Show SyntaxContext in formatted Span debug output

Aaron1011 · Aaron1011 · commit 88262984eb62 · 2020-06-08T21:47:33.000-04:00
This is only really useful in debug messages, so I've switched to
calling `span_to_string` in any place that causes a `Span` to end up in
user-visible output.
diff --git a/src/librustc_interface/callbacks.rs b/src/librustc_interface/callbacks.rs
@@ -18,7 +18,7 @@ use std::fmt;
 fn span_debug(span: rustc_span::Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     tls::with_opt(|tcx| {
         if let Some(tcx) = tcx {
-            write!(f, "{}", tcx.sess.source_map().span_to_string(span))
+            rustc_span::debug_with_source_map(span, f, tcx.sess.source_map())
         } else {
             rustc_span::default_span_debug(span, f)
         }
diff --git a/src/librustc_middle/mir/mod.rs b/src/librustc_middle/mir/mod.rs
@@ -2449,7 +2449,8 @@ impl<'tcx> Debug for Rvalue<'tcx> {
                                     tcx.def_path_str_with_substs(def_id.to_def_id(), substs),
                                 )
                             } else {
-                                format!("[closure@{:?}]", tcx.hir().span(hir_id))
+                                let span = tcx.hir().span(hir_id);
+                                format!("[closure@{}]", tcx.sess.source_map().span_to_string(span))
                             };
                             let mut struct_fmt = fmt.debug_struct(&name);
 
diff --git a/src/librustc_middle/ty/print/pretty.rs b/src/librustc_middle/ty/print/pretty.rs
@@ -605,7 +605,8 @@ pub trait PrettyPrinter<'tcx>:
                 // FIXME(eddyb) should use `def_span`.
                 if let Some(did) = did.as_local() {
                     let hir_id = self.tcx().hir().as_local_hir_id(did);
-                    p!(write("@{:?}", self.tcx().hir().span(hir_id)));
+                    let span = self.tcx().hir().span(hir_id);
+                    p!(write("@{}", self.tcx().sess.source_map().span_to_string(span)));
 
                     if substs.as_generator().is_valid() {
                         let upvar_tys = substs.as_generator().upvar_tys();
@@ -653,7 +654,8 @@ pub trait PrettyPrinter<'tcx>:
                     if self.tcx().sess.opts.debugging_opts.span_free_formats {
                         p!(write("@"), print_def_path(did.to_def_id(), substs));
                     } else {
-                        p!(write("@{:?}", self.tcx().hir().span(hir_id)));
+                        let span = self.tcx().hir().span(hir_id);
+                        p!(write("@{}", self.tcx().sess.source_map().span_to_string(span)));
                     }
 
                     if substs.as_closure().is_valid() {
@@ -1362,7 +1364,7 @@ impl<F: fmt::Write> Printer<'tcx> for FmtPrinter<'_, 'tcx, F> {
                 if !self.empty_path {
                     write!(self, "::")?;
                 }
-                write!(self, "<impl at {:?}>", span)?;
+                write!(self, "<impl at {}>", self.tcx.sess.source_map().span_to_string(span))?;
                 self.empty_path = false;
 
                 return Ok(self);
diff --git a/src/librustc_mir/borrow_check/nll.rs b/src/librustc_mir/borrow_check/nll.rs
@@ -314,7 +314,7 @@ pub(super) fn dump_mir_results<'a, 'tcx>(
     infcx: &InferCtxt<'a, 'tcx>,
     source: MirSource<'tcx>,
     body: &Body<'tcx>,
-    regioncx: &RegionInferenceContext<'_>,
+    regioncx: &RegionInferenceContext<'tcx>,
     closure_region_requirements: &Option<ClosureRegionRequirements<'_>>,
 ) {
     if !mir_util::dump_enabled(infcx.tcx, "nll", source.def_id()) {
@@ -325,7 +325,7 @@ pub(super) fn dump_mir_results<'a, 'tcx>(
         match pass_where {
             // Before the CFG, dump out the values for each region variable.
             PassWhere::BeforeCFG => {
-                regioncx.dump_mir(out)?;
+                regioncx.dump_mir(infcx.tcx, out)?;
                 writeln!(out, "|")?;
 
                 if let Some(closure_region_requirements) = closure_region_requirements {
diff --git a/src/librustc_mir/borrow_check/region_infer/dump_mir.rs b/src/librustc_mir/borrow_check/region_infer/dump_mir.rs
@@ -4,7 +4,9 @@
 //! context internal state.
 
 use super::{OutlivesConstraint, RegionInferenceContext};
+use crate::borrow_check::type_check::Locations;
 use rustc_infer::infer::NLLRegionVariableOrigin;
+use rustc_middle::ty::TyCtxt;
 use std::io::{self, Write};
 
 // Room for "'_#NNNNr" before things get misaligned.
@@ -14,7 +16,7 @@ const REGION_WIDTH: usize = 8;
 
 impl<'tcx> RegionInferenceContext<'tcx> {
     /// Write out our state into the `.mir` files.
-    pub(crate) fn dump_mir(&self, out: &mut dyn Write) -> io::Result<()> {
+    pub(crate) fn dump_mir(&self, tcx: TyCtxt<'tcx>, out: &mut dyn Write) -> io::Result<()> {
         writeln!(out, "| Free Region Mapping")?;
 
         for region in self.regions() {
@@ -48,7 +50,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
 
         writeln!(out, "|")?;
         writeln!(out, "| Inference Constraints")?;
-        self.for_each_constraint(&mut |msg| writeln!(out, "| {}", msg))?;
+        self.for_each_constraint(tcx, &mut |msg| writeln!(out, "| {}", msg))?;
 
         Ok(())
     }
@@ -59,6 +61,7 @@ impl<'tcx> RegionInferenceContext<'tcx> {
     /// inference resulted in the values that it did when debugging.
     fn for_each_constraint(
         &self,
+        tcx: TyCtxt<'tcx>,
         with_msg: &mut dyn FnMut(&str) -> io::Result<()>,
     ) -> io::Result<()> {
         for region in self.definitions.indices() {
@@ -72,7 +75,11 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         constraints.sort();
         for constraint in &constraints {
             let OutlivesConstraint { sup, sub, locations, category } = constraint;
-            with_msg(&format!("{:?}: {:?} due to {:?} at {:?}", sup, sub, category, locations,))?;
+            let (name, arg) = match locations {
+                Locations::All(span) => ("All", tcx.sess.source_map().span_to_string(*span)),
+                Locations::Single(loc) => ("Single", format!("{:?}", loc)),
+            };
+            with_msg(&format!("{:?}: {:?} due to {:?} at {}({})", sup, sub, category, name, arg))?;
         }
 
         Ok(())
diff --git a/src/librustc_mir/util/pretty.rs b/src/librustc_mir/util/pretty.rs
@@ -135,7 +135,7 @@ fn dump_matched_mir_node<'tcx, F>(
         }
         writeln!(file)?;
         extra_data(PassWhere::BeforeCFG, &mut file)?;
-        write_user_type_annotations(body, &mut file)?;
+        write_user_type_annotations(tcx, body, &mut file)?;
         write_mir_fn(tcx, source, body, &mut extra_data, &mut file)?;
         extra_data(PassWhere::AfterCFG, &mut file)?;
     };
@@ -351,7 +351,7 @@ fn write_extra<'tcx, F>(tcx: TyCtxt<'tcx>, write: &mut dyn Write, mut visit_op:
 where
     F: FnMut(&mut ExtraComments<'tcx>),
 {
-    let mut extra_comments = ExtraComments { _tcx: tcx, comments: vec![] };
+    let mut extra_comments = ExtraComments { tcx, comments: vec![] };
     visit_op(&mut extra_comments);
     for comment in extra_comments.comments {
         writeln!(write, "{:A$} // {}", "", comment, A = ALIGN)?;
@@ -360,7 +360,7 @@ where
 }
 
 struct ExtraComments<'tcx> {
-    _tcx: TyCtxt<'tcx>, // don't need it now, but bet we will soon
+    tcx: TyCtxt<'tcx>,
     comments: Vec<String>,
 }
 
@@ -377,7 +377,7 @@ impl Visitor<'tcx> for ExtraComments<'tcx> {
         self.super_constant(constant, location);
         let Constant { span, user_ty, literal } = constant;
         self.push("mir::Constant");
-        self.push(&format!("+ span: {:?}", span));
+        self.push(&format!("+ span: {}", self.tcx.sess.source_map().span_to_string(*span)));
         if let Some(user_ty) = user_ty {
             self.push(&format!("+ user_ty: {:?}", user_ty));
         }
@@ -862,12 +862,22 @@ fn write_mir_sig(
     Ok(())
 }
 
-fn write_user_type_annotations(body: &Body<'_>, w: &mut dyn Write) -> io::Result<()> {
+fn write_user_type_annotations(
+    tcx: TyCtxt<'_>,
+    body: &Body<'_>,
+    w: &mut dyn Write,
+) -> io::Result<()> {
     if !body.user_type_annotations.is_empty() {
         writeln!(w, "| User Type Annotations")?;
     }
     for (index, annotation) in body.user_type_annotations.iter_enumerated() {
-        writeln!(w, "| {:?}: {:?} at {:?}", index.index(), annotation.user_ty, annotation.span)?;
+        writeln!(
+            w,
+            "| {:?}: {:?} at {}",
+            index.index(),
+            annotation.user_ty,
+            tcx.sess.source_map().span_to_string(annotation.span)
+        )?;
     }
     if !body.user_type_annotations.is_empty() {
         writeln!(w, "|")?;
diff --git a/src/librustc_span/lib.rs b/src/librustc_span/lib.rs
@@ -726,10 +726,18 @@ pub fn with_source_map<T, F: FnOnce() -> T>(source_map: Lrc<SourceMap>, f: F) ->
     f()
 }
 
+pub fn debug_with_source_map(
+    span: Span,
+    f: &mut fmt::Formatter<'_>,
+    source_map: &SourceMap,
+) -> fmt::Result {
+    write!(f, "{} ({:?})", source_map.span_to_string(span), span.ctxt())
+}
+
 pub fn default_span_debug(span: Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {
     GLOBALS.with(|globals| {
         if let Some(source_map) = &*globals.source_map.borrow() {
-            write!(f, "{}", source_map.span_to_string(span))
+            debug_with_source_map(span, f, source_map)
         } else {
             f.debug_struct("Span")
                 .field("lo", &span.lo())
diff --git a/src/test/ui/proc-macro/debug/dump-debug-span-debug.stderr b/src/test/ui/proc-macro/debug/dump-debug-span-debug.stderr

Original file line number	Diff line number	Diff line change
`@@ -18,7 +18,7 @@ use std::fmt;`
`18`	`18`	`fn span_debug(span: rustc_span::Span, f: &mut fmt::Formatter<'_>) -> fmt::Result {`
`19`	`19`	`tls::with_opt(\|tcx\| {`
`20`	`20`	`if let Some(tcx) = tcx {`
`21`		`- write!(f, "{}", tcx.sess.source_map().span_to_string(span))`
	`21`	`+ rustc_span::debug_with_source_map(span, f, tcx.sess.source_map())`
`22`	`22`	`} else {`
`23`	`23`	`rustc_span::default_span_debug(span, f)`
`24`	`24`	`}`
Original file line number	Diff line number	Diff line change
`@@ -2449,7 +2449,8 @@ impl<'tcx> Debug for Rvalue<'tcx> {`
`2449`	`2449`	`tcx.def_path_str_with_substs(def_id.to_def_id(), substs),`
`2450`	`2450`	`)`
`2451`	`2451`	`} else {`
`2452`		`- format!("[closure@{:?}]", tcx.hir().span(hir_id))`
	`2452`	`+ let span = tcx.hir().span(hir_id);`
	`2453`	`+ format!("[closure@{}]", tcx.sess.source_map().span_to_string(span))`
`2453`	`2454`	`};`
`2454`	`2455`	`let mut struct_fmt = fmt.debug_struct(&name);`
`2455`	`2456`