diff --git a/lib/addon.cc b/lib/addon.cc
index 7d0abc7..318250a 100644
--- a/lib/addon.cc
+++ b/lib/addon.cc
@@ -168,8 +168,8 @@ const StrVal& WrappedRE2::prepareArgument(const v8::Local<v8::Value> &arg, bool
 
 void StrVal::setIndex(size_t newIndex)
 {
-	isIndexValid = newIndex <= length;
-	if (!isIndexValid)
+	isValidIndex = newIndex <= length;
+	if (!isValidIndex)
 	{
 		index = newIndex;
 		byteIndex = 0;
diff --git a/lib/exec.cc b/lib/exec.cc
index e9d69f6..29729f8 100644
--- a/lib/exec.cc
+++ b/lib/exec.cc
@@ -19,7 +19,7 @@ NAN_METHOD(WrappedRE2::Exec)
 
 	if (re2->global || re2->sticky)
 	{
-		if (!str.isIndexValid)
+		if (!str.isValidIndex)
 		{
 			re2->lastIndex = 0;
 			info.GetReturnValue().SetNull();
diff --git a/lib/match.cc b/lib/match.cc
index 54babf0..59176dc 100644
--- a/lib/match.cc
+++ b/lib/match.cc
@@ -17,7 +17,7 @@ NAN_METHOD(WrappedRE2::Match)
 	auto str = re2->prepareArgument(info[0], re2->global);
 	if (str.isBad) return; // throws an exception
 
-	if (!str.isIndexValid)
+	if (!str.isValidIndex)
 	{
 		re2->lastIndex = 0;
 		info.GetReturnValue().SetNull();
diff --git a/lib/replace.cc b/lib/replace.cc
index 171ae03..c012e6c 100644
--- a/lib/replace.cc
+++ b/lib/replace.cc
@@ -500,7 +500,7 @@ NAN_METHOD(WrappedRE2::Replace)
 	auto replacee = re2->prepareArgument(info[0]);
 	if (replacee.isBad) return; // throws an exception
 
-	if (!replacee.isIndexValid)
+	if (!replacee.isValidIndex)
 	{
 		info.GetReturnValue().Set(info[0]);
 		return;
diff --git a/lib/test.cc b/lib/test.cc
index 66fe7bf..8abf584 100644
--- a/lib/test.cc
+++ b/lib/test.cc
@@ -23,7 +23,7 @@ NAN_METHOD(WrappedRE2::Test)
 		return;
 	}
 
-	if (!str.isIndexValid)
+	if (!str.isValidIndex)
 	{
 		re2->lastIndex = 0;
 		info.GetReturnValue().SetNull();
diff --git a/lib/wrapped_re2.h b/lib/wrapped_re2.h
index 22d43fa..6a6c1c3 100644
--- a/lib/wrapped_re2.h
+++ b/lib/wrapped_re2.h
@@ -9,9 +9,9 @@ struct StrVal
 	char *data;
 	size_t size, length;
 	size_t index, byteIndex;
-	bool isBuffer, isIndexValid, isBad;
+	bool isBuffer, isValidIndex, isBad;
 
-	StrVal() : data(NULL), size(0), length(0), index(0), byteIndex(0), isBuffer(false), isIndexValid(false), isBad(false) {}
+	StrVal() : data(NULL), size(0), length(0), index(0), byteIndex(0), isBuffer(false), isValidIndex(false), isBad(false) {}
 
 	operator re2::StringPiece() const { return re2::StringPiece(data, size); }
 
@@ -20,7 +20,7 @@ struct StrVal
 
 	void clear()
 	{
-		isBad = isBuffer = isIndexValid = false;
+		isBad = isBuffer = isValidIndex = false;
 		size = length = index = byteIndex = 0;
 		data = nullptr;
 	}