Fix crash with suggested suppressions in JSpecify mode (#1001)

We were calling the wrong overload and hence accidentally passing an
incorrect tree on which to apply a `@SuppressWarnings` annotation.

Fixes #996

Author: msridhar

nullaway/src/main/java/com/uber/nullaway/NullAway.java

@@ -498,7 +498,6 @@ public Description matchAssignment(AssignmentTree tree, VisitorState state) {
           // logic
           return errorBuilder.createErrorDescription(
               errorMessage,
-              expression,
               buildDescription(tree),
               state,
               ASTHelpers.getSymbol(tree.getVariable()));

nullaway/src/test/java/com/uber/nullaway/jspecify/SuggestedFixesTests.java

@@ -0,0 +1,53 @@
+package com.uber.nullaway.jspecify;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.uber.nullaway.NullAway;
+import java.io.IOException;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
+
+/** Tests for combining fix suggestions with JSpecify mode. */
+public class SuggestedFixesTests {
+
+  @Rule public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
+  private BugCheckerRefactoringTestHelper makeTestHelper() {
+    return BugCheckerRefactoringTestHelper.newInstance(NullAway.class, getClass())
+        .setArgs(
+            "-d",
+            temporaryFolder.getRoot().getAbsolutePath(),
+            "-processorpath",
+            SuggestedFixesTests.class.getProtectionDomain().getCodeSource().getLocation().getPath(),
+            "-XepOpt:NullAway:AnnotatedPackages=com.uber",
+            "-XepOpt:NullAway:JSpecifyMode=true",
+            "-XepOpt:NullAway:SuggestSuppressions=true");
+  }
+
+  @Test
+  public void suggestSuppressionForAssigningNullableIntoNonNullArray() throws IOException {
+    makeTestHelper()
+        .addInputLines(
+            "Test.java",
+            "package com.uber;",
+            "import org.jspecify.annotations.Nullable;",
+            "class Test {",
+            "  void test() {",
+            "    Object[] arr = new Object[1];",
+            "    arr[0] = null;",
+            "  }",
+            "}")
+        .addOutputLines(
+            "out/Test.java",
+            "package com.uber;",
+            "import org.jspecify.annotations.Nullable;",
+            "class Test {",
+            "  @SuppressWarnings(\"NullAway\")",
+            "  void test() {",
+            "    Object[] arr = new Object[1];",
+            "    arr[0] = null;",
+            "  }",
+            "}")
+        .doTest();
+  }
+}