[AST] Remove now-unused ClosureExpr::setSingleExpressionBody().

Author: DougGregor

include/swift/AST/AnyFunctionRef.h

@@ -89,20 +89,6 @@ class AnyFunctionRef {
     return TheFunction.get<AbstractClosureExpr *>()->getSingleExpressionBody();
   }
 
-  void setSingleExpressionBody(Expr *expr) {
-    if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>()) {
-      AFD->setSingleExpressionBody(expr);
-      return;
-    }
-
-    auto ACE = TheFunction.get<AbstractClosureExpr *>();
-    if (auto CE = dyn_cast<ClosureExpr>(ACE)) {
-      CE->setSingleExpressionBody(expr);
-    } else {
-      cast<AutoClosureExpr>(ACE)->setBody(expr);
-    }
-  }
-
   Type getType() const {
     if (auto *AFD = TheFunction.dyn_cast<AbstractFunctionDecl *>())
       return AFD->getInterfaceType();

include/swift/AST/Expr.h

@@ -3891,13 +3891,6 @@ class ClosureExpr : public AbstractClosureExpr {
   /// Only valid when \c hasSingleExpressionBody() is true.
   Expr *getSingleExpressionBody() const;
 
-  /// Set the body for a closure that has a single expression as its
-  /// body.
-  ///
-  /// This routine cannot change whether a closure has a single expression as
-  /// its body; it can only update that expression.
-  void setSingleExpressionBody(Expr *NewBody);
-
   /// Is this a completely empty closure?
   bool hasEmptyBody() const;
 

lib/AST/Expr.cpp

@@ -1898,19 +1898,6 @@ Expr *ClosureExpr::getSingleExpressionBody() const {
   return body.get<Expr *>();
 }
 
-void ClosureExpr::setSingleExpressionBody(Expr *NewBody) {
-  assert(hasSingleExpressionBody() && "Not a single-expression body");
-  auto body = getBody()->getFirstElement();
-  if (auto stmt = body.dyn_cast<Stmt *>()) {
-    if (auto braceStmt = dyn_cast<BraceStmt>(stmt))
-      braceStmt->getFirstElement() = NewBody;
-    else
-      cast<ReturnStmt>(stmt)->setResult(NewBody);
-    return;
-  }
-  getBody()->setFirstElement(NewBody);
-}
-
 bool ClosureExpr::hasEmptyBody() const {
   return getBody()->empty();
 }