Erase regions in new abstract consts

compiler/rustc_trait_selection/src/traits/const_evaluatable.rs

@@ -236,7 +236,7 @@ impl<'tcx> AbstractConst<'tcx> {
     ) -> Result<Option<AbstractConst<'tcx>>, ErrorGuaranteed> {
         let inner = tcx.thir_abstract_const_opt_const_arg(uv.def)?;
         debug!("AbstractConst::new({:?}) = {:?}", uv, inner);
-        Ok(inner.map(|inner| AbstractConst { inner, substs: uv.substs }))
+        Ok(inner.map(|inner| AbstractConst { inner, substs: tcx.erase_regions(uv.substs) }))
     }
 
     pub fn from_const(
@@ -416,6 +416,7 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
                     // `AbstractConst`s should not contain any promoteds as they require references which
                     // are not allowed.
                     assert_eq!(ct.promoted, None);
+                    assert_eq!(ct, self.tcx.erase_regions(ct));
                 }
             }
         }

src/test/ui/const-generics/try_unify_ignore_lifetimes.rs

@@ -0,0 +1,33 @@
+// check-pass
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+struct Num<const N: usize>;
+
+trait NumT {
+    const VALUE: usize;
+}
+
+impl<const N: usize> NumT for Num<N> {
+    const VALUE: usize = N;
+}
+
+struct Foo<'a, N: NumT>(&'a [u32; N::VALUE]) where [(); N::VALUE]:;
+
+trait Bar {
+    type Size: NumT;
+
+    fn bar<'a>(foo: &Foo<'a, Self::Size>) where [(); Self::Size::VALUE]: {
+        todo!();
+    }
+}
+
+trait Baz<'a> {
+    type Size: NumT;
+
+    fn baz(foo: &Foo<'a, Self::Size>) where [(); Self::Size::VALUE]: {
+        todo!();
+    }
+}
+
+fn main() {}