Introduce a helper function, NFC.

Author: lattner

include/swift/AST/Expr.h

@@ -3176,7 +3176,8 @@ class ApplyExpr : public Expr {
 public:
   Expr *getFn() const { return Fn; }
   void setFn(Expr *e) { Fn = e; }
-
+  Expr *getSemanticFn() const { return Fn->getSemanticsProvidingExpr(); }
+  
   Expr *getArg() const { return ArgAndIsSuper.getPointer(); }
   void setArg(Expr *e) {
     assert((getKind() != ExprKind::Binary || isa<TupleExpr>(e)) &&

lib/AST/Decl.cpp

@@ -4709,7 +4709,7 @@ ConstructorDecl::getDelegatingOrChainedInitKind(DiagnosticEngine *diags,
       if (!apply)
         return { true, E };
 
-      auto Callee = apply->getFn()->getSemanticsProvidingExpr();
+      auto Callee = apply->getSemanticFn();
 
       Expr *arg;
 

lib/SILGen/SILGenApply.cpp

@@ -843,8 +843,7 @@ class SILGenApply : public Lowering::ExprVisitor<SILGenApply> {
         // actually be using the allocating constructor. Update the type
         // appropriately.
         // FIXME: Re-derive the type from the declaration + substitutions?
-        auto ctorRef = cast<OtherConstructorDeclRefExpr>(
-                         site->getFn()->getSemanticsProvidingExpr());
+        auto ctorRef = cast<OtherConstructorDeclRefExpr>(site->getSemanticFn());
         auto fnType = ctorRef->getType()->castTo<FunctionType>();
         auto selfTy = MetatypeType::get(
                         fnType->getInput()->getInOutObjectType());

lib/Sema/CSSimplify.cpp

@@ -2561,7 +2561,7 @@ getArgumentLabels(ConstraintSystem &cs, ConstraintLocatorBuilder locator) {
 
     if (parts.back().getKind() == ConstraintLocator::ApplyFunction) {
       if (auto applyExpr = dyn_cast<ApplyExpr>(anchor)) {
-        anchor = applyExpr->getFn()->getSemanticsProvidingExpr();
+        anchor = applyExpr->getSemanticFn();
       }
       parts.pop_back();
       continue;

lib/Sema/MiscDiagnostics.cpp

@@ -181,7 +181,7 @@ static void diagSyntacticUseRestrictions(TypeChecker &TC, const Expr *E,
     /// methods are fully applied when they can't support partial application.
     void checkInvalidPartialApplication(Expr *E) {
       if (auto AE = dyn_cast<ApplyExpr>(E)) {
-        Expr *fnExpr = AE->getFn()->getSemanticsProvidingExpr();
+        Expr *fnExpr = AE->getSemanticFn();
         if (auto forceExpr = dyn_cast<ForceValueExpr>(fnExpr))
           fnExpr = forceExpr->getSubExpr()->getSemanticsProvidingExpr();
         if (auto dotSyntaxExpr = dyn_cast<DotSyntaxBaseIgnoredExpr>(fnExpr))

lib/Sema/TypeCheckConstraints.cpp

@@ -779,7 +779,7 @@ namespace {
 
               // If the function being called is not our unresolved initializer
               // reference, we're done.
-              if (apply->getFn()->getSemanticsProvidingExpr() != unresolvedDot)
+              if (apply->getSemanticFn() != unresolvedDot)
                 break;
 
               foundApply = true;

lib/Sema/TypeCheckStmt.cpp

@@ -1327,7 +1327,7 @@ static bool checkSuperInit(TypeChecker &tc, ConstructorDecl *fromCtor,
                            ApplyExpr *apply, bool implicitlyGenerated) {
   // Make sure we are referring to a designated initializer.
   auto otherCtorRef = dyn_cast<OtherConstructorDeclRefExpr>(
-                        apply->getFn()->getSemanticsProvidingExpr());
+                        apply->getSemanticFn());
   if (!otherCtorRef)
     return false;
 
@@ -1463,8 +1463,7 @@ bool TypeChecker::typeCheckConstructorBodyUntil(ConstructorDecl *ctor,
 
         std::pair<bool, Expr *> walkToExprPre(Expr *E) override {
           if (auto apply = dyn_cast<ApplyExpr>(E)) {
-            if (isa<OtherConstructorDeclRefExpr>(
-                  apply->getFn()->getSemanticsProvidingExpr())) {
+            if (isa<OtherConstructorDeclRefExpr>(apply->getSemanticFn())) {
               Found = apply;
               return { false, E };
             }