Fix NPE in CFAbstractValue

checker/tests/resourceleak/Issue7217.java

@@ -0,0 +1,9 @@
+import java.util.Collection;
+
+// Test case to show fix for https://github.com/typetools/checker-framework/issues/7217
+class Issue7217<E extends Enum<E>> {
+
+  void test(boolean b, Collection<E> c1, Collection<E> c2) {
+    Object x = b ? c1 : c2;
+  }
+}

docs/manual/contributors.tex

@@ -141,6 +141,7 @@
 Steph Dietzel,
 Stephan Schroevers,
 Stuart Pernsteiner,
+Suvrat Acharya,
 Suzanne Millstein,
 Thomas Schweizer,
 Thomas Wei\ss schuh,

framework/src/main/java/org/checkerframework/framework/flow/CFAbstractValue.java

@@ -404,6 +404,9 @@ private final AnnotationMirror lowestQualifier(AnnotationMirror qual1, Annotatio
         AnnotatedTypeVariable typeVar,
         AnnotationMirror top,
         boolean canCombinedSetBeMissingAnnos) {
+      if (typeVar == null) {
+        return annotation;
+      }
 
       AnnotationMirror upperBound = typeVar.getAnnotationInHierarchy(top);
       TypeMirror upperBoundTM = typeVar.getUpperBound().getUnderlyingType();
@@ -590,6 +593,9 @@ public ValueLub(boolean shouldWiden) {
         AnnotatedTypeVariable typeVar,
         AnnotationMirror top,
         boolean canCombinedSetBeMissingAnnos) {
+      if (typeVar == null) {
+        return annotation;
+      }
       TypeMirror typeVarTM = typeVar.getUnderlyingType();
       if (canCombinedSetBeMissingAnnos) {
         // anno is the primary annotation on the use of a type variable. typeVar is a use of
@@ -695,6 +701,9 @@ protected class ValueGlb extends AnnotationSetCombiner {
         AnnotatedTypeVariable typeVar,
         AnnotationMirror top,
         boolean canCombinedSetBeMissingAnnos) {
+      if (typeVar == null) {
+        return annotation;
+      }
       TypeMirror typeVarTM = typeVar.getUnderlyingType();
       if (canCombinedSetBeMissingAnnos) {
         // anno is the primary annotation on the use of a type variable. typeVar is a use of