Rollup merge of #86478 - ehuss:future-incompat-test, r=oli-obk

Add -Zfuture-incompat-test to assist with testing future-incompat reports.

This adds a `-Zfuture-incompat-test` cli flag to assist with testing future-incompatible reports. This flag causes all lints to be treated as a future-incompatible lint, and will emit a report for them. This is being added so that Cargo's testsuite can reliably test the reporting infrastructure.  Right now, Cargo relies on using array_into_iter as a test subject. Since the breaking "future incompatible" lints are never intended to last forever, this means Cargo's testsuite would always need to keep changing to choose different lints (for example, #86330 proposed dropping that moniker for array_into_iter). With this flag, Cargo's tests can trigger any lint and check for the report.

1 files changed, 1 insertions, 0 deletions

diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index a053253ec16..5a362a37f2b 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -633,6 +633,7 @@ fn test_debugging_options_tracking_hash() {
     untracked!(dump_mir_graphviz, true);
     untracked!(emit_future_incompat_report, true);
     untracked!(emit_stack_sizes, true);
+    untracked!(future_incompat_test, true);
     untracked!(hir_stats, true);
     untracked!(identify_regions, true);
     untracked!(incremental_ignore_spans, true);