rustc_span: replace MacroBacktrace with ExpnData.

Author: eddyb

src/librustc_errors/emitter.rs

@@ -21,6 +21,7 @@ use crate::{
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::sync::Lrc;
+use rustc_span::hygiene::{ExpnKind, MacroKind};
 use std::borrow::Cow;
 use std::cmp::{max, min, Reverse};
 use std::io;
@@ -346,15 +347,15 @@ pub trait Emitter {
             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() {
+                if trace.def_site.is_dummy() {
                     continue;
                 }
                 if always_backtrace {
                     new_labels.push((
-                        trace.def_site_span,
+                        trace.def_site,
                         format!(
                             "in this expansion of `{}`{}",
-                            trace.macro_decl_name,
+                            trace.kind.descr(),
                             if backtrace_len > 2 {
                                 // if backtrace_len == 1 it'll be pointed
                                 // at by "in this macro invocation"
@@ -366,9 +367,8 @@ pub trait Emitter {
                     ));
                 }
                 // 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("#[")
+                if !sm.span_to_filename(trace.def_site).is_macros()
+                    && matches!(trace.kind, ExpnKind::Macro(MacroKind::Bang, _))
                     || always_backtrace
                 {
                     new_labels.push((

src/librustc_errors/json.rs

@@ -17,7 +17,8 @@ use crate::{Applicability, DiagnosticId};
 use crate::{CodeSuggestion, SubDiagnostic};
 
 use rustc_data_structures::sync::Lrc;
-use rustc_span::{MacroBacktrace, MultiSpan, Span, SpanLabel};
+use rustc_span::hygiene::ExpnData;
+use rustc_span::{MultiSpan, Span, SpanLabel};
 use std::io::{self, Write};
 use std::path::Path;
 use std::sync::{Arc, Mutex};
@@ -317,18 +318,18 @@ impl DiagnosticSpan {
         is_primary: bool,
         label: Option<String>,
         suggestion: Option<(&String, Applicability)>,
-        mut backtrace: vec::IntoIter<MacroBacktrace>,
+        mut backtrace: vec::IntoIter<ExpnData>,
         je: &JsonEmitter,
     ) -> DiagnosticSpan {
         let start = je.sm.lookup_char_pos(span.lo());
         let end = je.sm.lookup_char_pos(span.hi());
         let backtrace_step = backtrace.next().map(|bt| {
             let call_site = Self::from_span_full(bt.call_site, false, None, None, backtrace, je);
             let def_site_span =
-                Self::from_span_full(bt.def_site_span, false, None, None, vec![].into_iter(), je);
+                Self::from_span_full(bt.def_site, false, None, None, vec![].into_iter(), je);
             Box::new(DiagnosticSpanMacroExpansion {
                 span: call_site,
-                macro_decl_name: bt.macro_decl_name,
+                macro_decl_name: bt.kind.descr(),
                 def_site_span,
             })
         });

src/librustc_span/lib.rs

@@ -445,7 +445,7 @@ impl Span {
         self.ctxt().outer_expn_data().allow_internal_unsafe
     }
 
-    pub fn macro_backtrace(mut self) -> Vec<MacroBacktrace> {
+    pub fn macro_backtrace(mut self) -> Vec<ExpnData> {
         let mut prev_span = DUMMY_SP;
         let mut result = vec![];
         loop {
@@ -455,11 +455,7 @@ impl Span {
             }
             // Don't print recursive invocations.
             if !expn_data.call_site.source_equal(&prev_span) {
-                result.push(MacroBacktrace {
-                    call_site: expn_data.call_site,
-                    macro_decl_name: expn_data.kind.descr(),
-                    def_site_span: expn_data.def_site,
-                });
+                result.push(expn_data.clone());
             }
 
             prev_span = self;
@@ -1501,18 +1497,6 @@ pub struct FileLines {
 pub static SPAN_DEBUG: AtomicRef<fn(Span, &mut fmt::Formatter<'_>) -> fmt::Result> =
     AtomicRef::new(&(default_span_debug as fn(_, &mut fmt::Formatter<'_>) -> _));
 
-#[derive(Debug)]
-pub struct MacroBacktrace {
-    /// span where macro was applied to generate this code
-    pub call_site: Span,
-
-    /// name of macro that was applied (e.g., "foo!" or "#[derive(Eq)]")
-    pub macro_decl_name: String,
-
-    /// span where macro was defined (possibly dummy)
-    pub def_site_span: Span,
-}
-
 // _____________________________________________________________________________
 // SpanLinesError, SpanSnippetError, DistinctSources, MalformedSourceMapPositions
 //