[ConstraintSystem] Adding new score kind SK_FunctionToAutoClosureConversion to increase impact of a function to autoclosure

Author: LucianoPAlmeida

include/swift/Sema/ConstraintSystem.h

@@ -802,8 +802,10 @@ enum ScoreKind {
   SK_KeyPathSubscript,
   /// A conversion from a string, array, or inout to a pointer.
   SK_ValueToPointerConversion,
+  /// A closure/function conversion to an autoclosure parameter.
+  SK_FunctionToAutoClosureConversion,
 
-  SK_LastScoreKind = SK_ValueToPointerConversion,
+  SK_LastScoreKind = SK_FunctionToAutoClosureConversion,
 };
 
 /// The number of score kinds.

lib/Sema/CSRanking.cpp

@@ -81,6 +81,9 @@ static StringRef getScoreKindName(ScoreKind kind) {
 
   case SK_ValueToPointerConversion:
     return "value-to-pointer conversion";
+
+  case SK_FunctionToAutoClosureConversion:
+    return "function to autoclosure parameter";
   }
 }
 

lib/Sema/CSSimplify.cpp

@@ -1355,7 +1355,7 @@ ConstraintSystem::TypeMatchResult constraints::matchCallArguments(
         //
         //    f { } // OK
         if (isExpr<ClosureExpr>(argExpr)) {
-          cs.increaseScore(SK_FunctionConversion);
+          cs.increaseScore(SK_FunctionToAutoClosureConversion);
         }
 
         // If the argument is not marked as @autoclosure or
@@ -2233,7 +2233,7 @@ ConstraintSystem::matchFunctionTypes(FunctionType *func1, FunctionType *func2,
     if (func1Param.isAutoClosure() &&
         (!func2Param.isAutoClosure() &&
          func2Param.getPlainType()->is<FunctionType>())) {
-      increaseScore(SK_FunctionConversion);
+      increaseScore(SK_FunctionToAutoClosureConversion);
     }
 
     // Variadic bit must match.