Teach serialized diagnostics about notes without locations.

Along the way, improve a diagnostic for "previous declaration here" for implicit parameters.

Fixes <rdar://problem/13211384>.

llvm-svn: 175802

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -1090,6 +1090,7 @@ def note_field_decl : Note<"member is declared here">;
 def note_ivar_decl : Note<"instance variable is declared here">;
 def note_bitfield_decl : Note<"bit-field is declared here">;
 def note_previous_decl : Note<"%0 declared here">;
+def note_implicit_param_decl : Note<"%0 is an implicit parameter">;
 def note_member_synthesized_at : Note<
   "implicit default %select{constructor|copy constructor|move constructor|copy "
   "assignment operator|move assignment operator|destructor}0 for %1 first "

clang/lib/Frontend/SerializedDiagnosticPrinter.cpp

@@ -543,8 +543,18 @@ void SDiagsWriter::HandleDiagnostic(DiagnosticsEngine::Level DiagLevel,
     // Special-case diagnostics with no location. We may not have entered a
     // source file in this case, so we can't use the normal DiagnosticsRenderer
     // machinery.
+
+    // Make sure we bracket all notes as "sub-diagnostics".  This matches
+    // the behavior in SDiagsRenderer::emitDiagnostic().
+    if (DiagLevel == DiagnosticsEngine::Note)
+      EnterDiagBlock();
+
     EmitDiagnosticMessage(SourceLocation(), PresumedLoc(), DiagLevel,
                           State->diagBuf, 0, &Info);
+
+    if (DiagLevel == DiagnosticsEngine::Note)
+      ExitDiagBlock();
+
     return;
   }
 

clang/lib/Sema/SemaExpr.cpp

@@ -1672,9 +1672,14 @@ bool Sema::DiagnoseEmptyLookup(Scope *S, CXXScopeSpec &SS, LookupResult &R,
             << SS.getRange()
             << FixItHint::CreateReplacement(Corrected.getCorrectionRange(),
                                             CorrectedStr);
-        if (ND)
+        if (ND) {
-          Diag(ND->getLocation(), diag::note_previous_decl)
+          unsigned diag = isa<ImplicitParamDecl>(ND)
+            ? diag::note_implicit_param_decl
+            : diag::note_previous_decl;
+
+          Diag(ND->getLocation(), diag)
             << CorrectedQuotedStr;
+        }
 
         // Tell the callee to try to recover.
         return false;