Rollup merge of #64374 - nnethercote:box-DiagnosticBuilder, r=zackmdavis
Box `DiagnosticBuilder`. It's a large type -- 176 bytes on 64-bit. And it's passed around and returned from a lot of functions, including within `PResult`. This commit boxes it, which reduces memory traffic. In particular, `PResult` shrinks to 16 bytes in the best case; this reduces instruction counts by up to 2% on various workloads. The commit touches a lot of lines but it's almost all trivial plumbing changes.
This commit is contained in:
commit
af33a1d902
4 changed files with 55 additions and 37 deletions
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@ -37,7 +37,7 @@ impl Emitter for AnnotateSnippetEmitterWriter {
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&mut primary_span,
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&mut children,
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&db.level,
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db.handler.flags.external_macro_backtrace);
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db.handler().flags.external_macro_backtrace);
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self.emit_messages_default(&db.level,
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db.message(),
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@ -18,8 +18,17 @@ use log::debug;
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/// extending `HandlerFlags`, accessed via `self.handler.flags`.
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#[must_use]
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#[derive(Clone)]
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pub struct DiagnosticBuilder<'a> {
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pub handler: &'a Handler,
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pub struct DiagnosticBuilder<'a>(Box<DiagnosticBuilderInner<'a>>);
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/// This is a large type, and often used as a return value, especially within
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/// the frequently-used `PResult` type. In theory, return value optimization
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/// (RVO) should avoid unnecessary copying. In practice, it does not (at the
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/// time of writing). The split between `DiagnosticBuilder` and
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/// `DiagnosticBuilderInner` exists to avoid many `memcpy` calls.
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#[must_use]
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#[derive(Clone)]
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struct DiagnosticBuilderInner<'a> {
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handler: &'a Handler,
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diagnostic: Diagnostic,
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allow_suggestions: bool,
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}
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@ -52,7 +61,7 @@ macro_rules! forward {
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) => {
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$(#[$attrs])*
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pub fn $n(&mut self, $($name: $ty),*) -> &mut Self {
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self.diagnostic.$n($($name),*);
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self.0.diagnostic.$n($($name),*);
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self
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}
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};
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@ -69,7 +78,7 @@ macro_rules! forward {
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) => {
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$(#[$attrs])*
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pub fn $n<S: Into<MultiSpan>>(&mut self, $($name: $ty),*) -> &mut Self {
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self.diagnostic.$n($($name),*);
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self.0.diagnostic.$n($($name),*);
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self
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}
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};
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@ -79,24 +88,28 @@ impl<'a> Deref for DiagnosticBuilder<'a> {
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type Target = Diagnostic;
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fn deref(&self) -> &Diagnostic {
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&self.diagnostic
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&self.0.diagnostic
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}
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}
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impl<'a> DerefMut for DiagnosticBuilder<'a> {
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fn deref_mut(&mut self) -> &mut Diagnostic {
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&mut self.diagnostic
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&mut self.0.diagnostic
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}
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}
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impl<'a> DiagnosticBuilder<'a> {
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pub fn handler(&self) -> &'a Handler{
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self.0.handler
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}
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/// Emit the diagnostic.
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pub fn emit(&mut self) {
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if self.cancelled() {
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return;
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}
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self.handler.emit_db(&self);
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self.0.handler.emit_db(&self);
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self.cancel();
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}
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@ -115,8 +128,8 @@ impl<'a> DiagnosticBuilder<'a> {
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/// Buffers the diagnostic for later emission, unless handler
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/// has disabled such buffering.
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pub fn buffer(mut self, buffered_diagnostics: &mut Vec<Diagnostic>) {
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if self.handler.flags.dont_buffer_diagnostics ||
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self.handler.flags.treat_err_as_bug.is_some()
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if self.0.handler.flags.dont_buffer_diagnostics ||
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self.0.handler.flags.treat_err_as_bug.is_some()
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{
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self.emit();
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return;
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@ -126,7 +139,7 @@ impl<'a> DiagnosticBuilder<'a> {
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// implements `Drop`.
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let diagnostic;
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unsafe {
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diagnostic = std::ptr::read(&self.diagnostic);
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diagnostic = std::ptr::read(&self.0.diagnostic);
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std::mem::forget(self);
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};
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// Logging here is useful to help track down where in logs an error was
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@ -144,7 +157,7 @@ impl<'a> DiagnosticBuilder<'a> {
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span: Option<S>,
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) -> &mut Self {
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let span = span.map(|s| s.into()).unwrap_or_else(|| MultiSpan::new());
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self.diagnostic.sub(level, message, span, None);
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self.0.diagnostic.sub(level, message, span, None);
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self
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}
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@ -160,7 +173,7 @@ impl<'a> DiagnosticBuilder<'a> {
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/// locally in whichever way makes the most sense.
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pub fn delay_as_bug(&mut self) {
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self.level = Level::Bug;
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self.handler.delay_as_bug(self.diagnostic.clone());
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self.0.handler.delay_as_bug(self.0.diagnostic.clone());
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self.cancel();
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}
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@ -171,7 +184,7 @@ impl<'a> DiagnosticBuilder<'a> {
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/// then the snippet will just include that `Span`, which is
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/// called the primary span.
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pub fn span_label<T: Into<String>>(&mut self, span: Span, label: T) -> &mut Self {
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self.diagnostic.span_label(span, label);
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self.0.diagnostic.span_label(span, label);
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self
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}
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@ -208,10 +221,10 @@ impl<'a> DiagnosticBuilder<'a> {
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suggestion: Vec<(Span, String)>,
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applicability: Applicability,
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) -> &mut Self {
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if !self.allow_suggestions {
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if !self.0.allow_suggestions {
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return self
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}
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self.diagnostic.multipart_suggestion(
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self.0.diagnostic.multipart_suggestion(
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msg,
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suggestion,
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applicability,
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@ -225,10 +238,10 @@ impl<'a> DiagnosticBuilder<'a> {
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suggestion: Vec<(Span, String)>,
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applicability: Applicability,
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) -> &mut Self {
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if !self.allow_suggestions {
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if !self.0.allow_suggestions {
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return self
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}
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self.diagnostic.tool_only_multipart_suggestion(
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self.0.diagnostic.tool_only_multipart_suggestion(
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msg,
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suggestion,
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applicability,
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@ -236,7 +249,6 @@ impl<'a> DiagnosticBuilder<'a> {
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self
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}
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pub fn span_suggestion(
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&mut self,
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sp: Span,
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@ -244,10 +256,10 @@ impl<'a> DiagnosticBuilder<'a> {
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suggestion: String,
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applicability: Applicability,
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) -> &mut Self {
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if !self.allow_suggestions {
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if !self.0.allow_suggestions {
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return self
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}
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self.diagnostic.span_suggestion(
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self.0.diagnostic.span_suggestion(
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sp,
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msg,
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suggestion,
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@ -263,10 +275,10 @@ impl<'a> DiagnosticBuilder<'a> {
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suggestions: impl Iterator<Item = String>,
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applicability: Applicability,
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) -> &mut Self {
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if !self.allow_suggestions {
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if !self.0.allow_suggestions {
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return self
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}
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self.diagnostic.span_suggestions(
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self.0.diagnostic.span_suggestions(
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sp,
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msg,
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suggestions,
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@ -282,10 +294,10 @@ impl<'a> DiagnosticBuilder<'a> {
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suggestion: String,
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applicability: Applicability,
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) -> &mut Self {
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if !self.allow_suggestions {
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if !self.0.allow_suggestions {
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return self
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}
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self.diagnostic.span_suggestion_short(
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self.0.diagnostic.span_suggestion_short(
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sp,
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msg,
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suggestion,
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@ -301,10 +313,10 @@ impl<'a> DiagnosticBuilder<'a> {
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suggestion: String,
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applicability: Applicability,
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) -> &mut Self {
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if !self.allow_suggestions {
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if !self.0.allow_suggestions {
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return self
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}
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self.diagnostic.span_suggestion_hidden(
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self.0.diagnostic.span_suggestion_hidden(
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sp,
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msg,
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suggestion,
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@ -320,10 +332,10 @@ impl<'a> DiagnosticBuilder<'a> {
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suggestion: String,
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applicability: Applicability,
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) -> &mut Self {
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if !self.allow_suggestions {
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if !self.0.allow_suggestions {
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return self
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}
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self.diagnostic.tool_only_span_suggestion(
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self.0.diagnostic.tool_only_span_suggestion(
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sp,
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msg,
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suggestion,
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@ -336,7 +348,7 @@ impl<'a> DiagnosticBuilder<'a> {
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forward!(pub fn code(&mut self, s: DiagnosticId) -> &mut Self);
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pub fn allow_suggestions(&mut self, allow: bool) -> &mut Self {
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self.allow_suggestions = allow;
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self.0.allow_suggestions = allow;
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self
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}
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@ -359,19 +371,18 @@ impl<'a> DiagnosticBuilder<'a> {
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/// Creates a new `DiagnosticBuilder` with an already constructed
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/// diagnostic.
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pub fn new_diagnostic(handler: &'a Handler, diagnostic: Diagnostic)
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-> DiagnosticBuilder<'a> {
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DiagnosticBuilder {
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pub fn new_diagnostic(handler: &'a Handler, diagnostic: Diagnostic) -> DiagnosticBuilder<'a> {
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DiagnosticBuilder(Box::new(DiagnosticBuilderInner {
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handler,
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diagnostic,
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allow_suggestions: true,
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}
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}))
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}
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}
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impl<'a> Debug for DiagnosticBuilder<'a> {
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fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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self.diagnostic.fmt(f)
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self.0.diagnostic.fmt(f)
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}
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}
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@ -381,7 +392,7 @@ impl<'a> Drop for DiagnosticBuilder<'a> {
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fn drop(&mut self) {
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if !panicking() && !self.cancelled() {
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let mut db = DiagnosticBuilder::new(
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self.handler,
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self.0.handler,
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Level::Bug,
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"the following error was constructed but not emitted",
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);
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@ -385,7 +385,7 @@ impl Emitter for EmitterWriter {
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&mut primary_span,
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&mut children,
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&db.level,
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db.handler.flags.external_macro_backtrace);
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db.handler().flags.external_macro_backtrace);
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self.emit_messages_default(&db.level,
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&db.styled_message(),
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@ -13,6 +13,8 @@ use crate::symbol::Symbol;
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use errors::{Applicability, FatalError, Level, Handler, ColorConfig, Diagnostic, DiagnosticBuilder};
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use rustc_data_structures::fx::{FxHashSet, FxHashMap};
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#[cfg(target_arch = "x86_64")]
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use rustc_data_structures::static_assert_size;
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use rustc_data_structures::sync::{Lrc, Lock, Once};
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use syntax_pos::{Span, SourceFile, FileName, MultiSpan};
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use syntax_pos::edition::Edition;
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@ -38,6 +40,11 @@ crate mod unescape_error_reporting;
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pub type PResult<'a, T> = Result<T, DiagnosticBuilder<'a>>;
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// `PResult` is used a lot. Make sure it doesn't unintentionally get bigger.
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// (See also the comment on `DiagnosticBuilderInner`.)
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#[cfg(target_arch = "x86_64")]
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static_assert_size!(PResult<'_, bool>, 16);
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/// Collected spans during parsing for places where a certain feature was
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/// used and should be feature gated accordingly in `check_crate`.
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#[derive(Default)]
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