[AST] Remove CallerDefaultArgumentExpr

Now that we use DefaultArgumentExpr for both kinds
of default arguments, this is no longer needed.

Author: hamishknight

include/swift/AST/Expr.h

@@ -3916,44 +3916,6 @@ class DefaultArgumentExpr final : public Expr {
   }
 };
 
-/// An expression referring to a caller-side default argument left unspecified
-/// at the call site.
-///
-/// A CallerDefaultArgumentExpr must only appear as a direct child of a
-/// ParenExpr or a TupleExpr that is itself a call argument.
-///
-/// FIXME: This only exists to distinguish caller default arguments from arguments
-/// that were specified at the call site. Once we remove SanitizeExpr, we can remove
-/// this hack too.
-class CallerDefaultArgumentExpr final : public Expr {
-  /// The expression that is evaluated to produce the default argument value.
-  Expr *SubExpr;
-
-  /// The source location of the argument list.
-  SourceLoc Loc;
-
-public:
-  explicit CallerDefaultArgumentExpr(Expr *subExpr, SourceLoc loc, Type Ty)
-    : Expr(ExprKind::CallerDefaultArgument, /*Implicit=*/true, Ty),
-      SubExpr(subExpr), Loc(loc) { }
-
-  SourceRange getSourceRange() const {
-    return Loc;
-  }
-
-  Expr *getSubExpr() const {
-    return SubExpr;
-  }
-
-  void setSubExpr(Expr *subExpr) {
-    SubExpr = subExpr;
-  }
-
-  static bool classof(const Expr *E) {
-    return E->getKind() == ExprKind::CallerDefaultArgument;
-  }
-};
-
 /// ApplyExpr - Superclass of various function calls, which apply an argument to
 /// a function to get a result.
 class ApplyExpr : public Expr {

include/swift/AST/ExprNodes.def

@@ -127,7 +127,6 @@ EXPR(DynamicType, Expr)
 EXPR(RebindSelfInConstructor, Expr)
 EXPR(OpaqueValue, Expr)
 EXPR(DefaultArgument, Expr)
-EXPR(CallerDefaultArgument, Expr)
 EXPR(BindOptional, Expr)
 EXPR(OptionalEvaluation, Expr)
 EXPR(ForceValue, Expr)

lib/AST/ASTDumper.cpp

@@ -2494,12 +2494,6 @@ class PrintExpr : public ExprVisitor<PrintExpr> {
     PrintWithColorRAII(OS, ParenthesisColor) << ')';
   }
 
-  void visitCallerDefaultArgumentExpr(CallerDefaultArgumentExpr *E) {
-    printCommon(E, "caller_default_argument_expr");
-    printRec(E->getSubExpr());
-    PrintWithColorRAII(OS, ParenthesisColor) << ')';
-  }
-
   void printArgumentLabels(ArrayRef<Identifier> argLabels) {
     PrintWithColorRAII(OS, ArgumentsColor) << " arg_labels=";
     for (auto label : argLabels) {

lib/AST/ASTWalker.cpp

@@ -483,15 +483,6 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
 
   Expr *visitDefaultArgumentExpr(DefaultArgumentExpr *E) { return E; }
 
-  Expr *visitCallerDefaultArgumentExpr(CallerDefaultArgumentExpr *E) {
-    if (auto subExpr = doIt(E->getSubExpr())) {
-      E->setSubExpr(subExpr);
-      return E;
-    }
-
-    return nullptr;
-  }
-
   Expr *visitInterpolatedStringLiteralExpr(InterpolatedStringLiteralExpr *E) {
     if (auto oldAppendingExpr = E->getAppendingExpr()) {
       if (auto appendingExpr = doIt(oldAppendingExpr))

lib/AST/Expr.cpp

@@ -312,7 +312,6 @@ ConcreteDeclRef Expr::getReferencedDecl() const {
 
   NO_REFERENCE(OpaqueValue);
   NO_REFERENCE(DefaultArgument);
-  NO_REFERENCE(CallerDefaultArgument);
 
   PASS_THROUGH_REFERENCE(BindOptional, getSubExpr);
   PASS_THROUGH_REFERENCE(OptionalEvaluation, getSubExpr);
@@ -621,7 +620,6 @@ bool Expr::canAppendPostfixExpression(bool appendingPostfixOperator) const {
   case ExprKind::RebindSelfInConstructor:
   case ExprKind::OpaqueValue:
   case ExprKind::DefaultArgument:
-  case ExprKind::CallerDefaultArgument:
   case ExprKind::BindOptional:
   case ExprKind::OptionalEvaluation:
     return false;

lib/SILGen/ASTVisitor.h

@@ -60,11 +60,6 @@ class ASTVisitor : public swift::ASTVisitor<ImplClass,
     llvm_unreachable("DefaultArgumentExpr should not appear in this position");
   }
 
-  ExprRetTy visitCallerDefaultArgumentExpr(CallerDefaultArgumentExpr *E, Args... AA) {
-    return static_cast<ImplClass*>(this)->visit(E->getSubExpr(),
-                                                std::forward<Args>(AA)...);
-  }
-
   ExprRetTy visitVarargExpansionExpr(VarargExpansionExpr *E, Args... AA) {
     return static_cast<ImplClass*>(this)->visit(E->getSubExpr(),
                                                 std::forward<Args>(AA)...);

lib/Sema/CSApply.cpp

@@ -3014,10 +3014,6 @@ namespace {
       llvm_unreachable("Already type-checked");
     }
 
-    Expr *visitCallerDefaultArgumentExpr(CallerDefaultArgumentExpr *expr) {
-      llvm_unreachable("Already type-checked");
-    }
-
     Expr *visitApplyExpr(ApplyExpr *expr) {
       auto *calleeLoc = CalleeLocators[expr];
       assert(calleeLoc);

lib/Sema/CSGen.cpp

@@ -2510,10 +2510,6 @@ namespace {
       return expr->getType();
     }
 
-    Type visitCallerDefaultArgumentExpr(CallerDefaultArgumentExpr *expr) {
-      return expr->getType();
-    }
-
     Type visitApplyExpr(ApplyExpr *expr) {
       auto fnExpr = expr->getFn();
 
@@ -3454,8 +3450,7 @@ namespace {
     }
 
     bool isSyntheticArgumentExpr(const Expr *expr) {
-      if (isa<DefaultArgumentExpr>(expr) ||
-          isa<CallerDefaultArgumentExpr>(expr))
+      if (isa<DefaultArgumentExpr>(expr))
         return true;
 
       if (auto *varargExpr = dyn_cast<VarargExpansionExpr>(expr))
@@ -3909,8 +3904,7 @@ swift::getOriginalArgumentList(Expr *expr) {
   OriginalArgumentList result;
 
   auto add = [&](Expr *arg, Identifier label, SourceLoc labelLoc) {
-    if (isa<DefaultArgumentExpr>(arg) ||
-        isa<CallerDefaultArgumentExpr>(arg)) {
+    if (isa<DefaultArgumentExpr>(arg)) {
       return;
     }
 

lib/Sema/TypeCheckAvailability.cpp

@@ -1785,8 +1785,7 @@ static void fixItAvailableAttrRename(InFlightDiagnostic &diag,
   auto I = argumentLabelIDs.begin();
 
   auto updateLabelsForArg = [&](Expr *expr) -> bool {
-    if (isa<DefaultArgumentExpr>(expr) ||
-        isa<CallerDefaultArgumentExpr>(expr)) {
+    if (isa<DefaultArgumentExpr>(expr)) {
       // Defaulted: remove param label of it.
       if (I == argumentLabelIDs.end())
         return true;

lib/Sema/TypeCheckError.cpp

@@ -679,8 +679,7 @@ class ApplyClassifier {
   Classification classifyRethrowsArgument(Expr *arg, Type paramType) {
     arg = arg->getValueProvidingExpr();
 
-    if (isa<DefaultArgumentExpr>(arg) ||
-        isa<CallerDefaultArgumentExpr>(arg)) {
+    if (isa<DefaultArgumentExpr>(arg)) {
       return classifyArgumentByType(arg->getType(),
                                     PotentialReason::forDefaultArgument());
     }