diff --git a/lib/Sema/ConstraintSystem.cpp b/lib/Sema/ConstraintSystem.cpp
index e2579eae5e0..656d2c43c7b 100644
--- a/lib/Sema/ConstraintSystem.cpp
+++ b/lib/Sema/ConstraintSystem.cpp
@@ -2503,7 +2503,7 @@ bool ConstraintSystem::salvage(SmallVectorImpl<Solution> &viable, Expr *expr) {
         }
       }
 
-      if (diagnoseAmbiguity(expr, viable)) {
+      if (diagnoseAmbiguity(viable)) {
         return true;
       }
     }
@@ -2757,8 +2757,7 @@ static void extendPreorderIndexMap(
   expr->walk(traversal);
 }
 
-bool ConstraintSystem::diagnoseAmbiguity(Expr *expr,
-                                         ArrayRef<Solution> solutions) {
+bool ConstraintSystem::diagnoseAmbiguity(ArrayRef<Solution> solutions) {
   // Produce a diff of the solutions.
   SolutionDiff diff(solutions);
 
diff --git a/lib/Sema/ConstraintSystem.h b/lib/Sema/ConstraintSystem.h
index ba3647619f6..80aaba2865e 100644
--- a/lib/Sema/ConstraintSystem.h
+++ b/lib/Sema/ConstraintSystem.h
@@ -2104,7 +2104,7 @@ public:
   /// emits an error message.
   void diagnoseFailureForExpr(Expr *expr);
 
-  bool diagnoseAmbiguity(Expr *expr, ArrayRef<Solution> solutions);
+  bool diagnoseAmbiguity(ArrayRef<Solution> solutions);
   bool diagnoseAmbiguityWithFixes(ArrayRef<Solution> solutions);
 
   /// Give the deprecation warning for referring to a global function