Rollup merge of #136429 - fmease:gci-fix-def-site-checks, r=BoxyUwU

GCI: At their def site, actually wfcheck the where-clause & always eval free lifetime-generic constants

* 1st commit: Partially addresses [#136204](https://github.com/rust-lang/rust/issues/136204) by turning const eval errors from post to pre-mono for free lifetime-generic constants.
  * As the linked issue/comment states, on master there's a difference between `const _: () = panic!();` (pre-mono error) and `const _<'a>: () = panic!();` (post-mono error) which feels wrong.
  * With this PR, both become pre-mono ones!
* 2nd commit: Oof, yeah, I missed that in the initial impl!

This doesn't fully address #136204 because I still haven't figured out how & where to properly & best suppress const eval of free constants whose predicates don't hold at the def site. The motivating example is `const _UNUSED: () = () where for<'_delay> String: Copy;` which can also be found over at the tracking issue #113521.

r? compiler-errors or reassign

1 files changed, 0 insertions, 22 deletions

diff --git a/compiler/rustc_middle/src/mir/interpret/queries.rs b/compiler/rustc_middle/src/mir/interpret/queries.rs
index 4a5c42c721c..97db45a70d7 100644
--- a/compiler/rustc_middle/src/mir/interpret/queries.rs
+++ b/compiler/rustc_middle/src/mir/interpret/queries.rs
@@ -9,7 +9,6 @@ use super::{
     ReportedErrorInfo,
 };
 use crate::mir;
-use crate::query::TyCtxtEnsureOk;
 use crate::ty::{self, GenericArgs, TyCtxt, TypeVisitableExt};
 
 impl<'tcx> TyCtxt<'tcx> {
@@ -197,24 +196,3 @@ impl<'tcx> TyCtxt<'tcx> {
         }
     }
 }
-
-impl<'tcx> TyCtxtEnsureOk<'tcx> {
-    /// Evaluates a constant without providing any generic parameters. This is useful to evaluate consts
-    /// that can't take any generic arguments like const items or enum discriminants. If a
-    /// generic parameter is used within the constant `ErrorHandled::TooGeneric` will be returned.
-    #[instrument(skip(self), level = "debug")]
-    pub fn const_eval_poly(self, def_id: DefId) {
-        // In some situations def_id will have generic parameters within scope, but they aren't allowed
-        // to be used. So we can't use `Instance::mono`, instead we feed unresolved generic parameters
-        // into `const_eval` which will return `ErrorHandled::TooGeneric` if any of them are
-        // encountered.
-        let args = GenericArgs::identity_for_item(self.tcx, def_id);
-        let instance = ty::Instance::new_raw(def_id, self.tcx.erase_regions(args));
-        let cid = GlobalId { instance, promoted: None };
-        let typing_env = ty::TypingEnv::post_analysis(self.tcx, def_id);
-        // Const-eval shouldn't depend on lifetimes at all, so we can erase them, which should
-        // improve caching of queries.
-        let inputs = self.tcx.erase_regions(typing_env.as_query_input(cid));
-        self.eval_to_const_value_raw(inputs)
-    }
-}