fix show we're just showing... message instead of the end of query st…

…ack message when RUST_BACKTRACE=0

compiler/rustc_middle/src/ty/query/plumbing.rs

@@ -170,7 +170,11 @@ impl<'tcx> TyCtxt<'tcx> {
             }
         });
 
-        eprintln!("end of query stack");
+        if num_frames != None {
+            eprintln!("we're just showing a limited slice of the query stack");
+        } else {
+            eprintln!("end of query stack");
+        }
     }
 }
 

src/test/ui/pattern/const-pat-ice.stderr

@@ -0,0 +1,17 @@
+thread 'rustc' panicked at 'assertion failed: rows.iter().all(|r| r.len() == v.len())', compiler/rustc_mir_build/src/thir/pattern/_match.rs:LL:CC
+note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
+
+error: internal compiler error: unexpected panic
+
+note: the compiler unexpectedly panicked. this is a bug.
+
+note: we would appreciate a bug report: https://github.com/rust-lang/rust/issues/new?labels=C-bug%2C+I-ICE%2C+T-compiler&template=ice.md
+
+note: rustc VERSION running on TARGET
+
+note: compiler flags: FLAGS
+
+query stack during panic:
+#0 [check_match] match-checking `main`
+#1 [analysis] running analysis passes on this crate
+we're just showing a limited slice of the query stack