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annotate-snippet emitter: Deal with multispans from macros, too
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This moves the two methods from the `EmitterWriter` impl to trait
default methods in the `Emitter` trait so that they can be re-used by
the `AnnotateSnippetEmitterWriter`.

Closes #61810
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@phansch
phansch committed Sep 5, 2019
1 parent f257c40 commit 159d249
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Showing 2 changed files with 137 additions and 126 deletions.
12 changes: 8 additions & 4 deletions src/librustc_errors/annotate_snippet_emitter_writer.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -30,10 +30,14 @@ pub struct AnnotateSnippetEmitterWriter {
impl Emitter for AnnotateSnippetEmitterWriter {
/// The entry point for the diagnostics generation
fn emit_diagnostic(&mut self, db: &DiagnosticBuilder<'_>) {
let children = db.children.clone();
let (primary_span, suggestions) = self.primary_span_formatted(&db);

// FIXME(#59346): Add `fix_multispans_in_std_macros` function from emitter.rs
let mut children = db.children.clone();
let (mut primary_span, suggestions) = self.primary_span_formatted(&db);

self.fix_multispans_in_std_macros(&self.source_map,
&mut primary_span,
&mut children,
&db.level,
db.handler.flags.external_macro_backtrace);

self.emit_messages_default(&db.level,
db.message(),
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251 changes: 129 additions & 122 deletions src/librustc_errors/emitter.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -247,14 +247,142 @@ pub trait Emitter {
(primary_span, &db.suggestions)
}
}

// This does a small "fix" for multispans by looking to see if it can find any that
// point directly at <*macros>. Since these are often difficult to read, this
// will change the span to point at the use site.
fn fix_multispans_in_std_macros(&self,
source_map: &Option<Lrc<SourceMapperDyn>>,
span: &mut MultiSpan,
children: &mut Vec<SubDiagnostic>,
level: &Level,
backtrace: bool) {
let mut spans_updated = self.fix_multispan_in_std_macros(source_map, span, backtrace);
for child in children.iter_mut() {
spans_updated |= self.fix_multispan_in_std_macros(
source_map,
&mut child.span,
backtrace
);
}
let msg = if level == &Error {
"this error originates in a macro outside of the current crate \
(in Nightly builds, run with -Z external-macro-backtrace \
for more info)".to_string()
} else {
"this warning originates in a macro outside of the current crate \
(in Nightly builds, run with -Z external-macro-backtrace \
for more info)".to_string()
};

if spans_updated {
children.push(SubDiagnostic {
level: Level::Note,
message: vec![
(msg,
Style::NoStyle),
],
span: MultiSpan::new(),
render_span: None,
});
}
}

// This "fixes" MultiSpans that contain Spans that are pointing to locations inside of
// <*macros>. Since these locations are often difficult to read, we move these Spans from
// <*macros> to their corresponding use site.
fn fix_multispan_in_std_macros(&self,
source_map: &Option<Lrc<SourceMapperDyn>>,
span: &mut MultiSpan,
always_backtrace: bool) -> bool {
let mut spans_updated = false;

if let Some(ref sm) = source_map {
let mut before_after: Vec<(Span, Span)> = vec![];
let mut new_labels: Vec<(Span, String)> = vec![];

// First, find all the spans in <*macros> and point instead at their use site
for sp in span.primary_spans() {
if sp.is_dummy() {
continue;
}
let call_sp = sm.call_span_if_macro(*sp);
if call_sp != *sp && !always_backtrace {
before_after.push((*sp, call_sp));
}
let backtrace_len = sp.macro_backtrace().len();
for (i, trace) in sp.macro_backtrace().iter().rev().enumerate() {
// Only show macro locations that are local
// and display them like a span_note
if trace.def_site_span.is_dummy() {
continue;
}
if always_backtrace {
new_labels.push((trace.def_site_span,
format!("in this expansion of `{}`{}",
trace.macro_decl_name,
if backtrace_len > 2 {
// if backtrace_len == 1 it'll be pointed
// at by "in this macro invocation"
format!(" (#{})", i + 1)
} else {
String::new()
})));
}
// Check to make sure we're not in any <*macros>
if !sm.span_to_filename(trace.def_site_span).is_macros() &&
!trace.macro_decl_name.starts_with("desugaring of ") &&
!trace.macro_decl_name.starts_with("#[") ||
always_backtrace {
new_labels.push((trace.call_site,
format!("in this macro invocation{}",
if backtrace_len > 2 && always_backtrace {
// only specify order when the macro
// backtrace is multiple levels deep
format!(" (#{})", i + 1)
} else {
String::new()
})));
if !always_backtrace {
break;
}
}
}
}
for (label_span, label_text) in new_labels {
span.push_span_label(label_span, label_text);
}
for sp_label in span.span_labels() {
if sp_label.span.is_dummy() {
continue;
}
if sm.span_to_filename(sp_label.span.clone()).is_macros() &&
!always_backtrace
{
let v = sp_label.span.macro_backtrace();
if let Some(use_site) = v.last() {
before_after.push((sp_label.span.clone(), use_site.call_site.clone()));
}
}
}
// After we have them, make sure we replace these 'bad' def sites with their use sites
for (before, after) in before_after {
span.replace(before, after);
spans_updated = true;
}
}

spans_updated
}
}

impl Emitter for EmitterWriter {
fn emit_diagnostic(&mut self, db: &DiagnosticBuilder<'_>) {
let mut children = db.children.clone();
let (mut primary_span, suggestions) = self.primary_span_formatted(&db);

self.fix_multispans_in_std_macros(&mut primary_span,
self.fix_multispans_in_std_macros(&self.sm,
&mut primary_span,
&mut children,
&db.level,
db.handler.flags.external_macro_backtrace);
Expand Down Expand Up @@ -919,127 +1047,6 @@ impl EmitterWriter {
max
}

// This "fixes" MultiSpans that contain Spans that are pointing to locations inside of
// <*macros>. Since these locations are often difficult to read, we move these Spans from
// <*macros> to their corresponding use site.
fn fix_multispan_in_std_macros(&mut self,
span: &mut MultiSpan,
always_backtrace: bool) -> bool {
let mut spans_updated = false;

if let Some(ref sm) = self.sm {
let mut before_after: Vec<(Span, Span)> = vec![];
let mut new_labels: Vec<(Span, String)> = vec![];

// First, find all the spans in <*macros> and point instead at their use site
for sp in span.primary_spans() {
if sp.is_dummy() {
continue;
}
let call_sp = sm.call_span_if_macro(*sp);
if call_sp != *sp && !always_backtrace {
before_after.push((*sp, call_sp));
}
let backtrace_len = sp.macro_backtrace().len();
for (i, trace) in sp.macro_backtrace().iter().rev().enumerate() {
// Only show macro locations that are local
// and display them like a span_note
if trace.def_site_span.is_dummy() {
continue;
}
if always_backtrace {
new_labels.push((trace.def_site_span,
format!("in this expansion of `{}`{}",
trace.macro_decl_name,
if backtrace_len > 2 {
// if backtrace_len == 1 it'll be pointed
// at by "in this macro invocation"
format!(" (#{})", i + 1)
} else {
String::new()
})));
}
// Check to make sure we're not in any <*macros>
if !sm.span_to_filename(trace.def_site_span).is_macros() &&
!trace.macro_decl_name.starts_with("desugaring of ") &&
!trace.macro_decl_name.starts_with("#[") ||
always_backtrace {
new_labels.push((trace.call_site,
format!("in this macro invocation{}",
if backtrace_len > 2 && always_backtrace {
// only specify order when the macro
// backtrace is multiple levels deep
format!(" (#{})", i + 1)
} else {
String::new()
})));
if !always_backtrace {
break;
}
}
}
}
for (label_span, label_text) in new_labels {
span.push_span_label(label_span, label_text);
}
for sp_label in span.span_labels() {
if sp_label.span.is_dummy() {
continue;
}
if sm.span_to_filename(sp_label.span.clone()).is_macros() &&
!always_backtrace
{
let v = sp_label.span.macro_backtrace();
if let Some(use_site) = v.last() {
before_after.push((sp_label.span.clone(), use_site.call_site.clone()));
}
}
}
// After we have them, make sure we replace these 'bad' def sites with their use sites
for (before, after) in before_after {
span.replace(before, after);
spans_updated = true;
}
}

spans_updated
}

// This does a small "fix" for multispans by looking to see if it can find any that
// point directly at <*macros>. Since these are often difficult to read, this
// will change the span to point at the use site.
fn fix_multispans_in_std_macros(&mut self,
span: &mut MultiSpan,
children: &mut Vec<SubDiagnostic>,
level: &Level,
backtrace: bool) {
let mut spans_updated = self.fix_multispan_in_std_macros(span, backtrace);
for child in children.iter_mut() {
spans_updated |= self.fix_multispan_in_std_macros(&mut child.span, backtrace);
}
let msg = if level == &Error {
"this error originates in a macro outside of the current crate \
(in Nightly builds, run with -Z external-macro-backtrace \
for more info)".to_string()
} else {
"this warning originates in a macro outside of the current crate \
(in Nightly builds, run with -Z external-macro-backtrace \
for more info)".to_string()
};

if spans_updated {
children.push(SubDiagnostic {
level: Level::Note,
message: vec![
(msg,
Style::NoStyle),
],
span: MultiSpan::new(),
render_span: None,
});
}
}

/// Adds a left margin to every line but the first, given a padding length and the label being
/// displayed, keeping the provided highlighting.
fn msg_to_buffer(&self,
Expand Down

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