Index: clang-tools-extra/trunk/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp
===================================================================
--- clang-tools-extra/trunk/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp
+++ clang-tools-extra/trunk/clang-apply-replacements/lib/Tooling/ApplyReplacements.cpp
@@ -125,7 +125,8 @@
 }
 
 /// \brief Extract replacements from collected TranslationUnitReplacements and
-/// TranslationUnitDiagnostics and group them per file.
+/// TranslationUnitDiagnostics and group them per file. Identical replacements
+/// from diagnostics are deduplicated.
 ///
 /// \param[in] TUs Collection of all found and deserialized
 /// TranslationUnitReplacements.
@@ -142,10 +143,20 @@
   llvm::DenseMap<const FileEntry *, std::vector<tooling::Replacement>>
       GroupedReplacements;
 
-  auto AddToGroup = [&](const tooling::Replacement &R) {
+  // Deduplicate identical replacements in diagnostics.
+  // FIXME: Find an efficient way to deduplicate on diagnostics level.
+  llvm::DenseMap<const FileEntry *, std::set<tooling::Replacement>>
+      DiagReplacements;
+
+  auto AddToGroup = [&](const tooling::Replacement &R, bool FromDiag) {
     // Use the file manager to deduplicate paths. FileEntries are
     // automatically canonicalized.
     if (const FileEntry *Entry = SM.getFileManager().getFile(R.getFilePath())) {
+      if (FromDiag) {
+        auto &Replaces = DiagReplacements[Entry];
+        if (!Replaces.insert(R).second)
+          return;
+      }
       GroupedReplacements[Entry].push_back(R);
     } else if (Warned.insert(R.getFilePath()).second) {
       errs() << "Described file '" << R.getFilePath()
@@ -155,13 +166,13 @@
 
   for (const auto &TU : TUs)
     for (const tooling::Replacement &R : TU.Replacements)
-      AddToGroup(R);
+      AddToGroup(R, false);
 
   for (const auto &TU : TUDs)
     for (const auto &D : TU.Diagnostics)
       for (const auto &Fix : D.Fix)
         for (const tooling::Replacement &R : Fix.second)
-          AddToGroup(R);
+          AddToGroup(R, true);
 
   // Sort replacements per file to keep consistent behavior when
   // clang-apply-replacements run on differents machine.
Index: clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/file1.yaml
===================================================================
--- clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/file1.yaml
+++ clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/file1.yaml
@@ -10,9 +10,5 @@
         Offset:          12
         Length:          0
         ReplacementText: '0'
-      - FilePath:        $(path)/identical.cpp
-        Offset:          12
-        Length:          0
-        ReplacementText: '0'
 ...
 
Index: clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/file2.yaml
===================================================================
--- clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/file2.yaml
+++ clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/file2.yaml
@@ -0,0 +1,14 @@
+---
+MainSourceFile:     identical.cpp
+Diagnostics:
+  - DiagnosticName: test-identical-insertion
+    Message: Fix
+    FilePath: $(path)/identical.cpp
+    FileOffset: 12
+    Replacements:
+      - FilePath:        $(path)/identical.cpp
+        Offset:          12
+        Length:          0
+        ReplacementText: '0'
+...
+
Index: clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/identical.cpp
===================================================================
--- clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/identical.cpp
+++ clang-tools-extra/trunk/test/clang-apply-replacements/Inputs/identical/identical.cpp
@@ -1,2 +1,2 @@
 class MyType {};
-// CHECK: class MyType00 {};
+// CHECK: class MyType0 {};
Index: clang-tools-extra/trunk/test/clang-apply-replacements/identical.cpp
===================================================================
--- clang-tools-extra/trunk/test/clang-apply-replacements/identical.cpp
+++ clang-tools-extra/trunk/test/clang-apply-replacements/identical.cpp
@@ -1,5 +1,6 @@
 // RUN: mkdir -p %T/Inputs/identical
 // RUN: grep -Ev "// *[A-Z-]+:" %S/Inputs/identical/identical.cpp > %T/Inputs/identical/identical.cpp
 // RUN: sed "s#\$(path)#%/T/Inputs/identical#" %S/Inputs/identical/file1.yaml > %T/Inputs/identical/file1.yaml
+// RUN: sed "s#\$(path)#%/T/Inputs/identical#" %S/Inputs/identical/file2.yaml > %T/Inputs/identical/file2.yaml
 // RUN: clang-apply-replacements %T/Inputs/identical
 // RUN: FileCheck -input-file=%T/Inputs/identical/identical.cpp %S/Inputs/identical/identical.cpp