Auto merge of #93691 - compiler-errors:mir-tainted-by-errors, r=oli-obk

Implement `tainted_by_errors` in MIR borrowck, use it to skip CTFE

Putting this up for initial review. The issue that I found is when we're evaluating a const, we're doing borrowck, but doing nothing with the fact that borrowck fails.

This implements a `tainted_by_errors` field for MIR borrowck like we have in infcx, so we can use that information to return an `Err` during const eval if our const fails to borrowck.

This PR needs some cleaning up. I should probably just use `Result` in more places, instead of `.expect`ing in the places I am, but I just wanted it to compile so I could see if it worked!

Fixes #93646

r? `@oli-obk`
feel free to reassign

1 files changed, 5 insertions, 2 deletions

diff --git a/compiler/rustc_mir_build/src/build/mod.rs b/compiler/rustc_mir_build/src/build/mod.rs
index 88d994e32fe..10807d43276 100644
--- a/compiler/rustc_mir_build/src/build/mod.rs
+++ b/compiler/rustc_mir_build/src/build/mod.rs
@@ -104,8 +104,8 @@ fn mir_build(tcx: TyCtxt<'_>, def: ty::WithOptConstParam<LocalDefId>) -> Body<'_
     let span_with_body = span_with_body.unwrap_or_else(|| tcx.hir().span(id));
 
     tcx.infer_ctxt().enter(|infcx| {
-        let body = if let Some(ErrorReported) = typeck_results.tainted_by_errors {
-            build::construct_error(&infcx, def, id, body_id, body_owner_kind)
+        let body = if let Some(error_reported) = typeck_results.tainted_by_errors {
+            build::construct_error(&infcx, def, id, body_id, body_owner_kind, error_reported)
         } else if body_owner_kind.is_fn_or_closure() {
             // fetch the fully liberated fn signature (that is, all bound
             // types/lifetimes replaced)
@@ -715,6 +715,7 @@ fn construct_error<'a, 'tcx>(
     hir_id: hir::HirId,
     body_id: hir::BodyId,
     body_owner_kind: hir::BodyOwnerKind,
+    err: ErrorReported,
 ) -> Body<'tcx> {
     let tcx = infcx.tcx;
     let span = tcx.hir().span(hir_id);
@@ -769,6 +770,7 @@ fn construct_error<'a, 'tcx>(
         vec![],
         span,
         generator_kind,
+        Some(err),
     );
     body.generator.as_mut().map(|gen| gen.yield_ty = Some(ty));
     body
@@ -857,6 +859,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
             self.var_debug_info,
             self.fn_span,
             self.generator_kind,
+            self.typeck_results.tainted_by_errors,
         )
     }