From c6659251c92c13c958c1b086f804abf1ec8e247f Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?R=C3=A9my=20Rakic?= Date: Tue, 12 Nov 2024 11:21:43 +0000 Subject: [PATCH] clarify `must_produce_diag` ICE for debugging --- compiler/rustc_errors/src/lib.rs | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/compiler/rustc_errors/src/lib.rs b/compiler/rustc_errors/src/lib.rs index 94365a89adc..98200c367f9 100644 --- a/compiler/rustc_errors/src/lib.rs +++ b/compiler/rustc_errors/src/lib.rs @@ -623,12 +623,25 @@ impl Drop for DiagCtxtInner { self.flush_delayed() } + // Sanity check: did we use some of the expensive `trimmed_def_paths` functions + // unexpectedly, that is, without producing diagnostics? If so, for debugging purposes, we + // suggest where this happened and how to avoid it. if !self.has_printed && !self.suppressed_expected_diag && !std::thread::panicking() { if let Some(backtrace) = &self.must_produce_diag { + let suggestion = match backtrace.status() { + BacktraceStatus::Disabled => String::from( + "Backtraces are currently disabled: set `RUST_BACKTRACE=1` and re-run \ + to see where it happened.", + ), + BacktraceStatus::Captured => format!( + "This happened in the following `must_produce_diag` call's backtrace:\n\ + {backtrace}", + ), + _ => String::from("(impossible to capture backtrace where this happened)"), + }; panic!( - "must_produce_diag: `trimmed_def_paths` called but no diagnostics emitted; \ - `with_no_trimmed_paths` for debugging. \ - called at: {backtrace}" + "`trimmed_def_paths` called, diagnostics were expected but none were emitted. \ + Use `with_no_trimmed_paths` for debugging. {suggestion}" ); } }