implemented code review

Author: Virgil Palanciuc

src/librustc/middle/stability.rs

@@ -18,6 +18,7 @@ use hir::def::Def;
 use hir::def_id::{CrateNum, CRATE_DEF_INDEX, DefId, LOCAL_CRATE};
 use ty::{self, TyCtxt};
 use middle::privacy::AccessLevels;
+use session::DiagnosticMessageId;
 use syntax::symbol::Symbol;
 use syntax_pos::{Span, MultiSpan, DUMMY_SP};
 use syntax::ast;
@@ -601,27 +602,25 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
 
                 let msp: MultiSpan = span.into();
                 let cm = &self.sess.parse_sess.codemap();
-                let span_key =
-                    msp.primary_span().and_then(|sp:Span|
-                        if sp != DUMMY_SP {
-                            let fname = cm.lookup_char_pos(sp.lo()).file.as_ref().name.clone();
-                            if fname.starts_with("<") && fname.ends_with(" macros>") {
-                                None
-                            } else {
-                                Some(span)
-                            }
-                        } else {
+                let span_key = msp.primary_span().and_then(|sp: Span|
+                    if sp != DUMMY_SP {
+                        let file = cm.lookup_char_pos(sp.lo()).file;
+                        if file.name.starts_with("<") && file.name.ends_with(" macros>") {
                             None
+                        } else {
+                            Some(span)
                         }
-                    );
+                    } else {
+                        None
+                    }
+                );
 
-                let tuple = (None, span_key, msg.clone());
-                let fresh = self.sess.one_time_diagnostics.borrow_mut().insert(tuple);
+                let error_id = (DiagnosticMessageId::StabilityId(issue), span_key, msg.clone());
+                let fresh = self.sess.one_time_diagnostics.borrow_mut().insert(error_id);
                 if fresh {
                     emit_feature_err(&self.sess.parse_sess, &feature.as_str(), span,
                                      GateIssue::Library(Some(issue)), &msg);
                 }
-
             }
             Some(_) => {
                 // Stable APIs are always ok to call and deprecated APIs are

src/librustc/session/mod.rs

@@ -75,10 +75,10 @@ pub struct Session {
     pub working_dir: (String, bool),
     pub lint_store: RefCell<lint::LintStore>,
     pub buffered_lints: RefCell<Option<lint::LintBuffer>>,
-    /// Set of (LintId, Option<Span>, message) tuples tracking lint
+    /// Set of (DiagnosticId, Option<Span>, message) tuples tracking
     /// (sub)diagnostics that have been set once, but should not be set again,
-    /// in order to avoid redundantly verbose output (Issue #24690).
-    pub one_time_diagnostics: RefCell<FxHashSet<(Option<lint::LintId>, Option<Span>, String)>>,
+    /// in order to avoid redundantly verbose output (Issue #24690, #44953).
+    pub one_time_diagnostics: RefCell<FxHashSet<(DiagnosticMessageId, Option<Span>, String)>>,
     pub plugin_llvm_passes: RefCell<Vec<String>>,
     pub plugin_attributes: RefCell<Vec<(String, AttributeType)>>,
     pub crate_types: RefCell<Vec<config::CrateType>>,
@@ -164,6 +164,13 @@ enum DiagnosticBuilderMethod {
     // add more variants as needed to support one-time diagnostics
 }
 
+/// Diagnostic message id - used in order to avoid emitting the same message more than once
+#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
+pub enum DiagnosticMessageId {
+    LintId(lint::LintId),
+    StabilityId(u32)
+}
+
 impl Session {
     pub fn local_crate_disambiguator(&self) -> CrateDisambiguator {
         match *self.crate_disambiguator.borrow() {
@@ -361,7 +368,7 @@ impl Session {
             },
             _ => {
                 let lint_id = lint::LintId::of(lint);
-                let id_span_message = (Some(lint_id), span, message.to_owned());
+                let id_span_message = (DiagnosticMessageId::LintId(lint_id), span, message.to_owned());
                 let fresh = self.one_time_diagnostics.borrow_mut().insert(id_span_message);
                 if fresh {
                     do_method()