From ae8a6e1d1ec113b25667e9a1ac13ce020dc12fe8 Mon Sep 17 00:00:00 2001
From: Suzanne Millstein <smillst@cs.washington.edu>
Date: Tue, 12 Dec 2023 20:51:42 -0800
Subject: [PATCH] Add support for OptionalDouble, OptionalInt, OptionalLong

Co-authored-by: Michael Ernst <mernst@cs.washington.edu>
---
 .../checker/optional/OptionalVisitor.java     | 32 +++++++++++++++++--
 checker/tests/optional/Marks4.java            | 10 ++++++
 checker/tests/optional/OptionalBoxed.java     | 24 ++++++++++++++
 3 files changed, 63 insertions(+), 3 deletions(-)
 create mode 100644 checker/tests/optional/OptionalBoxed.java

diff --git a/checker/src/main/java/org/checkerframework/checker/optional/OptionalVisitor.java b/checker/src/main/java/org/checkerframework/checker/optional/OptionalVisitor.java
index 120dbeadaf8..b9c3f38170b 100644
--- a/checker/src/main/java/org/checkerframework/checker/optional/OptionalVisitor.java
+++ b/checker/src/main/java/org/checkerframework/checker/optional/OptionalVisitor.java
@@ -15,8 +15,11 @@
 import com.sun.source.tree.UnaryTree;
 import com.sun.source.tree.VariableTree;
 import com.sun.source.util.TreePath;
+import java.util.Arrays;
 import java.util.Collection;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import javax.annotation.processing.ProcessingEnvironment;
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.ExecutableElement;
@@ -401,6 +404,10 @@ public void handleCreationElimination(MethodInvocationTree tree) {
     }
     ExpressionTree receiver = TreeUtils.getReceiverTree(tree);
     while (true) {
+      if (receiver == null) {
+        // The receiver can be null if the receiver is the implicit "this.".
+        return;
+      }
       if (receiver.getKind() != Tree.Kind.METHOD_INVOCATION) {
         return;
       }
@@ -546,14 +553,33 @@ public Void visitDeclared(AnnotatedDeclaredType type, Tree tree) {
     }
   }
 
-  /** Return true if tm represents a subtype of Collection (other than the Null type). */
+  /**
+   * Return true if tm is a subtype of Collection (other than the Null type).
+   *
+   * @param tm a type
+   * @return true if the given type is a subtype of Collection
+   */
   private boolean isCollectionType(TypeMirror tm) {
     return tm.getKind() == TypeKind.DECLARED && types.isSubtype(tm, collectionType);
   }
 
-  /** Return true if tm represents java.util.Optional. */
+  /** The fully-qualified names of the 4 optional classes in java.util. */
+  private static final Set<String> fqOptionalTypes =
+      new HashSet<>(
+          Arrays.asList(
+              "java.util.Optional",
+              "java.util.OptionalDouble",
+              "java.util.OptionalInt",
+              "java.util.OptionalLong"));
+
+  /**
+   * Return true if tm is class Optional, OptionalDouble, OptionalInt, or OptionalLong in java.util.
+   *
+   * @param tm a type
+   * @return true if the given type is Optional, OptionalDouble, OptionalInt, or OptionalLong
+   */
   private boolean isOptionalType(TypeMirror tm) {
-    return TypesUtils.isDeclaredOfName(tm, "java.util.Optional");
+    return TypesUtils.isDeclaredOfName(tm, fqOptionalTypes);
   }
 
   /**
diff --git a/checker/tests/optional/Marks4.java b/checker/tests/optional/Marks4.java
index b89e0eb02ba..87f6eabe094 100644
--- a/checker/tests/optional/Marks4.java
+++ b/checker/tests/optional/Marks4.java
@@ -16,6 +16,16 @@ String process_bad(String s) {
     return Optional.ofNullable(s).orElseGet(this::getDefault);
   }
 
+  String process_bad2(String s) {
+    // :: warning: (introduce.eliminate)
+    return Optional.<String>empty().orElseGet(this::getDefault);
+  }
+
+  String process_bad3(String s) {
+    // :: warning: (introduce.eliminate)
+    return Optional.of(s).orElseGet(this::getDefault);
+  }
+
   String process_good(String s) {
     return (s != null) ? s : getDefault();
   }
diff --git a/checker/tests/optional/OptionalBoxed.java b/checker/tests/optional/OptionalBoxed.java
new file mode 100644
index 00000000000..766d10ff428
--- /dev/null
+++ b/checker/tests/optional/OptionalBoxed.java
@@ -0,0 +1,24 @@
+import java.util.Optional;
+import java.util.OptionalDouble;
+import java.util.OptionalInt;
+import java.util.OptionalLong;
+
+class OptionalBoxed {
+
+  // :: warning: (optional.field)
+  OptionalDouble aField;
+
+  // :: warning: (optional.parameter)
+  void m(OptionalInt aParam) {
+    // :: warning: (introduce.eliminate)
+    int x = OptionalLong.of(1L).hashCode();
+    // :: warning: (introduce.eliminate)
+    long y = OptionalLong.of(1L).orElse(2L);
+    // :: warning: (introduce.eliminate)
+    boolean b = Optional.empty().isPresent();
+    // :: warning: (introduce.eliminate)
+    OptionalDouble.empty().ifPresent(d -> {});
+    // :: warning: (introduce.eliminate)
+    boolean b4 = OptionalLong.empty().isPresent();
+  }
+}