Auto merge of #75145 - davidtwco:issue-60607-preallocate-defid-for-lang-items, r=petrochenkov

Reference lang items during AST lowering

Fixes #60607 and fixes #61019.

This PR introduces `QPath::LangItem` to the HIR and uses it in AST lowering instead of constructing a `hir::Path` from a slice of symbols:

- Credit for much of this work goes to @matthewjasper, I basically just [rebased their earlier work](a227c706b7 (diff-c0f791ead38d2d02916faaad0f56f41d)).
- ~~Changes to Clippy might not be correct, they compile but attempting to run tests through `./x.py` produced failures which appeared spurious, so I didn't run any clippy tests.~~
- Changes to save analysis might not be correct - tests pass but I don't have a lot of confidence in those changes being correct.
- I've used `GenericBounds::LangItemTrait` rather than changing `PolyTraitRef`, as suggested by @matthewjasper [in this comment](a227c706b7 (r40107992)) but I'd prefer that be left for a follow-up.
- I've split things into smaller commits fairly arbitrarily to make the diff easier to review, each commit should compile but might not pass tests until the final commit.

r? @oli-obk
cc @matthewjasper

src/test/ui/hygiene/hir-res-hygiene.rs

@@ -0,0 +1,18 @@
+// check-pass
+// edition:2018
+// aux-build:not-libstd.rs
+
+// Check that paths created in HIR are not affected by in scope names.
+
+extern crate not_libstd as std;
+
+async fn the_future() {
+    async {}.await;
+}
+
+fn main() -> Result<(), ()> {
+    for i in 0..10 {}
+    for j in 0..=10 {}
+    Ok(())?;
+    Ok(())
+}

src/test/ui/range/range-1.stderr

@@ -17,9 +17,13 @@ error[E0277]: the size for values of type `[{integer}]` cannot be known at compi
    |
 LL |     let range = *arr..;
    |                 ^^^^^^ doesn't have a size known at compile-time
+   | 
+  ::: $SRC_DIR/core/src/ops/range.rs:LL:COL
+   |
+LL | pub struct RangeFrom<Idx> {
+   |                      --- required by this bound in `std::ops::RangeFrom`
    |
    = help: the trait `std::marker::Sized` is not implemented for `[{integer}]`
-   = note: required by `std::ops::RangeFrom`
 
 error: aborting due to 3 previous errors