Erase regions in New Abstract Consts

[JulianKnodt]

When an abstract const is constructed, we previously included lifetimes in the set of substitutes, so it was not able to unify two abstract consts if their lifetimes did not match but the values did, despite the values not depending on the lifetimes. This caused code that should have compiled to not compile.

Fixes#98452

r? @lcnr

[rust-highfive]

Some changes occured in const_evaluatable.rs

cc @lcnr

[lcnr]

can you add an assert here

rust/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs

Lines 413 to 421 in 64eb9ab

	for n inself.nodes.iter(){
	ifletNode::Leaf(ct) = n {
	iflet ty::ConstKind::Unevaluated(ct) = ct.kind(){
	// `AbstractConst`s should not contain any promoteds as they require references which
	// are not allowed.
	assert_eq!(ct.promoted,None);
	}
	}
	}

that all regions from inside the abstract const are also erased, so something like assert_eq!(ct, self.tcx.erase_regions(ct));

then r=me

[rustbot]

Some changes occurred in const_evaluatable.rs

cc @lcnr

[lcnr]

@bors r+ rollup

[bors]

📌 Commit 1e40200 has been approved by lcnr