Auto merge of rust-lang#108689 - compiler-errors:normalization-error-smaller, r=lcnr

Remove `NormalizationError::ConstantKind`

No longer in use by `TryNormalizeAfterErasingRegionsFolder` (as of rust-lang#102355 / e8150fa it seems). It's making `LayoutError`, etc. kinda large -- that was noticed by `@zoxc.`

Author: bors

compiler/rustc_middle/src/ty/normalize_erasing_regions.rs

@@ -7,7 +7,6 @@
 //! `normalize_generic_arg_after_erasing_regions` query for each type
 //! or constant found within. (This underlying query is what is cached.)
 
-use crate::mir;
 use crate::traits::query::NoSolution;
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeFolder};
 use crate::ty::{self, EarlyBinder, SubstsRef, Ty, TyCtxt, TypeVisitableExt};
@@ -16,15 +15,13 @@ use crate::ty::{self, EarlyBinder, SubstsRef, Ty, TyCtxt, TypeVisitableExt};
 pub enum NormalizationError<'tcx> {
     Type(Ty<'tcx>),
     Const(ty::Const<'tcx>),
-    ConstantKind(mir::ConstantKind<'tcx>),
 }
 
 impl<'tcx> NormalizationError<'tcx> {
     pub fn get_type_for_failure(&self) -> String {
         match self {
             NormalizationError::Type(t) => format!("{}", t),
             NormalizationError::Const(c) => format!("{}", c),
-            NormalizationError::ConstantKind(ck) => format!("{}", ck),
         }
     }
 }