fix: do not replace lambda params with underscore when used as assignment target - #1117

Merged

timtebeek merged 1 commit into

openrewrite:mainfrom

darrencilia:fix/replace-unused-variables-assignment-target

May 28, 2026

darrencilia commented May 28, 2026 •

edited by moderne-meeseeks Bot

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Contributor

Problem

ReplaceUnusedVariablesWithUnderscore incorrectly renames lambda parameters to _ when they appear as LHS assignment targets, producing uncompilable code.

Fix

Added usedAsAssignmentTarget() guard following the same pattern as the existing usedInModifyingUnary() method, and wired it into renameVariableIfUnusedInContext.

Tests

Added three test cases covering:

First param as assignment target, second correctly renamed
Second param as assignment target, first correctly renamed
Single param as assignment target
Fixes ReplaceUnusedVariablesWithUnderscore incorrectly renames lambda params used as assignment targets producing uncompilable code #1116


          fix: do not replace lambda params with underscore when used as assign…

4dd38bd

…ment target

moderne-meeseeks Bot added this to OpenRewrite

moderne-meeseeks Bot assigned darrencilia

github-project-automation Bot moved this to In Progress in OpenRewrite

timtebeek approved these changes

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timtebeek left a comment

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Thanks for the immediate fix! Looks perfect.

github-project-automation Bot moved this from In Progress to Ready to Review in OpenRewrite

timtebeek merged commit 21548bd into openrewrite:main

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github-project-automation Bot moved this from Ready to Review to Done in OpenRewrite

darrencilia deleted the fix/replace-unused-variables-assignment-target branch

May 28, 2026 19:07

mergify Bot added a commit to robfrank/linklift that referenced this pull request


          chore(deps): bump org.openrewrite.recipe:rewrite-migrate-java from 3.…

b60e1b8

…34.0 to 3.36.0 [skip ci]

Bumps [org.openrewrite.recipe:rewrite-migrate-java](https://github.com/openrewrite/rewrite-migrate-java) from 3.34.0 to 3.36.0.
Release notes

*Sourced from [org.openrewrite.recipe:rewrite-migrate-java's releases](https://github.com/openrewrite/rewrite-migrate-java/releases).*

> 3.36.0
> ------
>
> What's Changed
> --------------
>
> * Move StringFormatted recipe from Java 17 upgrade to Java best practices by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1106](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1106)
> * Skip `IfElseIfConstructToSwitch` when a trailing non-`== null` binary check is present by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1109](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1109)
> * Skip `UseTextBlocks` when literal value matches its source by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1111](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1111)
> * Skip `UseMapOf` for `HashMap` subclasses like `LinkedHashMap` and `TreeMap` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1113](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1113)
> * Skip `RenameUnderscoreIdentifier` on Kotlin and Groovy sources by [`@MBoegers`](https://github.com/MBoegers) in [openrewrite/rewrite-migrate-java#1114](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1114)
> * Do not add `java.io.IO` import in `ReplaceSystemOutWithIOPrint` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1118](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1118)
> * fix: do not replace lambda params with underscore when used as assignment target by [`@darrencilia`](https://github.com/darrencilia) in [openrewrite/rewrite-migrate-java#1117](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1117)
> * Route WSS4J message.token classes to their real 2.x packages by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1122](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1122)
> * Migrate `com.sun.xml.bind.marshaller.NamespacePrefixMapper` to `org.glassfish.jaxb.runtime.marshaller.NamespacePrefixMapper` by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1121](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1121)
> * Fix `RefineSwitchCases` generating invalid guard on enum constant labels by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1124](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1124)
> * Skip unparseable Java versions in FindJavaVersion instead of reporting -1 by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1125](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1125)
>
> New Contributors
> ----------------
>
> * [`@darrencilia`](https://github.com/darrencilia) made their first contribution in [openrewrite/rewrite-migrate-java#1117](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1117)
>
> **Full Changelog**: <openrewrite/rewrite-migrate-java@v3.35.0...v3.36.0>
>
> 3.35.0
> ------
>
> What's Changed
> --------------
>
> * Add `java.io.IO` import in `ReplaceSystemOutWithIOPrint` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1093](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1093)
> * Skip `UseMapOf` when `put()` argument is a null literal by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1094](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1094)
> * Migrate JAXB XJC binding files declaring version 2.0/2.1/2.2 by [`@MBoegers`](https://github.com/MBoegers) in [openrewrite/rewrite-migrate-java#1098](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1098)
> * Preserve explicit type arguments in MigrateCollections\* recipes by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1099](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1099)
> * Route Maven through Moderne Artifactory cache to avoid HTTP 429 by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1096](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1096)
> * Load sun.internal.new[Class].jar directly to fix CI test failures by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1101](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1101)
> * Skip explicit type arguments containing wildcards in `UseVarForGenericMethodInvocations` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1102](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1102)
> * Skip `var` when target type inference widens a generic argument by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1103](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1103)
> * Skip `IfElseIfConstructToSwitch` when `instanceof` types are missing by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1095](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1095)
> * Revert inline Maven mirror (now in gh-automation#95) by [`@Jenson3210`](https://github.com/Jenson3210) in [openrewrite/rewrite-migrate-java#1104](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1104)
> * Aggregate FindJavaVersion to one row per repository by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1105](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1105)
>
> **Full Changelog**: <openrewrite/rewrite-migrate-java@v3.34.1...v3.35.0>
>
> v3.34.1
> -------
>
> What's Changed
> --------------
>
> * OpenRewrite [v8.81.6](https://github.com/openrewrite/rewrite/releases/tag/v8.81.6)
> * Refresh UpdateSdkManTest fixtures after SDKMAN CSV update by [`@steve-aom-elliott`](https://github.com/steve-aom-elliott) in [openrewrite/rewrite-migrate-java#1073](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1073)
> * Add more static analysis recipes to java-best-practices by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1075](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1075)
> * OpenRewrite recipe best practices by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1074](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1074)
> * Add jspecify hyperlink by [`@sullis`](https://github.com/sullis) in [openrewrite/rewrite-migrate-java#1076](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1076)
> * Skip `var` when reassignment relies on declared supertype by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1078](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1078)
> * Keep parentheses when renaming typed lambda parameter to underscore by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1082](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1082)
> * Document null-probing semantic differences in singleton migrations by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1081](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1081)
> * Skip main migration when referenced as static API by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1084](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1084)
> * Skip `Immutable*.copyOf` rewrite when argument is not a `Collection` by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1089](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1089)
> * Keep block body when refined switch arm contains an if statement by [`@timtebeek`](https://github.com/timtebeek) in [openrewrite/rewrite-migrate-java#1088](https://redirect.github.com/openrewrite/rewrite-migrate-java/pull/1088)

... (truncated)


Commits

* [`d4df178`](openrewrite/rewrite-migrate-java@d4df178) Skip unparseable Java versions in FindJavaVersion instead of reporting -1 ([#1](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1)...
* [`b8a298e`](openrewrite/rewrite-migrate-java@b8a298e) Fix `RefineSwitchCases` generating invalid guard on enum constant labels ([#1124](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1124))
* [`c7f400b`](openrewrite/rewrite-migrate-java@c7f400b) [Auto] SDKMAN! Java candidates as of 2026-06-01T1550
* [`fca7c7c`](openrewrite/rewrite-migrate-java@fca7c7c) Migrate `com.sun.xml.bind.marshaller.NamespacePrefixMapper` to `org.glassfish...
* [`74017b2`](openrewrite/rewrite-migrate-java@74017b2) Route WSS4J message.token classes to their real 2.x packages ([#1122](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1122))
* [`52b0808`](openrewrite/rewrite-migrate-java@52b0808) OpenRewrite recipe best practices
* [`23e5804`](openrewrite/rewrite-migrate-java@23e5804) Update Gradle wrapper 9.5.1
* [`21548bd`](openrewrite/rewrite-migrate-java@21548bd) fix: do not replace lambda params with underscore when used as assignment tar...
* [`61e7d90`](openrewrite/rewrite-migrate-java@61e7d90) Do not add `java.io.IO` import in `ReplaceSystemOutWithIOPrint` ([#1118](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1118))
* [`dec86d0`](openrewrite/rewrite-migrate-java@dec86d0) Skip `RenameUnderscoreIdentifier` on Kotlin and Groovy sources ([#1114](https://redirect.github.com/openrewrite/rewrite-migrate-java/issues/1114))
* Additional commits viewable in [compare view](openrewrite/rewrite-migrate-java@v3.34.0...v3.36.0)
  
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