BindingReceiverParameter.md.html

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(#) @Binds/@Provides functions cannot be extensions

!!! ERROR: @Binds/@Provides functions cannot be extensions
   This is an error.

Id
:   `BindingReceiverParameter`
Summary
:   @Binds/@Provides functions cannot be extensions
Severity
:   Error
Category
:   Correctness
Platform
:   Any
Vendor
:   slack
Identifier
:   slack-lint
Contact
:   https://github.com/slackhq/slack-lints
Feedback
:   https://github.com/slackhq/slack-lints
Min
:   Lint 8.0 and 8.1
Compiled
:   Lint 8.0 and 8.1
Artifact
:   [com.slack.lint:slack-lint-checks](com_slack_lint_slack-lint-checks.md.html)

Affects
:   Kotlin and Java files and test sources
Editing
:   This check runs on the fly in the IDE editor
Implementation
:   [Source Code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/main/java/slack/lint/DaggerIssuesDetector.kt)
Tests
:   [Source Code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/test/java/slack/lint/DaggerIssuesDetectorTest.kt)
Copyright Year
:   2021

@Binds/@Provides functions cannot be extension functions. Move the
receiver type to a parameter via IDE inspection (option+enter and
convert to parameter).

(##) Example

Here is an example of lint warnings produced by this check:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text
src/foo/MyQualifier.kt:12:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun Int.bind(): Number
             ---
src/foo/MyQualifier.kt:13:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun Long.bind(): Number
             ----
src/foo/MyQualifier.kt:14:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun Double.bind(): Number
             ------
src/foo/MyQualifier.kt:15:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun Float.bind(): Number
             -----
src/foo/MyQualifier.kt:16:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun Short.bind(): Number
             -----
src/foo/MyQualifier.kt:17:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun Byte.bind(): Number
             ----
src/foo/MyQualifier.kt:18:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun Char.bind(): Comparable&lt;Char&gt;
             ----
src/foo/MyQualifier.kt:19:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun String.bind(): Comparable&lt;String&gt;
             ------
src/foo/MyQualifier.kt:20:Error: @Binds/@Provides functions cannot be
extensions [BindingReceiverParameter]
  @Binds fun @receiver:MyQualifier Boolean.bind(): Comparable&lt;Boolean&gt;
                                   -------
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Here is the source file referenced above:

`src/foo/MyQualifier.kt`:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~kotlin linenumbers
package foo
import javax.inject.Qualifier
import dagger.Binds
import dagger.Provides
import dagger.Module

@Qualifier
annotation class MyQualifier

@Module
interface MyModule {
  @Binds fun Int.bind(): Number
  @Binds fun Long.bind(): Number
  @Binds fun Double.bind(): Number
  @Binds fun Float.bind(): Number
  @Binds fun Short.bind(): Number
  @Binds fun Byte.bind(): Number
  @Binds fun Char.bind(): Comparable<Char>
  @Binds fun String.bind(): Comparable<String>
  @Binds fun @receiver:MyQualifier Boolean.bind(): Comparable<Boolean>
}

@Module
interface MyModule2 {
  @Provides fun Int.bind(): Number = this@bind
  @Provides fun Long.bind(): Number = this@bind
  @Provides fun Double.bind(): Number = this@bind
  @Provides fun Float.bind(): Number = this@bind
  @Provides fun Short.bind(): Number = this@bind
  @Provides fun Byte.bind(): Number = this@bind
  @Provides fun Char.bind(): Comparable<Char> = this@bind
  @Provides fun String.bind(): Comparable<String> = this@bind
  @Provides fun @receiver:MyQualifier Boolean.bind(): Comparable<Boolean> = this@bind
}
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can also visit the
[source code](https://github.com/slackhq/slack-lints/tree/main/slack-lint-checks/src/test/java/slack/lint/DaggerIssuesDetectorTest.kt)
for the unit tests for this check to see additional scenarios.

The above example was automatically extracted from the first unit test
found for this lint check, `DaggerIssuesDetector.bindings cannot be extension functions`.
To report a problem with this extracted sample, visit
https://github.com/slackhq/slack-lints.

(##) Including

!!!
   This is not a built-in check. To include it, add the below dependency
   to your project. This lint check is included in the lint documentation,
   but the Android team may or may not agree with its recommendations.

```
// build.gradle.kts
lintChecks("com.slack.lint:slack-lint-checks:0.7.4")

// build.gradle
lintChecks 'com.slack.lint:slack-lint-checks:0.7.4'

// build.gradle.kts with version catalogs:
lintChecks(libs.slack.lint.checks)

# libs.versions.toml
[versions]
slack-lint-checks = "0.7.4"
[libraries]
slack-lint-checks = {
    module = "com.slack.lint:slack-lint-checks",
    version.ref = "slack-lint-checks"
}
```

0.7.4 is the version this documentation was generated from;
there may be newer versions available.

[Additional details about com.slack.lint:slack-lint-checks](com_slack_lint_slack-lint-checks.md.html).
(##) Suppressing

You can suppress false positives using one of the following mechanisms:

* Using a suppression annotation like this on the enclosing
  element:

  ```kt
  // Kotlin
  @Suppress("BindingReceiverParameter")
  fun method() {
     problematicStatement()
  }
  ```

  or

  ```java
  // Java
  @SuppressWarnings("BindingReceiverParameter")
  void method() {
     problematicStatement();
  }
  ```

* Using a suppression comment like this on the line above:

  ```kt
  //noinspection BindingReceiverParameter
  problematicStatement()
  ```

* Using a special `lint.xml` file in the source tree which turns off
  the check in that folder and any sub folder. A simple file might look
  like this:
  ```xml
  &lt;?xml version="1.0" encoding="UTF-8"?&gt;
  &lt;lint&gt;
      &lt;issue id="BindingReceiverParameter" severity="ignore" /&gt;
  &lt;/lint&gt;
  ```
  Instead of `ignore` you can also change the severity here, for
  example from `error` to `warning`. You can find additional
  documentation on how to filter issues by path, regular expression and
  so on
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html).

* In Gradle projects, using the DSL syntax to configure lint. For
  example, you can use something like
  ```gradle
  lintOptions {
      disable 'BindingReceiverParameter'
  }
  ```
  In Android projects this should be nested inside an `android { }`
  block.

* For manual invocations of `lint`, using the `--ignore` flag:
  ```
  $ lint --ignore BindingReceiverParameter ...`
  ```

* Last, but not least, using baselines, as discussed
  [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).

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