Auto merge of #108872 - cjgillot:simp-const-prop, r=oli-obk

Strengthen state tracking in const-prop

Some/many of the changes are replicated between both the const-prop lint and the const-prop optimization.

Behaviour changes:
- const-prop opt does not give a span to propagated values. This was useless as that span's primary purpose is to diagnose evaluation failure in codegen.
- we remove the `OnlyPropagateInto` mode. It was only used for function arguments, which are better modeled by a write before entry.
- the tracking of assignments and discriminants make clearer that we do nothing in `NoPropagation` mode or on indirect places.

1 files changed, 6 insertions, 6 deletions

diff --git a/tests/ui/consts/const-err-late.stderr b/tests/ui/consts/const-err-late.stderr
index cb0cab2444b..192b9ba204b 100644
--- a/tests/ui/consts/const-err-late.stderr
+++ b/tests/ui/consts/const-err-late.stderr
@@ -10,12 +10,6 @@ note: erroneous constant used
 LL |     black_box((S::<i32>::FOO, S::<u32>::FOO));
    |                ^^^^^^^^^^^^^
 
-note: erroneous constant used
-  --> $DIR/const-err-late.rs:19:16
-   |
-LL |     black_box((S::<i32>::FOO, S::<u32>::FOO));
-   |                ^^^^^^^^^^^^^
-
 error[E0080]: evaluation of `S::<u32>::FOO` failed
   --> $DIR/const-err-late.rs:13:21
    |
@@ -34,6 +28,12 @@ note: erroneous constant used
 LL |     black_box((S::<i32>::FOO, S::<u32>::FOO));
    |                ^^^^^^^^^^^^^
 
+note: erroneous constant used
+  --> $DIR/const-err-late.rs:19:16
+   |
+LL |     black_box((S::<i32>::FOO, S::<u32>::FOO));
+   |                ^^^^^^^^^^^^^
+
 error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0080`.