Rollup merge of rust-lang#149183 - tiif:typing_env_fix, r=BoxyUwU

Use `TypingMode::PostAnalysis` in `try_evaluate_const`

As mentioned in rust-lang#148698 (comment), we should use ``TypingMode::PostAnalysis`` for that path.

`@BoxyUwU` prefer the match in ``try_evaluate_const`` to be exhaustive, so I also included that in this PR :3

Author: Zalathar

compiler/rustc_trait_selection/src/traits/mod.rs

@@ -681,7 +681,7 @@ pub fn try_evaluate_const<'tcx>(
 
                     (args, typing_env)
                 }
-                _ => {
+                Some(ty::AnonConstKind::MCG) | Some(ty::AnonConstKind::NonTypeSystem) | None => {
                     // We are only dealing with "truly" generic/uninferred constants here:
                     // - GCEConsts have been handled separately
                     // - Repeat expr count back compat consts have also been handled separately
@@ -700,7 +700,7 @@ pub fn try_evaluate_const<'tcx>(
 
                     // Since there is no generic parameter, we can just drop the environment
                     // to prevent query cycle.
-                    let typing_env = infcx.typing_env(ty::ParamEnv::empty());
+                    let typing_env = ty::TypingEnv::fully_monomorphized();
 
                     (uv.args, typing_env)
                 }