Add -Z dont-buffer-diagnostics, a way to force NLL to immediately emit its diagnostics.
This is mainly intended for `rustc` developers who want to see a
diagnostic in its original context in the control flow. Two uses
cases for that are:
* `-Z treat-err-as-bug` which then allows extraction of a stack-trace to the origin of the error
(a case that is so important that we make that flag imply this one, effectively).
* `RUST_LOG=... rustc`, in which case it is often useful to see the logging statements that
occurred immediately prior to the point where the diagnostic was signalled.
Drive-by: Added some documentation pointing future devs at
HandlerFlags, and documented the fields of `HandlerFlags` itself.
diff --git a/src/librustc/session/config.rs b/src/librustc/session/config.rs
index 2a9732b..2569812 100644
--- a/src/librustc/session/config.rs
+++ b/src/librustc/session/config.rs
@@ -1331,6 +1331,8 @@
"disable user provided type assertion in NLL"),
nll_dont_emit_read_for_match: bool = (false, parse_bool, [UNTRACKED],
"in match codegen, do not include ReadForMatch statements (used by mir-borrowck)"),
+ dont_buffer_diagnostics: bool = (false, parse_bool, [UNTRACKED],
+ "emit diagnostics rather than buffering (breaks NLL error downgrading, sorting)."),
polonius: bool = (false, parse_bool, [UNTRACKED],
"enable polonius-based borrow-checker"),
codegen_time_graph: bool = (false, parse_bool, [UNTRACKED],
