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fix: Improved type checking for UnnecessaryLambdaEnclosingParameters #910

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fix: Improved type checking for UnnecessaryLambdaEnclosingParameters #910

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fix: Improved type checking for UnnecessaryLambdaEnclosingParameters
gbq6 Sep 28, 2025
24f869e
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gbq6 Sep 28, 2025
96ff450
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gbq6 Sep 29, 2025
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29 changes: 12 additions & 17 deletions ...olven/cleanthat/engine/java/refactorer/mutators/UnnecessaryLambdaEnclosingParameters.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
/*
* Copyright 2023 Benoit Lacelle - SOLVEN
* Copyright 2023-2025 Benoit Lacelle - SOLVEN
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
Expand All @@ -17,19 +17,20 @@

import java.util.Set;

import com.github.javaparser.ast.expr.Expression;
import com.github.javaparser.ast.expr.LambdaExpr;
import com.google.common.collect.ImmutableSet;

import eu.solven.cleanthat.engine.java.IJdkVersionConstants;
import eu.solven.cleanthat.engine.java.refactorer.AJavaparserNodeMutator;
import eu.solven.cleanthat.engine.java.refactorer.AJavaparserExprMutator;
import eu.solven.cleanthat.engine.java.refactorer.NodeAndSymbolSolver;

/**
* Turns '.stream((s) -> s.subString(0, 2))' into '.stream(s -> s.subString(0, 2))'
*
* @author Benoit Lacelle
*/
public class UnnecessaryLambdaEnclosingParameters extends AJavaparserNodeMutator {
public class UnnecessaryLambdaEnclosingParameters extends AJavaparserExprMutator {

@Override
public String minimalJavaVersion() {
Expand All @@ -48,24 +49,18 @@ public boolean isDraft() {
}

@Override
protected boolean processNotRecursively(NodeAndSymbolSolver<?> node) {
protected boolean processExpression(NodeAndSymbolSolver<Expression> node) {
if (!(node.getNode() instanceof LambdaExpr)) {
return false;
}

var lambdaExpr = (LambdaExpr) node.getNode();
if (lambdaExpr.getParameters().size() != 1 || !lambdaExpr.isEnclosingParameters()) {
return false;
}

var param = lambdaExpr.getParameters().get(0);
if (param.getType() != null) {
return false;
}

var newLambdaExpr = lambdaExpr.clone();
newLambdaExpr.setEnclosingParameters(false);
return tryReplace(lambdaExpr, newLambdaExpr);
if (lambdaExpr.getParameters().size() != 1 || lambdaExpr.isExplicitlyTyped()) {
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@blacelle blacelle Sep 28, 2025

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Could you craft a unit-test catching what's brought by this PR?

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@gbq6 gbq6 Sep 28, 2025 •
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Actually any test with @CompareMethods would have revealed this issue, but as the the JavaParser seems to ignore setEnclosingParameters(false) these tests are ignored. I'll add a comment regarding that if you don't mind though.

Edit: 24f869e

return false;
}

}
var newLambdaExpr = lambdaExpr.clone();
newLambdaExpr.setEnclosingParameters(false);
return tryReplace(lambdaExpr, newLambdaExpr);
}
}
2 changes: 1 addition & 1 deletion ...java/refactorer/cases/do_not_format_me/TestUnnecessaryLambdaEnclosingParametersCases.java
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Expand Up @@ -25,7 +25,7 @@ public Runnable pre() {
}
}

@Ignore("TODO")
@Ignore("JavaParser seems to ignore `setEnclosingParameters(false)`")
@CompareMethods
public static class CaseFunction {
public Function<Integer, Integer> pre() {
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