Enable ConstPropLint for promoteds

This fixes the issue wherein the lint didn't fire for promoteds
in the case of SHL/SHR operators in non-optimized builds
and all arithmetic operators in optimized builds

Author: gurry

compiler/rustc_mir_transform/src/const_prop_lint.rs

@@ -32,11 +32,6 @@ impl<'tcx> MirLint<'tcx> for ConstPropLint {
             return;
         }
 
-        // will be evaluated by miri and produce its errors there
-        if body.source.promoted.is_some() {
-            return;
-        }
-
         let def_id = body.source.def_id().expect_local();
         let def_kind = tcx.def_kind(def_id);
         let is_fn_like = def_kind.is_fn_like();

src/tools/miri/tests/pass/overflow_checks_off.rs

@@ -1,12 +1,17 @@
 //@compile-flags: -C overflow-checks=off
 
 // Check that we correctly implement the intended behavior of these operators
-// when they are not being overflow-checked.
+// when they are not being overflow-checked at runtime.
 
 // FIXME: if we call the functions in `std::ops`, we still get the panics.
 // Miri does not implement the codegen-time hack that backs `#[rustc_inherit_overflow_checks]`.
 // use std::ops::*;
 
+
+// Disable _compile-time_ overflow linting
+// so that we can test runtime overflow checks
+ #![allow(arithmetic_overflow)]
+
 fn main() {
     assert_eq!(-{ -0x80i8 }, -0x80);
 

tests/ui/associated-consts/defaults-cyclic-fail.stderr

@@ -20,7 +20,7 @@ note: ...which requires const-evaluating + checking `Tr::B`...
 LL |     const B: u8 = Self::A;
    |                   ^^^^^^^
    = note: ...which again requires simplifying constant for the type system `Tr::A`, completing the cycle
-note: cycle used when const-evaluating + checking `main::promoted[1]`
+note: cycle used when optimizing promoted MIR for `main`
   --> $DIR/defaults-cyclic-fail.rs:16:16
    |
 LL |     assert_eq!(<() as Tr>::A, 0);

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

@@ -10,6 +10,14 @@ note: erroneous constant encountered
 LL |     assert_eq!(<() as Tr>::B, 0);    // causes the error above
    |                ^^^^^^^^^^^^^
 
+note: erroneous constant encountered
+  --> $DIR/defaults-not-assumed-fail.rs:33:16
+   |
+LL |     assert_eq!(<() as Tr>::B, 0);    // causes the error above
+   |                ^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 note: erroneous constant encountered
   --> $DIR/defaults-not-assumed-fail.rs:33:5
    |

tests/ui/consts/const-err2.noopt.stderr

@@ -10,6 +10,14 @@ note: erroneous constant encountered
 LL |     println!("{}", <Bar<u16, u8> as Foo>::AMT);
    |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
 
+note: erroneous constant encountered
+  --> $DIR/issue-44578.rs:25:20
+   |
+LL |     println!("{}", <Bar<u16, u8> as Foo>::AMT);
+   |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
 note: erroneous constant encountered
   --> $DIR/issue-44578.rs:25:20
    |

tests/ui/consts/const-err2.opt.stderr

@@ -14,6 +14,7 @@ struct Sum<A, B>(A, B);
 impl<A: Unsigned, B: Unsigned> Unsigned for Sum<A, B> {
     const MAX: u8 = A::MAX + B::MAX;
     //~^ ERROR evaluation of `<Sum<U8, U8> as Unsigned>::MAX` failed
+    //~| ERROR evaluation of `<Sum<U8, U8> as Unsigned>::MAX` failed
 }
 
 fn foo<T>(_: T) -> &'static u8 {