Rollup merge of #130990 - RalfJung:mir-const-normalize, r=compiler-errors

try to get rid of mir::Const::normalize

It was easy to make this compile, let's see if anything breaks...

r? `@compiler-errors`

compiler/rustc_middle/src/mir/consts.rs

@@ -221,7 +221,9 @@ pub enum Const<'tcx> {
 }
 
 impl<'tcx> Const<'tcx> {
-    pub fn identity_unevaluated(
+    /// Creates an unevaluated const from a `DefId` for a const item.
+    /// The binders of the const item still need to be instantiated.
+    pub fn from_unevaluated(
         tcx: TyCtxt<'tcx>,
         def_id: DefId,
     ) -> ty::EarlyBinder<'tcx, Const<'tcx>> {
@@ -329,18 +331,6 @@ impl<'tcx> Const<'tcx> {
         }
     }
 
-    /// Normalizes the constant to a value or an error if possible.
-    #[inline]
-    pub fn normalize(self, tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>) -> Self {
-        match self.eval(tcx, param_env, DUMMY_SP) {
-            Ok(val) => Self::Val(val, self.ty()),
-            Err(ErrorHandled::Reported(guar, _span)) => {
-                Self::Ty(Ty::new_error(tcx, guar.into()), ty::Const::new_error(tcx, guar.into()))
-            }
-            Err(ErrorHandled::TooGeneric(_span)) => self,
-        }
-    }
-
     #[inline]
     pub fn try_eval_scalar(
         self,

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -699,23 +699,17 @@ impl<'tcx> Cx<'tcx> {
                             }
                         }
                         hir::InlineAsmOperand::Const { ref anon_const } => {
-                            let value = mir::Const::identity_unevaluated(
+                            let value =
-                                tcx,
+                                mir::Const::from_unevaluated(tcx, anon_const.def_id.to_def_id())
-                                anon_const.def_id.to_def_id(),
+                                    .instantiate_identity();
-                            )
-                            .instantiate_identity()
-                            .normalize(tcx, self.param_env);
                             let span = tcx.def_span(anon_const.def_id);
 
                             InlineAsmOperand::Const { value, span }
                         }
                         hir::InlineAsmOperand::SymFn { ref anon_const } => {
-                            let value = mir::Const::identity_unevaluated(
+                            let value =
-                                tcx,
+                                mir::Const::from_unevaluated(tcx, anon_const.def_id.to_def_id())
-                                anon_const.def_id.to_def_id(),
+                                    .instantiate_identity();
-                            )
-                            .instantiate_identity()
-                            .normalize(tcx, self.param_env);
                             let span = tcx.def_span(anon_const.def_id);
 
                             InlineAsmOperand::SymFn { value, span }

compiler/rustc_mir_transform/src/jump_threading.rs

@@ -516,9 +516,7 @@ impl<'a, 'tcx> TOFinder<'a, 'tcx> {
                     // Avoid handling them, though this could be extended in the future.
                     return;
                 }
-                let Some(value) =
+                let Some(value) = value.const_.try_eval_scalar_int(self.tcx, self.param_env) else {
-                    value.const_.normalize(self.tcx, self.param_env).try_to_scalar_int()
-                else {
                     return;
                 };
                 let conds = conditions.map(self.arena, |c| Condition {

tests/ui/asm/const-error.rs

@@ -1,14 +1,16 @@
 //@ only-x86_64
 //@ needs-asm-support
+//@ check-pass
 
-// Test to make sure that we emit const errors eagerly for inline asm
+// Test to make sure that we emit const errors late for inline asm,
+// which is consistent with inline const blocks.
 
 use std::arch::asm;
 
 fn test<T>() {
     unsafe {
+        // No error here, as this does not get monomorphized.
         asm!("/* {} */", const 1 / 0);
-        //~^ ERROR evaluation of
     }
 }
 

tests/ui/asm/const-error.stderr

@@ -1,9 +0,0 @@
-error[E0080]: evaluation of `test::<T>::{constant#0}` failed
-  --> $DIR/const-error.rs:10:32
-   |
-LL |         asm!("/* {} */", const 1 / 0);
-   |                                ^^^^^ attempt to divide `1_i32` by zero
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0080`.