Index: clang/lib/AST/ASTContext.cpp
===================================================================
--- clang/lib/AST/ASTContext.cpp
+++ clang/lib/AST/ASTContext.cpp
@@ -99,7 +99,7 @@
 };
 
 static llvm::Optional<SourceLocation>
-getCandidateCommentLocation(SourceManager &SrcMgr, const Decl *D) {
+getDeclLocationForCommentSearch(SourceManager &SrcMgr, const Decl *D) {
   // Find declaration location.
   // For Objective-C declarations we generally don't expect to have multiple
   // declarators, thus use declaration starting location as the "declaration
@@ -140,20 +140,20 @@
   return DeclLoc;
 };
 
-// Assumes the comment is the closest comment before the decl - i. e. there's no
-// other comment between them.
-static bool IsCommentBeforeDecl(SourceManager &SrcMgr,
-                                std::pair<FileID, unsigned> CommentEndLoc,
-                                std::pair<FileID, unsigned> DeclLoc) {
+// Returns true if the comment which ends at CommentEndLoc is attached to the
+// declaration at DeclLoc. The comment must be the closest one before the
+// declaration (no other comments in between).
+static bool IsCommentAttachedToDecl(SourceManager &SrcMgr,
+                                    std::pair<FileID, unsigned> CommentEndLoc,
+                                    std::pair<FileID, unsigned> DeclLoc) {
+  // We're looking for comments that are BEFORE this declaration
+  assert(CommentEndLoc.second < DeclLoc.second);
+
   // If the comment and the declaration aren't in the same file, then they
   // aren't related.
   if (CommentEndLoc.first != DeclLoc.first)
     return false;
 
-  // We're looking for comments that are BEFORE this declaration
-  if (CommentEndLoc.second > DeclLoc.second)
-    return false;
-
   // Get the corresponding buffer.
   bool Invalid = false;
   const char *Buffer = SrcMgr.getBufferData(DeclLoc.first, &Invalid).data();
@@ -172,7 +172,7 @@
     return false;
 
   return true;
-};
+}
 
 /// Returns true iff \param D can have a documentation comment attached.
 static bool CanDeclHaveDocComment(const Decl *D) {
@@ -242,13 +242,13 @@
   if (!CanDeclHaveDocComment(D))
     return nullptr;
 
-  const llvm::Optional<SourceLocation> OptCandidateCommentLocation =
-      getCandidateCommentLocation(SourceMgr, D);
-  if (!OptCandidateCommentLocation)
+  const llvm::Optional<SourceLocation> OptDeclLocForCommentSearch =
+      getDeclLocationForCommentSearch(SourceMgr, D);
+  if (!OptDeclLocForCommentSearch)
     return nullptr;
 
-  const SourceLocation &CandidateCommentLocation =
-      OptCandidateCommentLocation.getValue();
+  const SourceLocation &DeclLocForCommentSearch =
+      OptDeclLocForCommentSearch.getValue();
 
   if (!CommentsLoaded && ExternalSource) {
     ExternalSource->ReadComments();
@@ -274,8 +274,7 @@
     // When searching for comments during parsing, the comment we are looking
     // for is usually among the last two comments we parsed -- check them
     // first.
-    RawComment CommentAtDeclLoc(SourceMgr,
-                                SourceRange(CandidateCommentLocation),
+    RawComment CommentAtDeclLoc(SourceMgr, SourceRange(DeclLocForCommentSearch),
                                 LangOpts.CommentOpts, false);
     BeforeThanCompare<RawComment> Compare(SourceMgr);
     ArrayRef<RawComment *>::iterator MaybeBeforeDecl = RawComments.end() - 1;
@@ -306,7 +305,7 @@
       (isa<FieldDecl>(D) || isa<EnumConstantDecl>(D) || isa<VarDecl>(D) ||
        isa<ObjCMethodDecl>(D) || isa<ObjCPropertyDecl>(D))) {
 
-    OptDeclLocDecomp = SourceMgr.getDecomposedLoc(CandidateCommentLocation);
+    OptDeclLocDecomp = SourceMgr.getDecomposedLoc(DeclLocForCommentSearch);
     const std::pair<FileID, unsigned> &DeclLocDecomp =
         OptDeclLocDecomp.getValue();
 
@@ -335,14 +334,14 @@
     return nullptr;
 
   if (!OptDeclLocDecomp)
-    OptDeclLocDecomp = SourceMgr.getDecomposedLoc(CandidateCommentLocation);
+    OptDeclLocDecomp = SourceMgr.getDecomposedLoc(DeclLocForCommentSearch);
   const std::pair<FileID, unsigned> &DeclLocDecomp =
       OptDeclLocDecomp.getValue();
 
   std::pair<FileID, unsigned> CommentEndDecomp
     = SourceMgr.getDecomposedLoc((*Comment)->getSourceRange().getEnd());
 
-  if (!IsCommentBeforeDecl(SourceMgr, CommentEndDecomp, DeclLocDecomp))
+  if (!IsCommentAttachedToDecl(SourceMgr, CommentEndDecomp, DeclLocDecomp))
     return nullptr;
 
   return *Comment;