Add downcast to CF

checker/src/main/java/org/checkerframework/checker/index/inequality/LessThanVisitor.java

@@ -113,7 +113,8 @@ protected void commonAssignmentCheck(
     }
 
     @Override
-    protected boolean isTypeCastSafe(AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
+    protected CastSafeKind isTypeCastSafe(
+            AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
 
         AnnotationMirror exprLTAnno =
                 exprType.getEffectiveAnnotationInHierarchy(atypeFactory.LESS_THAN_UNKNOWN);

checker/src/main/java/org/checkerframework/checker/interning/InterningVisitor.java

@@ -977,9 +977,10 @@ DeclaredType typeToCheck() {
     }
 
     @Override
-    protected boolean isTypeCastSafe(AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
+    protected CastSafeKind isTypeCastSafe(
+            AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
         if (castType.getKind().isPrimitive()) {
-            return true;
+            return CastSafeKind.SAFE;
         }
         return super.isTypeCastSafe(castType, exprType);
     }

checker/src/main/java/org/checkerframework/checker/mustcall/MustCallVisitor.java

@@ -366,9 +366,10 @@ private boolean noMustCallObligation(AnnotatedTypeMirror atm) {
     }
 
     @Override
-    protected boolean isTypeCastSafe(AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
+    protected CastSafeKind isTypeCastSafe(
+            AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
         if (noMustCallObligation(castType) || noMustCallObligation(exprType)) {
-            return true;
+            return CastSafeKind.SAFE;
         }
 
         return super.isTypeCastSafe(castType, exprType);

checker/src/main/java/org/checkerframework/checker/signedness/SignednessVisitor.java

@@ -384,10 +384,11 @@ public Void visitCompoundAssignment(CompoundAssignmentTree node, Void p) {
     }
 
     @Override
-    protected boolean isTypeCastSafe(AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
+    protected CastSafeKind isTypeCastSafe(
+            AnnotatedTypeMirror castType, AnnotatedTypeMirror exprType) {
         if (!atypeFactory.maybeIntegral(castType)) {
             // If the cast is not a number or a char, then it is legal.
-            return true;
+            return CastSafeKind.SAFE;
         }
         return super.isTypeCastSafe(castType, exprType);
     }

checker/tests/lock/ChapterExamples.java

@@ -318,7 +318,7 @@ void someMethod() {
         o2 = o1; // {"lock"} and {} are not identical sets.
     }
 
-    @SuppressWarnings("lock:cast.unsafe")
+    @SuppressWarnings("lock:cast.incompatible")
     void someMethod2() {
         // A cast can be used if the user knows it is safe to do so.
         // However, the @SuppressWarnings must be added.
@@ -564,7 +564,7 @@ public boolean compare(T[] a1, T[] a2) {
 
     private static final Object NULL_KEY = new Object();
     // A guardsatisfied.location.disallowed error is issued for the cast.
-    @SuppressWarnings({"cast.unsafe", "guardsatisfied.location.disallowed"})
+    @SuppressWarnings({"cast.incompatible", "guardsatisfied.location.disallowed"})
     private static @GuardSatisfied(1) Object maskNull(@GuardSatisfied(1) Object key) {
         return (key == null ? (@GuardSatisfied(1) Object) NULL_KEY : key);
     }

checker/tests/lock/Strings.java

@@ -13,7 +13,9 @@ void StringIsGBnothing(
             @GuardSatisfied Object o3,
             @GuardedByBottom Object o4) {
         String s1 = (String) o1;
+        // :: error: (cast.incompatible)
         String s2 = (String) o2;
+        // :: error: (cast.incompatible)
         String s3 = (String) o3;
         String s4 = (String) o4; // OK
     }

checker/tests/signedness/CharCast.java

@@ -8,13 +8,13 @@ void m(@SignedPositive int i) {
 
     void m1(short s) {
         int x = s;
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         char c = (char) x;
     }
 
     void m2(int i) {
         int x = (short) i;
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         char c = (char) x;
     }
 

checker/tests/signedness/CharToFloat.java

@@ -2,7 +2,9 @@
 
 public class CharToFloat {
     void castCharacter(Object o) {
+        // :: error: (cast.incompatible)
         floatParameter((Character) o);
+        // :: error: (cast.incompatible)
         doubleParameter((Character) o);
     }
 

checker/tests/signedness/PrimitiveCasts.java

@@ -3,7 +3,7 @@
 public class PrimitiveCasts {
 
     void shortToChar1(short s) {
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         char c = (char) s;
     }
 

checker/tests/signedness/WideningConversion.java

@@ -74,19 +74,19 @@ void plus() {
 
         char c;
         c = (char) (c1 + c2);
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         c = (char) (c1 + i2);
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         c = (char) (i1 + c2);
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         c = (char) (i1 + i2);
 
         c = (char) (c1 + c2);
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         c = (char) (c1 + si2);
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         c = (char) (si1 + c2);
-        // :: warning: (cast.unsafe)
+        // :: error: (cast.incompatible)
         c = (char) (si1 + si2);
 
         c = (char) (c1 + c2);