diff --git a/swift/lib/AST/ASTDumper.cpp b/swift/lib/AST/ASTDumper.cpp
index 0e42ac1250e..c9243a0da8d 100644
--- a/swift/lib/AST/ASTDumper.cpp
+++ b/swift/lib/AST/ASTDumper.cpp
@@ -442,7 +442,7 @@ static StringRef getDumpString(RequirementKind kind) {
 static unsigned getDumpString(unsigned value) {
   return value;
 }
-static size_t getDumpString(size_t value) {
+static unsigned long getDumpString(unsigned long value) {
   return value;
 }