2 files changed, 19 insertions, 4 deletions
diff --git a/clang/lib/Analysis/FormatString.cpp b/clang/lib/Analysis/FormatString.cpp
index 83d08b55427..0872e788c60 100644
--- a/clang/lib/Analysis/FormatString.cpp
+++ b/clang/lib/Analysis/FormatString.cpp
@@ -310,8 +310,13 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
       return Match;
 
     case AnyCharTy: {
-      if (const EnumType *ETy = argTy->getAs<EnumType>())
+      if (const EnumType *ETy = argTy->getAs<EnumType>()) {
+        // If the enum is incomplete we know nothing about the underlying type.
+        // Assume that it's 'int'.
+        if (!ETy->getDecl()->isComplete())
+          return NoMatch;
         argTy = ETy->getDecl()->getIntegerType();
+      }
 
       if (const BuiltinType *BT = argTy->getAs<BuiltinType>())
         switch (BT->getKind()) {
@@ -327,8 +332,14 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
     }
 
     case SpecificTy: {
-      if (const EnumType *ETy = argTy->getAs<EnumType>())
-        argTy = ETy->getDecl()->getIntegerType();
+      if (const EnumType *ETy = argTy->getAs<EnumType>()) {
+        // If the enum is incomplete we know nothing about the underlying type.
+        // Assume that it's 'int'.
+        if (!ETy->getDecl()->isComplete())
+          argTy = C.IntTy;
+        else
+          argTy = ETy->getDecl()->getIntegerType();
+      }
       argTy = C.getCanonicalType(argTy).getUnqualifiedType();
 
       if (T == argTy)
diff --git a/clang/lib/Analysis/ScanfFormatString.cpp b/clang/lib/Analysis/ScanfFormatString.cpp
index 82b038864c2..3b93f1a57f1 100644
--- a/clang/lib/Analysis/ScanfFormatString.cpp
+++ b/clang/lib/Analysis/ScanfFormatString.cpp
@@ -418,8 +418,12 @@ bool ScanfSpecifier::fixType(QualType QT, QualType RawQT,
   QualType PT = QT->getPointeeType();
 
   // If it's an enum, get its underlying type.
-  if (const EnumType *ETy = PT->getAs<EnumType>())
+  if (const EnumType *ETy = PT->getAs<EnumType>()) {
+    // Don't try to fix incomplete enums.
+    if (!ETy->getDecl()->isComplete())
+      return false;
     PT = ETy->getDecl()->getIntegerType();
+  }
 
   const BuiltinType *BT = PT->getAs<BuiltinType>();
   if (!BT)