QualifierWithTypeUse
Injection frameworks currently don't understand Qualifiers in TYPE_PARAMETER or TYPE_USE contexts.

Category
Severity
WARNING
Maturity

The problem

Allowing a qualifier annotation in TYPE_PARAMETER or TYPE_USE contexts allows end users to write code like:

@Inject Foo(List<@MyAnnotation String> strings)

Guice, Dagger, and other dependency injection frameworks don’t currently see type annotations in this context, so the above code is equivalent to:

@Inject Foo(List<String> strings)

Suppression

Suppress false positives by adding the suppression annotation @SuppressWarnings("QualifierWithTypeUse") to the enclosing element.


Positive examples

QualifierWithTypeUsePositiveCases.java

/*
* Copyright 2016 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/


package com.google.errorprone.bugpatterns.inject.testdata;

import com.google.inject.BindingAnnotation;
import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
import javax.inject.Qualifier;

/** Tests for {@code QualifierWithTypeUse} */
public class QualifierWithTypeUsePositiveCases {

@Qualifier
// BUG: Diagnostic contains: @Target({CONSTRUCTOR})
@Target({ElementType.TYPE_USE, ElementType.CONSTRUCTOR})
@interface Qualifier1 {}

@Qualifier
// BUG: Diagnostic contains: remove
@Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
@interface Qualifier2 {}

@BindingAnnotation
// BUG: Diagnostic contains: @Target({FIELD})
@Target({ElementType.FIELD, ElementType.TYPE_USE})
@interface BindingAnnotation1 {}

@BindingAnnotation
// BUG: Diagnostic contains: remove
@Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
@interface BindingAnnotation2 {}

@BindingAnnotation
// BUG: Diagnostic contains: remove
@Target(ElementType.TYPE_USE)
@interface BindingAnnotation3 {}
}

Negative examples

QualifierWithTypeUseNegativeCases.java

/*
* Copyright 2016 Google Inc. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/


package com.google.errorprone.bugpatterns.inject.testdata;

import java.lang.annotation.ElementType;
import java.lang.annotation.Target;
import javax.inject.Qualifier;

/** Tests for {@code QualifierWithTypeUse} */
public class QualifierWithTypeUseNegativeCases {

@Qualifier
@Target({ElementType.CONSTRUCTOR})
@interface Qualifier1 {}

@Target({ElementType.TYPE_USE, ElementType.TYPE_PARAMETER})
@interface NotAQualifier {}
}