[CS] NFC: Factor out Solution::hasAppliedSelf

Author: hamishknight

include/swift/Sema/ConstraintSystem.h

@@ -6093,6 +6093,7 @@ bool isAutoClosureArgument(Expr *argExpr);
 /// parameter being applied, meaning that it's dropped from the type of the
 /// reference.
 bool hasAppliedSelf(ConstraintSystem &cs, const OverloadChoice &choice);
+bool hasAppliedSelf(const Solution &S, const OverloadChoice &choice);
 bool hasAppliedSelf(const OverloadChoice &choice,
                     llvm::function_ref<Type(Type)> getFixedType);
 

lib/Sema/CSDiagnostics.cpp

@@ -2831,10 +2831,7 @@ bool ContextualFailure::diagnoseAsError() {
     auto params = fnType->getParams();
 
     ParameterListInfo info(
-        params, choice,
-        hasAppliedSelf(overload->choice, [&solution](Type type) {
-          return solution.simplifyType(type);
-        }));
+        params, choice, hasAppliedSelf(solution, overload->choice));
     auto numMissingArgs = llvm::count_if(
         indices(params), [&info](const unsigned paramIdx) -> bool {
           return !info.hasDefaultArgument(paramIdx);

lib/Sema/ConstraintSystem.cpp

@@ -3891,6 +3891,13 @@ bool constraints::hasAppliedSelf(ConstraintSystem &cs,
   });
 }
 
+bool constraints::hasAppliedSelf(const Solution &S,
+                                 const OverloadChoice &choice) {
+  return hasAppliedSelf(choice, [&](Type type) -> Type {
+    return S.simplifyType(type);
+  });
+}
+
 bool constraints::hasAppliedSelf(const OverloadChoice &choice,
                                  llvm::function_ref<Type(Type)> getFixedType) {
   auto *decl = choice.getDeclOrNull();
@@ -4206,8 +4213,7 @@ Solution::getFunctionArgApplyInfo(ConstraintLocator *locator) const {
     fnInterfaceType = callee->getInterfaceType();
 
     // Strip off the curried self parameter if necessary.
-    if (hasAppliedSelf(
-            *choice, [this](Type type) -> Type { return simplifyType(type); }))
+    if (hasAppliedSelf(*this, *choice))
       fnInterfaceType = fnInterfaceType->castTo<AnyFunctionType>()->getResult();
 
 #ifndef NDEBUG