From 23fd2860fa0aa521083019df952d762b43400212 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Wed, 20 Sep 2023 22:28:46 +0200
Subject: [PATCH] stronger consistency check in ImmTy::from_immediate

---
 compiler/rustc_const_eval/src/interpret/operand.rs | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index c351fa84d37..62efa84f869 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -159,7 +159,15 @@ pub fn from_scalar(val: Scalar<Prov>, layout: TyAndLayout<'tcx>) -> Self {
 
     #[inline(always)]
     pub fn from_immediate(imm: Immediate<Prov>, layout: TyAndLayout<'tcx>) -> Self {
-        debug_assert!(layout.is_sized(), "immediates must be sized");
+        debug_assert!(
+            match (imm, layout.abi) {
+                (Immediate::Scalar(..), Abi::Scalar(..)) => true,
+                (Immediate::ScalarPair(..), Abi::ScalarPair(..)) => true,
+                (Immediate::Uninit, _) if layout.is_sized() => true,
+                _ => false,
+            },
+            "immediate {imm:?} does not fit to layout {layout:?}",
+        );
         ImmTy { imm, layout }
     }
 
@@ -448,7 +456,7 @@ fn read_immediate_from_mplace_raw(
                     alloc_range(Size::ZERO, size),
                     /*read_provenance*/ matches!(s, abi::Pointer(_)),
                 )?;
-                Some(ImmTy { imm: scalar.into(), layout: mplace.layout })
+                Some(ImmTy::from_scalar(scalar, mplace.layout))
             }
             Abi::ScalarPair(
                 abi::Scalar::Initialized { value: a, .. },
@@ -468,7 +476,7 @@ fn read_immediate_from_mplace_raw(
                     alloc_range(b_offset, b_size),
                     /*read_provenance*/ matches!(b, abi::Pointer(_)),
                 )?;
-                Some(ImmTy { imm: Immediate::ScalarPair(a_val, b_val), layout: mplace.layout })
+                Some(ImmTy::from_immediate(Immediate::ScalarPair(a_val, b_val), mplace.layout))
             }
             _ => {
                 // Neither a scalar nor scalar pair.