Only enable ConstProp at mir-opt-level >= 2.

Author: cjgillot

compiler/rustc_mir_transform/src/const_prop.rs

@@ -54,7 +54,7 @@ pub struct ConstProp;
 
 impl<'tcx> MirPass<'tcx> for ConstProp {
     fn is_enabled(&self, sess: &rustc_session::Session) -> bool {
-        sess.mir_opt_level() >= 1
+        sess.mir_opt_level() >= 2
     }
 
     #[instrument(skip(self, tcx), level = "debug")]

tests/ui/associated-consts/defaults-not-assumed-fail.stderr

@@ -26,14 +26,6 @@ LL |     assert_eq!(<() as Tr>::B, 0);    // causes the error above
    |
    = note: this note originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-note: erroneous constant used
-  --> $DIR/defaults-not-assumed-fail.rs:33:5
-   |
-LL |     assert_eq!(<() as Tr>::B, 0);    // causes the error above
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this note originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
-
 error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0080`.

tests/ui/consts/const-err-late.stderr

@@ -28,12 +28,6 @@ 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: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0080`.

tests/ui/consts/const-eval/issue-44578.stderr

@@ -26,14 +26,6 @@ LL |     println!("{}", <Bar<u16, u8> as Foo>::AMT);
    |
    = note: this note originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-note: erroneous constant used
-  --> $DIR/issue-44578.rs:25:20
-   |
-LL |     println!("{}", <Bar<u16, u8> as Foo>::AMT);
-   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this note originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
-
 error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0080`.

tests/ui/consts/miri_unleashed/assoc_const.stderr

@@ -25,12 +25,6 @@ note: erroneous constant used
 LL |     let y = <String as Bar<Vec<u32>, String>>::F;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-note: erroneous constant used
-  --> $DIR/assoc_const.rs:29:13
-   |
-LL |     let y = <String as Bar<Vec<u32>, String>>::F;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-
 warning: skipping const checks
    |
 help: skipping check that does not even have a feature gate

tests/ui/consts/miri_unleashed/assoc_const_2.stderr

@@ -16,12 +16,6 @@ note: erroneous constant used
 LL |     let y = <String as Bar<String>>::F;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-note: erroneous constant used
-  --> $DIR/assoc_const_2.rs:27:13
-   |
-LL |     let y = <String as Bar<String>>::F;
-   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^
-
 error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0080`.

tests/ui/consts/uninhabited-const-issue-61744.stderr

@@ -657,12 +657,6 @@ note: erroneous constant used
 LL |     dbg!(i32::CONSTANT);
    |          ^^^^^^^^^^^^^
 
-note: erroneous constant used
-  --> $DIR/uninhabited-const-issue-61744.rs:18:10
-   |
-LL |     dbg!(i32::CONSTANT);
-   |          ^^^^^^^^^^^^^
-
 error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0080`.

tests/ui/limits/issue-55878.stderr

@@ -25,14 +25,6 @@ LL |     println!("Size: {}", std::mem::size_of::<[u8; u64::MAX as usize]>());
    |
    = note: this note originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-note: erroneous constant used
-  --> $DIR/issue-55878.rs:7:26
-   |
-LL |     println!("Size: {}", std::mem::size_of::<[u8; u64::MAX as usize]>());
-   |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: this note originates in the macro `$crate::format_args_nl` which comes from the expansion of the macro `println` (in Nightly builds, run with -Z macro-backtrace for more info)
-
 error: aborting due to previous error
 
 For more information about this error, try `rustc --explain E0080`.