Remove panic: prefix in label from builtin macros

Author: estebank

compiler/rustc_const_eval/src/const_eval/error.rs

@@ -34,7 +34,17 @@ impl MachineStopType for ConstEvalErrKind {
         match self {
             ConstAccessesMutGlobal => const_eval_const_accesses_mut_global,
             ModifiedGlobal => const_eval_modified_global,
-            Panic { .. } => const_eval_panic,
+            Panic { msg, .. } => {
+                let msg = msg.as_str();
+                match msg {
+                    "explicit panic"
+                    | "not implemented"
+                    | "not yet implemented"
+                    | "internal error: entered unreachable code" => msg.to_string().into(),
+                    _ if msg.starts_with("assertion failed: ") => msg.to_string().into(),
+                    _ => const_eval_panic,
+                }
+            }
             RecursiveStatic => const_eval_recursive_static,
             AssertFailure(x) => x.diagnostic_message(),
             WriteThroughImmutablePointer => const_eval_write_through_immutable_pointer,

src/tools/miri/tests/fail/erroneous_const.stderr

@@ -2,7 +2,7 @@ error[E0080]: evaluation of `PrintName::<i32>::VOID` failed
   --> tests/fail/erroneous_const.rs:LL:CC
    |
 LL |     const VOID: ! = panic!();
-   |                     ^^^^^^^^ panic: explicit panic
+   |                     ^^^^^^^^ explicit panic
    |
    = note: this error originates in the macro `$crate::panic::panic_2021` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)