protect against NPE for inheritance and annotation style

org.aspectj.ajdt.core/src/main/java/org/aspectj/ajdt/internal/compiler/lookup/EclipseSourceType.java

 			} else {
 				kind = null;
 			}
-		} else if (binding instanceof SourceTypeBinding) {
+		} else if (binding instanceof SourceTypeBinding && ((SourceTypeBinding)binding).scope != null) {
 			SourceTypeBinding sourceSc = (SourceTypeBinding) binding;
 			if (sourceSc.scope.referenceContext instanceof AspectDeclaration) {
 				// code style
 				kind = ((AspectDeclaration) sourceSc.scope.referenceContext).perClause.getKind();
-			} else { // if (sourceSc.scope.referenceContext instanceof
-				// TypeDeclaration) {
+			} else { // if (sourceSc.scope.referenceContext instanceof TypeDeclaration) {
 				// if @Aspect: perFromSuper, else if @Aspect(..) get from anno
 				// value, else null
 				kind = getPerClauseForTypeDeclaration((sourceSc.scope.referenceContext));