[derive(Subdiagnostic)]

diff --git a/tests/ui/consts/const-eval/stable-metric/evade-deduplication-issue-118612.stderr b/tests/ui/consts/const-eval/stable-metric/evade-deduplication-issue-118612.stderr
@@ -16,5 +16,77 @@ help: the constant being evaluated
 LL | const FOO: () = {
  | ^^^^^^^^^^^^^
 
-warning: 1 warning emitted
+warning: constant evaluation is taking a long time
+ --> $DIR/evade-deduplication-issue-118612.rs:8:5
+ |
+LL | / loop {
+LL | |
+LL | |
+LL | |
+... |
+LL | | }
+LL | | }
+ | |_____^ the const evaluator is currently interpreting this expression
+ |
+help: the constant being evaluated
+ --> $DIR/evade-deduplication-issue-118612.rs:6:1
+ |
+LL | const FOO: () = {
+ | ^^^^^^^^^^^^^
+
+warning: constant evaluation is taking a long time
+ --> $DIR/evade-deduplication-issue-118612.rs:8:5
+ |
+LL | / loop {
+LL | |
+LL | |
+LL | |
+... |
+LL | | }
+LL | | }
+ | |_____^ the const evaluator is currently interpreting this expression
+ |
+help: the constant being evaluated
+ --> $DIR/evade-deduplication-issue-118612.rs:6:1
+ |
+LL | const FOO: () = {
+ | ^^^^^^^^^^^^^
+
+warning: constant evaluation is taking a long time
+ --> $DIR/evade-deduplication-issue-118612.rs:8:5
+ |
+LL | / loop {
+LL | |
+LL | |
+LL | |
+... |
+LL | | }
+LL | | }
+ | |_____^ the const evaluator is currently interpreting this expression
+ |
+help: the constant being evaluated
+ --> $DIR/evade-deduplication-issue-118612.rs:6:1
+ |
+LL | const FOO: () = {
+ | ^^^^^^^^^^^^^
+
+warning: constant evaluation is taking a long time
+ --> $DIR/evade-deduplication-issue-118612.rs:8:5
+ |
+LL | / loop {
+LL | |
+LL | |
+LL | |
+... |
+LL | | }
+LL | | }
+ | |_____^ the const evaluator is currently interpreting this expression
+ |
+help: the constant being evaluated
+ --> $DIR/evade-deduplication-issue-118612.rs:6:1
+ |
+LL | const FOO: () = {
+ | ^^^^^^^^^^^^^
+
+warning: 5 warnings emitted