Fix lookupVisibleDecls from inside an AutoClosureExpr.

Author: rjmccall

lib/AST/LookupVisibleDecls.cpp

@@ -799,9 +799,8 @@ void swift::lookupVisibleDecls(VisibleDeclConsumer &Consumer,
 
       // Look in the generic parameters after checking our local declaration.
       GenericParams = AFD->getGenericParams();
-    } else if (auto ACE = dyn_cast<AbstractClosureExpr>(DC)) {
+    } else if (auto CE = dyn_cast<ClosureExpr>(DC)) {
       if (Loc.isValid()) {
-        auto CE = cast<ClosureExpr>(ACE);
         namelookup::FindLocalVal(SM, Loc, Consumer).visit(CE->getBody());
         if (auto P = CE->getParameters()) {
           namelookup::FindLocalVal(SM, Loc, Consumer).checkParameterList(P);

validation-test/compiler_crashers/28297-swift-lookupvisibledecls.swift renamed to validation-test/compiler_crashers_fixed/28297-swift-lookupvisibledecls.swift

@@ -5,6 +5,6 @@
 // See http://swift.org/LICENSE.txt for license information
 // See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// RUN: not --crash %target-swift-frontend %s -parse
+// RUN: not %target-swift-frontend %s -parse
 // REQUIRES: asserts
 {} ?? {let a{p