From d5e79f2b8d84fa64eed0da6413874560b2552900 Mon Sep 17 00:00:00 2001
From: Martin Nordholts <enselic@gmail.com>
Date: Thu, 24 Aug 2023 06:43:52 +0200
Subject: [PATCH] Include compiler flags when you `break rust;`

---
 compiler/rustc_hir_typeck/src/lib.rs    | 6 ++++++
 tests/ui/track-diagnostics/track.rs     | 5 +++++
 tests/ui/track-diagnostics/track.stderr | 2 ++
 3 files changed, 13 insertions(+)

diff --git a/compiler/rustc_hir_typeck/src/lib.rs b/compiler/rustc_hir_typeck/src/lib.rs
index c4d3cbc9faa..f17f1d14bf3 100644
--- a/compiler/rustc_hir_typeck/src/lib.rs
+++ b/compiler/rustc_hir_typeck/src/lib.rs
@@ -436,6 +436,12 @@ fn fatally_break_rust(tcx: TyCtxt<'_>) {
         tcx.sess.cfg_version,
         config::host_triple(),
     ));
+    if let Some((flags, excluded_cargo_defaults)) = rustc_session::utils::extra_compiler_flags() {
+        handler.note_without_error(format!("compiler flags: {}", flags.join(" ")));
+        if excluded_cargo_defaults {
+            handler.note_without_error("some of the compiler flags provided by cargo are hidden");
+        }
+    }
 }
 
 fn has_expected_num_generic_args(tcx: TyCtxt<'_>, trait_did: DefId, expected: usize) -> bool {
diff --git a/tests/ui/track-diagnostics/track.rs b/tests/ui/track-diagnostics/track.rs
index 61b9137eadd..97bd7789a63 100644
--- a/tests/ui/track-diagnostics/track.rs
+++ b/tests/ui/track-diagnostics/track.rs
@@ -6,6 +6,11 @@
 // normalize-stderr-test ".rs:\d+:\d+" -> ".rs:LL:CC"
 // normalize-stderr-test "note: rustc .+ running on .+" -> "note: rustc $$VERSION running on $$TARGET"
 
+// The test becomes too flaky if we care about exact args. If `-Z ui-testing`
+// from compiletest and `-Z track-diagnostics` from `// compile-flags` at the
+// top of this file are present, then assume all args are present.
+// normalize-stderr-test "note: compiler flags: .*-Z ui-testing.*-Z track-diagnostics" -> "note: compiler flags: ... -Z ui-testing ... -Z track-diagnostics"
+
 fn main() {
     break rust
 }
diff --git a/tests/ui/track-diagnostics/track.stderr b/tests/ui/track-diagnostics/track.stderr
index 8256c1f5f0f..60254dc475b 100644
--- a/tests/ui/track-diagnostics/track.stderr
+++ b/tests/ui/track-diagnostics/track.stderr
@@ -20,6 +20,8 @@ note: we would appreciate a joke overview: https://github.com/rust-lang/rust/iss
 
 note: rustc $VERSION running on $TARGET
 
+note: compiler flags: ... -Z ui-testing ... -Z track-diagnostics
+
 error: aborting due to 3 previous errors
 
 Some errors have detailed explanations: E0268, E0425.