Introduce @NullMarked aliasing

checker/src/main/java/org/checkerframework/checker/nullness/NullnessNoInitAnnotatedTypeFactory.java

@@ -32,6 +32,7 @@
 import org.checkerframework.dataflow.expression.ThisReference;
 import org.checkerframework.dataflow.util.NodeUtils;
 import org.checkerframework.framework.flow.CFAbstractAnalysis;
+import org.checkerframework.framework.qual.AnnotatedFor;
 import org.checkerframework.framework.qual.DefaultQualifier;
 import org.checkerframework.framework.qual.TypeUseLocation;
 import org.checkerframework.framework.type.AnnotatedTypeFactory;
@@ -416,6 +417,15 @@ public NullnessNoInitAnnotatedTypeFactory(BaseTypeChecker checker) {
                     "org.jspecify.nullness.NullMarked",
                     DefaultQualifier.class.getCanonicalName(),
                     nullMarkedDefaultQual);
+
+            AnnotationMirror annotatedForNullness =
+                    new AnnotationBuilder(processingEnv, AnnotatedFor.class)
+                            .setValue("value", new String[] {"nullness"})
+                            .build();
+            addAliasedDeclAnnotation(
+                    "org.jspecify.annotations.NullMarked",
+                    AnnotatedFor.class.getCanonicalName(),
+                    annotatedForNullness);
         }
 
         boolean permitClearProperty =

checker/src/test/java/org/checkerframework/checker/test/junit/NullnessNullMarkedTest.java

@@ -17,7 +17,12 @@ public class NullnessNullMarkedTest extends CheckerFrameworkPerDirectoryTest {
      * @param testFiles the files containing test code, which will be type-checked
      */
     public NullnessNullMarkedTest(List<File> testFiles) {
-        super(testFiles, org.checkerframework.checker.nullness.NullnessChecker.class, "nullness");
+        super(
+                testFiles,
+                org.checkerframework.checker.nullness.NullnessChecker.class,
+                "nullness",
+                // TODO: Replace this `-AonlyAnnotatedFor` flag after EISOP#1290 is merged.
+                "-AuseConservativeDefaultsForUncheckedCode=source");
     }
 
     @Parameters

checker/tests/nullness-nullmarked/NullMarkedSuppressError.java

@@ -0,0 +1,11 @@
+public class NullMarkedSuppressError {
+    @org.jspecify.annotations.NullMarked
+    class A {
+        // :: error: (assignment.type.incompatible)
+        Object o = null;
+    }
+
+    class B {
+        Object o = null;
+    }
+}

framework/src/main/java/org/checkerframework/common/basetype/BaseTypeChecker.java

@@ -4,6 +4,7 @@
 import org.checkerframework.checker.nullness.qual.Nullable;
 import org.checkerframework.checker.signature.qual.ClassGetName;
 import org.checkerframework.dataflow.cfg.visualize.CFGVisualizer;
+import org.checkerframework.framework.qual.AnnotatedFor;
 import org.checkerframework.framework.qual.SubtypeOf;
 import org.checkerframework.framework.source.SourceChecker;
 import org.checkerframework.framework.type.AnnotatedTypeFactory;
@@ -25,6 +26,7 @@
 import java.util.Set;
 
 import javax.lang.model.element.AnnotationMirror;
+import javax.lang.model.element.Element;
 
 /**
  * An abstract {@link SourceChecker} that provides a simple {@link
@@ -313,4 +315,31 @@ public BaseTypeChecker getUltimateParentChecker() {
                     causeMessage);
         }
     }
+
+    /**
+     * This method is almost similar to {@link
+     * org.checkerframework.framework.util.defaults.QualifierDefaults#isElementAnnotatedForThisChecker(Element)}.
+     * except for early return if element is null, the conservative default for "source" is not used
+     * and do not recursively check enclosing elements because the logic is implemented at call
+     * sites.
+     *
+     * @param elt the source code element to check, or null
+     * @return true if the element is annotated for this checker or an upstream checker
+     */
+    @Override
+    protected boolean isAnnotatedForThisCheckerOrUpstreamChecker(@Nullable Element elt) {
+        if (elt == null || !useConservativeDefault("source")) {
+            return false;
+        }
+
+        boolean elementAnnotatedForThisChecker = false;
+        AnnotationMirror annotatedFor = getTypeFactory().getDeclAnnotation(elt, AnnotatedFor.class);
+
+        if (annotatedFor != null) {
+            elementAnnotatedForThisChecker =
+                    getTypeFactory().doesAnnotatedForApplyToThisChecker(annotatedFor);
+        }
+
+        return elementAnnotatedForThisChecker;
+    }
 }

framework/src/main/java/org/checkerframework/framework/source/SourceChecker.java

@@ -2984,7 +2984,7 @@ protected boolean messageKeyMatches(
      * @param elt the source code element to check, or null
      * @return true if the element is annotated for this checker or an upstream checker
      */
-    private boolean isAnnotatedForThisCheckerOrUpstreamChecker(@Nullable Element elt) {
+    protected boolean isAnnotatedForThisCheckerOrUpstreamChecker(@Nullable Element elt) {
         if (elt == null || !useConservativeDefault("source")) {
             return false;
         }