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Follow-on fix for restoring annotation on captured type wildcards #1667

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Follow-on fix for restoring annotation on captured type wildcards #1667

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7d3d061
failing tests
msridhar Jul 31, 2026
13f9ccb
fix
msridhar Jul 31, 2026
78d77c1
better name
msridhar Jul 31, 2026
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19 changes: 15 additions & 4 deletions nullaway/src/main/java/com/uber/nullaway/generics/TypeSubstitutionUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -360,17 +360,28 @@ public Type visitTypeVar(Type.TypeVar t, Type other) {
* <p>The corresponding type {@code other} may be an ordinary wildcard because javac can
* capture-convert {@code t} without capture-converting {@code other}. In such cases, the
* annotation on the bound of {@code other} should be restored to the bound of the wildcard
* corresponding to {@code t}.
* corresponding to {@code t}. Alternatively, nested capture conversion can make {@code t} a
* captured {@code extends} wildcard while the same position in {@code other} is a non-wildcard
* type. In that case, annotations from {@code other} must be restored to the backing wildcard's
* upper bound, since wildcard-aware checks use that bound rather than annotations directly on
* the captured type.
*/
@Override
public Type visitCapturedType(Type.CapturedType t, Type other) {
Type updated = updateDirectNullabilityAnnotationsForType(t, other);
Type.WildcardType otherWildcard = GenericsUtils.asWildcard(other);
if (otherWildcard == null) {
Type.WildcardType updatedWildcard;
if (otherWildcard != null) {
updatedWildcard = (Type.WildcardType) t.wildcard.accept(this, otherWildcard);
} else if (t.wildcard.kind == BoundKind.EXTENDS) {
Type updatedBound = t.wildcard.type.accept(this, other);
if (updatedBound == t.wildcard.type) {
return updated;
}
updatedWildcard = TYPE_METADATA_BUILDER.createWildcardType(t.wildcard, updatedBound);
} else {
return updated;
}
Type.WildcardType updatedWildcard =
(Type.WildcardType) t.wildcard.accept(this, otherWildcard);
if (updatedWildcard == t.wildcard) {
return updated;
}
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39 changes: 39 additions & 0 deletions nullaway/src/test/java/com/uber/nullaway/jspecify/WildcardTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -432,6 +432,45 @@ static void test(Holder<? extends Box<@Nullable String>> holder) {
.doTest();
}

@Test
public void annotationRestoredFromUpperBoundToCapturedWildcard() {
makeHelper()
.addSourceLines(
"Test.java",
"""
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
@NullMarked
class Test {
static class Nested<T extends @Nullable Object> {
Nested<T> self() {
return this;
}
Nested<? extends @Nullable T> wildcardUpperTypeVariable() {
throw new RuntimeException();
}
}

Nested<? extends String> testDirect(Nested<? extends String> receiver) {
// BUG: Diagnostic contains: incompatible types
return receiver.wildcardUpperTypeVariable();
}

Nested<? extends String> testWithSelf(Nested<? extends String> receiver) {
// BUG: Diagnostic contains: incompatible types
return receiver.self().wildcardUpperTypeVariable();
}

Nested<? extends String> testWithVar(Nested<? extends String> receiver) {
var local = receiver;
// BUG: Diagnostic contains: incompatible types
return local.wildcardUpperTypeVariable();
}
}
""")
.doTest();
}
Comment on lines +435 to +472

@coderabbitai coderabbitai Bot Jul 31, 2026

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📐 Maintainability & Code Quality | 🟠 Major | ⚡ Quick win

Add Javadoc for this non-trivial regression test.

Proposed fix 
   `@Test`
+  /** Verifies nullable bounds are restored for captured extends wildcards across receiver paths. */
   public void wildcardCaptureRestoresConcreteAnnotatedBound() {

As per coding guidelines, “Add Javadoc to every non-trivial method, including private methods.”

📝 Committable suggestion

‼️ IMPORTANT
Carefully review the code before committing. Ensure that it accurately replaces the highlighted code, contains no missing lines, and has no issues with indentation. Thoroughly test & benchmark the code to ensure it meets the requirements.

Suggested change
@Test
public void wildcardCaptureRestoresConcreteAnnotatedBound() {
makeHelper()
.addSourceLines(
"Test.java",
"""
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
@NullMarked
class Test {
static class Nested<T extends @Nullable Object> {
Nested<T> self() {
return this;
}
Nested<? extends @Nullable T> wildcardUpperTypeVariable() {
throw new RuntimeException();
}
}
Nested<? extends String> testDirect(Nested<? extends String> receiver) {
// BUG: Diagnostic contains: incompatible types
return receiver.wildcardUpperTypeVariable();
}
Nested<? extends String> testWithSelf(Nested<? extends String> receiver) {
// BUG: Diagnostic contains: incompatible types
return receiver.self().wildcardUpperTypeVariable();
}
Nested<? extends String> testWithVar(Nested<? extends String> receiver) {
var local = receiver;
// BUG: Diagnostic contains: incompatible types
return local.wildcardUpperTypeVariable();
}
}
""")
.doTest();
}
`@Test`
/** Verifies nullable bounds are restored for captured extends wildcards across receiver paths. */
public void wildcardCaptureRestoresConcreteAnnotatedBound() {
makeHelper()
.addSourceLines(
"Test.java",
"""
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
`@NullMarked`
class Test {
static class Nested<T extends `@Nullable` Object> {
Nested<T> self() {
return this;
}
Nested<? extends `@Nullable` T> wildcardUpperTypeVariable() {
throw new RuntimeException();
}
}
Nested<? extends String> testDirect(Nested<? extends String> receiver) {
// BUG: Diagnostic contains: incompatible types
return receiver.wildcardUpperTypeVariable();
}
Nested<? extends String> testWithSelf(Nested<? extends String> receiver) {
// BUG: Diagnostic contains: incompatible types
return receiver.self().wildcardUpperTypeVariable();
}
Nested<? extends String> testWithVar(Nested<? extends String> receiver) {
var local = receiver;
// BUG: Diagnostic contains: incompatible types
return local.wildcardUpperTypeVariable();
}
}
""")
.doTest();
}
🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@nullaway/src/test/java/com/uber/nullaway/jspecify/WildcardTests.java` around
lines 435 - 472, Add Javadoc to the non-trivial test method
wildcardCaptureRestoresConcreteAnnotatedBound, briefly documenting the
wildcard-capture regression scenario it covers and the expected diagnostic
behavior. Leave the test implementation and assertions unchanged.

Source: Coding guidelines


@Test
public void wildcardCaptureReturnWithTypeVariableUpperBound() {
makeHelper()
Expand Down
24 changes: 23 additions & 1 deletion test-library-models/src/test/java/com/uber/nullaway/CustomLibraryModelsTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -584,14 +584,36 @@ public void nestedWildcardWithCapturedTypeVariableBound() {
import org.jspecify.annotations.*;
@NullMarked
public class Test {
NestedAnnots<? extends String> test(

NestedAnnots<? extends String> testDirect(
NestedAnnots<? extends String> receiver) {
// should reject since return type of wildcardUpperTypeVariable
// is modeled to be NestedAnnots<? extends @Nullable T>, which
// here is incompatible with the return type NestedAnnots<? extends String>
// BUG: Diagnostic contains: incompatible types
return receiver.wildcardUpperTypeVariable();
}

NestedAnnots<? extends String> testWithSelf(
NestedAnnots<? extends String> receiver) {
// should reject since return type of wildcardUpperTypeVariable
// is modeled to be NestedAnnots<? extends @Nullable T>, which
// here is incompatible with the return type NestedAnnots<? extends String>
// BUG: Diagnostic contains: incompatible types
return receiver.self().wildcardUpperTypeVariable();
}


NestedAnnots<? extends String> testWithVar(
NestedAnnots<? extends String> receiver) {
var foo = receiver;
// should reject since return type of wildcardUpperTypeVariable
// is modeled to be NestedAnnots<? extends @Nullable T>, which
// here is incompatible with the return type NestedAnnots<? extends String>
// BUG: Diagnostic contains: incompatible types
return foo.wildcardUpperTypeVariable();
}

}
""")
.doTest();
Expand Down
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