Repository navigation

Skip `var` when reassignment relies on declared supertype - #1078

Merged

timtebeek merged 2 commits into

mainfrom

May 4, 2026

timtebeek commented May 4, 2026 •

edited by moderne-meeseeks Bot

Loading

Member

Summary

Detect reassignments to a variable within its enclosing method via a new DeclarationCheck.isReassigned helper.
In UseVarForGenericsConstructors and UseVarForGenericMethodInvocations, skip the transformation when the declared type differs from the initializer's concrete type and the variable is later reassigned, since var would narrow the inferred type and break those reassignments.
Adds a regression test mirroring the Set<ConstantFact> currentFacts = new HashSet<>(...) case from the issue.
Fixes Issue discovered on src/test/java/org/openrewrite/analysis/dataflow/ForwardDataFlowAnalysisTest.java with UseVarForGenericsConstructors #1077

Test plan

./gradlew test --tests "org.openrewrite.java.migrate.lang.var.*"


          Skip var when reassignment relies on declared supertype

b58ac91

When a generic variable is declared as a supertype but initialized with a
concrete subtype constructor or method, switching to `var` narrows the
inferred type and breaks later reassignments. Detect reassignment within
the enclosing method and skip the transformation in that case.

Fixes #1077

moderne-meeseeks Bot added this to OpenRewrite

moderne-meeseeks Bot assigned timtebeek

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


          Fix flaky JohnzonJavaxtoJakartaTest and use .reduce in var helper

4f86913

The test's `2.1.\d+` regex matched `<johnzon.version>2.1.0</johnzon.version>`
before reaching the jakarta.json-api dependency, so when jakarta.json-api
was released as 2.1.3 the expected/actual diverged. Anchor the regex to
the jakarta.json-api artifact.

Also consolidate the `isReassigned` visitor to use `.reduce(...)` directly,
matching the existing idiom in NullCheck and other recipes.

timtebeek merged commit 4ea1191 into main

1 check passed

timtebeek deleted the tim/issue-1077 branch

May 4, 2026 09:43

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

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)
  
[![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility\_score?dependency-name=org.openrewrite.recipe:rewrite-migrate-java&package-manager=maven&previous-version=3.34.0&new-version=3.36.0)](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores)
Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`.
[//]: # (dependabot-automerge-start)
[//]: # (dependabot-automerge-end)
---
Dependabot commands and options
  
You can trigger Dependabot actions by commenting on this PR:
- `@dependabot rebase` will rebase this PR
- `@dependabot recreate` will recreate this PR, overwriting any edits that have been made to it
- `@dependabot show  ignore conditions` will show all of the ignore conditions of the specified dependency
- `@dependabot ignore this major version` will close this PR and stop Dependabot creating any more for this major version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this minor version` will close this PR and stop Dependabot creating any more for this minor version (unless you reopen the PR or upgrade to it yourself)
- `@dependabot ignore this dependency` will close this PR and stop Dependabot creating any more for this dependency (unless you reopen the PR or upgrade to it yourself)

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet