bjoernager/rust
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Add -Z dont-buffer-diagnostics, a way to force NLL to immediately emit its diagnostics.

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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.
This commit is contained in:
Felix S. Klock II 2018-09-15 06:27:55 +02:00
parent f789b6bd6d
commit 82e1750414
4 changed files with 27 additions and 2 deletions
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14
src/librustc_errors/diagnostic_builder.rs
View file

@ -21,6 +21,10 @@ use std::thread::panicking;
use syntax_pos::{MultiSpan, Span};
/// Used for emitting structured error messages and other diagnostic information.
///
/// If there is some state in a downstream crate you would like to
/// access in the methods of `DiagnosticBuilder` here, consider
/// extending `HandlerFlags`, accessed via `self.handler.flags`.
#[must_use]
#[derive(Clone)]
pub struct DiagnosticBuilder<'a> {
@ -89,8 +93,14 @@ impl<'a> DiagnosticBuilder<'a> {
self.cancel();
}
/// Buffers the diagnostic for later emission.
pub fn buffer(self, buffered_diagnostics: &mut Vec<Diagnostic>) {
/// Buffers the diagnostic for later emission, unless handler
/// has disabled such buffering.
pub fn buffer(mut self, buffered_diagnostics: &mut Vec<Diagnostic>) {
if self.handler.flags.dont_buffer_diagnostics || self.handler.flags.treat_err_as_bug {
self.emit();
return;
}
// We need to use `ptr::read` because `DiagnosticBuilder`
// implements `Drop`.
let diagnostic;

11
src/librustc_errors/lib.rs
View file

@ -303,9 +303,20 @@ thread_local!(pub static TRACK_DIAGNOSTICS: Cell<fn(&Diagnostic)> =
#[derive(Default)]
pub struct HandlerFlags {
/// If false, warning-level lints are suppressed.
/// (rustc: see `--allow warnings` and `--cap-lints`)
pub can_emit_warnings: bool,
/// If true, error-level diagnostics are upgraded to bug-level.
/// (rustc: see `-Z treat-err-as-bug`)
pub treat_err_as_bug: bool,
/// If true, immediately emit diagnostics that would otherwise be buffered.
/// (rustc: see `-Z dont-buffer-diagnostics` and `-Z treat-err-as-bug`)
pub dont_buffer_diagnostics: bool,
/// If true, immediately print bugs registered with `delay_span_bug`.
/// (rustc: see `-Z report-delayed-bugs`)
pub report_delayed_bugs: bool,
/// show macro backtraces even for non-local macros.
/// (rustc: see `-Z external-macro-backtrace`)
pub external_macro_backtrace: bool,
}