Auto merge of #66364 - Centril:cleanup-macro-def, r=petrochenkov,eddyb

Cleanup `rmeta::MacroDef`

Avoid using rountrip parsing in the encoder and in `fn load_macro_untracked`.

The main reason I was interested in this was to remove `rustc_parse` as a dependency of `rustc_metadata` but it seems like this had other benefits as well.

Fixes #49511.

r? @eddyb
cc @matthewjasper @estebank @petrochenkov

Author: bors

Cargo.lock

@@ -3891,14 +3891,12 @@ dependencies = [
  "memmap",
  "rustc",
  "rustc_ast",
- "rustc_ast_pretty",
  "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",
  "rustc_expand",
  "rustc_hir",
  "rustc_index",
- "rustc_parse",
  "rustc_span",
  "rustc_target",
  "serialize",

src/librustc/dep_graph/dep_node.rs

@@ -111,6 +111,7 @@ macro_rules! define_dep_nodes {
     ) => (
         #[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord, Hash,
                  RustcEncodable, RustcDecodable)]
+        #[allow(non_camel_case_types)]
         pub enum DepKind {
             $($variant),*
         }
@@ -173,6 +174,7 @@ macro_rules! define_dep_nodes {
 
         pub struct DepConstructor;
 
+        #[allow(non_camel_case_types)]
         impl DepConstructor {
             $(
                 #[inline(always)]

src/librustc/lint.rs

@@ -344,15 +344,8 @@ pub fn in_external_macro(sess: &Session, span: Span) -> bool {
         ExpnKind::Root | ExpnKind::Desugaring(DesugaringKind::ForLoop) => false,
         ExpnKind::AstPass(_) | ExpnKind::Desugaring(_) => true, // well, it's "external"
         ExpnKind::Macro(MacroKind::Bang, _) => {
-            if expn_data.def_site.is_dummy() {
-                // Dummy span for the `def_site` means it's an external macro.
-                return true;
-            }
-            match sess.source_map().span_to_snippet(expn_data.def_site) {
-                Ok(code) => !code.starts_with("macro_rules"),
-                // No snippet means external macro or compiler-builtin expansion.
-                Err(_) => true,
-            }
+            // Dummy span for the `def_site` means it's an external macro.
+            expn_data.def_site.is_dummy() || sess.source_map().is_imported(expn_data.def_site)
         }
         ExpnKind::Macro(..) => true, // definitely a plugin
     }

src/librustc/middle/stability.rs

@@ -110,7 +110,7 @@ pub fn report_unstable(
     let span_key = msp.primary_span().and_then(|sp: Span| {
         if !sp.is_dummy() {
             let file = sm.lookup_char_pos(sp.lo()).file;
-            if file.name.is_macros() { None } else { Some(span) }
+            if file.is_imported() { None } else { Some(span) }
         } else {
             None
         }

src/librustc_errors/emitter.rs

@@ -414,22 +414,24 @@ pub trait Emitter {
     }
 
     // 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.
+    // point directly at external macros. Since these are often difficult to read,
+    // this will change the span to point at the use site.
     fn fix_multispans_in_extern_macros(
         &self,
         source_map: &Option<Lrc<SourceMap>>,
         span: &mut MultiSpan,
         children: &mut Vec<SubDiagnostic>,
     ) {
-        for span in iter::once(span).chain(children.iter_mut().map(|child| &mut child.span)) {
+        debug!("fix_multispans_in_extern_macros: before: span={:?} children={:?}", span, children);
+        for span in iter::once(&mut *span).chain(children.iter_mut().map(|child| &mut child.span)) {
             self.fix_multispan_in_extern_macros(source_map, span);
         }
+        debug!("fix_multispans_in_extern_macros: after: span={:?} children={:?}", span, children);
     }
 
-    // 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.
+    // This "fixes" MultiSpans that contain `Span`s pointing to locations inside of external macros.
+    // Since these locations are often difficult to read,
+    // we move these spans from the external macros to their corresponding use site.
     fn fix_multispan_in_extern_macros(
         &self,
         source_map: &Option<Lrc<SourceMap>>,
@@ -440,14 +442,14 @@ pub trait Emitter {
             None => return,
         };
 
-        // First, find all the spans in <*macros> and point instead at their use site
+        // First, find all the spans in external macros and point instead at their use site.
         let replacements: Vec<(Span, Span)> = span
             .primary_spans()
             .iter()
             .copied()
             .chain(span.span_labels().iter().map(|sp_label| sp_label.span))
             .filter_map(|sp| {
-                if !sp.is_dummy() && sm.span_to_filename(sp).is_macros() {
+                if !sp.is_dummy() && sm.is_imported(sp) {
                     let maybe_callsite = sp.source_callsite();
                     if sp != maybe_callsite {
                         return Some((sp, maybe_callsite));
@@ -457,7 +459,7 @@ pub trait Emitter {
             })
             .collect();
 
-        // After we have them, make sure we replace these 'bad' def sites with their use sites
+        // After we have them, make sure we replace these 'bad' def sites with their use sites.
         for (from, to) in replacements {
             span.replace(from, to);
         }
@@ -472,6 +474,7 @@ impl Emitter for EmitterWriter {
     fn emit_diagnostic(&mut self, diag: &Diagnostic) {
         let mut children = diag.children.clone();
         let (mut primary_span, suggestions) = self.primary_span_formatted(&diag);
+        debug!("emit_diagnostic: suggestions={:?}", suggestions);
 
         self.fix_multispans_in_extern_macros_and_render_macro_backtrace(
             &self.sm,
@@ -1533,6 +1536,7 @@ impl EmitterWriter {
 
         // Render the replacements for each suggestion
         let suggestions = suggestion.splice_lines(&**sm);
+        debug!("emit_suggestion_default: suggestions={:?}", suggestions);
 
         if suggestions.is_empty() {
             // Suggestions coming from macros can have malformed spans. This is a heavy handed

src/librustc_errors/json.rs

@@ -394,6 +394,11 @@ impl DiagnosticSpanLine {
         je.sm
             .span_to_lines(span)
             .map(|lines| {
+                // We can't get any lines if the source is unavailable.
+                if !je.sm.ensure_source_file_source_present(lines.file.clone()) {
+                    return vec![];
+                }
+
                 let sf = &*lines.file;
                 lines
                     .lines

src/librustc_errors/lib.rs

@@ -196,6 +196,11 @@ impl CodeSuggestion {
                 let lines = sm.span_to_lines(bounding_span).ok()?;
                 assert!(!lines.lines.is_empty());
 
+                // We can't splice anything if the source is unavailable.
+                if !sm.ensure_source_file_source_present(lines.file.clone()) {
+                    return None;
+                }
+
                 // To build up the result, we do this for each span:
                 // - push the line segment trailing the previous span
                 //   (at the beginning a "phantom" span pointing at the start of the line)

src/librustc_expand/mbe/macro_rules.rs

@@ -105,10 +105,10 @@ impl<'a> ParserAnyMacro<'a> {
             if e.span.is_dummy() {
                 // Get around lack of span in error (#30128)
                 e.replace_span_with(site_span);
-                if parser.sess.source_map().span_to_filename(arm_span).is_real() {
+                if !parser.sess.source_map().is_imported(arm_span) {
                     e.span_label(arm_span, "in this macro arm");
                 }
-            } else if !parser.sess.source_map().span_to_filename(parser.token.span).is_real() {
+            } else if parser.sess.source_map().is_imported(parser.token.span) {
                 e.span_label(site_span, "in this macro invocation");
             }
             match kind {
@@ -297,7 +297,7 @@ fn generic_extension<'cx>(
     let span = token.span.substitute_dummy(sp);
     let mut err = cx.struct_span_err(span, &parse_failure_msg(&token));
     err.span_label(span, label);
-    if !def_span.is_dummy() && cx.source_map().span_to_filename(def_span).is_real() {
+    if !def_span.is_dummy() && !cx.source_map().is_imported(def_span) {
         err.span_label(cx.source_map().def_span(def_span), "when calling this macro");
     }
 

src/librustc_macros/src/symbols.rs

@@ -103,6 +103,7 @@ pub fn symbols(input: TokenStream) -> TokenStream {
             #value,
         });
         keyword_stream.extend(quote! {
+            #[allow(non_upper_case_globals)]
             pub const #name: Symbol = Symbol::new(#counter);
         });
         counter += 1;
@@ -120,6 +121,8 @@ pub fn symbols(input: TokenStream) -> TokenStream {
             #value,
         });
         symbols_stream.extend(quote! {
+            #[allow(rustc::default_hash_types)]
+            #[allow(non_upper_case_globals)]
             pub const #name: Symbol = Symbol::new(#counter);
         });
         counter += 1;
@@ -149,6 +152,7 @@ pub fn symbols(input: TokenStream) -> TokenStream {
             () => {
                 #symbols_stream
 
+                #[allow(non_upper_case_globals)]
                 pub const digits_array: &[Symbol; 10] = &[
                     #digits_stream
                 ];

src/librustc_metadata/Cargo.toml

@@ -15,7 +15,6 @@ log = "0.4"
 memmap = "0.7"
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
 rustc = { path = "../librustc" }
-rustc_ast_pretty = { path = "../librustc_ast_pretty" }
 rustc_attr = { path = "../librustc_attr" }
 rustc_data_structures = { path = "../librustc_data_structures" }
 rustc_errors = { path = "../librustc_errors" }
@@ -26,7 +25,6 @@ rustc_serialize = { path = "../libserialize", package = "serialize" }
 stable_deref_trait = "1.0.0"
 rustc_ast = { path = "../librustc_ast" }
 rustc_expand = { path = "../librustc_expand" }
-rustc_parse = { path = "../librustc_parse" }
 rustc_span = { path = "../librustc_span" }
 
 [target.'cfg(windows)'.dependencies]