Corrected autoclosure handling.

Set autoclosure discriminators and follow visit single expression by way
of visiting brace stmt.

Author: nate-chandler

lib/AST/ASTWalker.cpp

@@ -313,15 +313,6 @@ class Traversal : public ASTVisitor<Traversal, Expr*, Stmt*,
     PrettyStackTraceDecl debugStack("walking into body of", AFD);
 #endif
 
-    if (AFD->hasSingleExpressionBody()) {
-      if (auto body = AFD->getSingleExpressionBody()) {
-        if ((body = doIt(body)))
-          AFD->setSingleExpressionBody(body);
-        else
-          return true;
-      }
-    }
-
     bool WalkGenerics = AFD->getGenericParams() &&
         Walker.shouldWalkIntoGenericParams() &&
         // accessor generics are visited from the storage decl

lib/Sema/TypeCheckStmt.cpp

@@ -1946,6 +1946,7 @@ bool TypeChecker::typeCheckFunctionBodyUntil(FuncDecl *FD,
                              /*skipClosures*/false);
         if (E != FD->getSingleExpressionBody())
           FD->setSingleExpressionBody(E);
+        setAutoClosureDiscriminators(FD, BS);
         FD->setBody(BS);
         return false;
       } else {
@@ -1970,6 +1971,7 @@ bool TypeChecker::typeCheckFunctionBodyUntil(FuncDecl *FD,
                                   /*discardedExpr=*/false, 
                                   /*skipClosures*/false);
             BS->setElement(0, E);
+            setAutoClosureDiscriminators(FD, BS);
             FD->setBody(BS);
             return false;
           }
@@ -2002,6 +2004,7 @@ bool TypeChecker::typeCheckFunctionBodyUntil(FuncDecl *FD,
                                /*skipClosures*/false);
           if (E != FD->getSingleExpressionBody())
             FD->setSingleExpressionBody(E);
+          setAutoClosureDiscriminators(FD, BS);
           FD->setBody(BS);
         }
         return HadSalvageError;