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Improve support method invocations for RemoveRedundantTypeCast #711

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Merged
timtebeek merged 10 commits into from
Aug 15, 2025
Merged

Improve support method invocations for RemoveRedundantTypeCast #711

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ceaccfa
Add exact equals type check for RemoveRedundantTypeCast
jevanlingen Aug 15, 2025
ef34e2a
Apply suggestion from @github-actions[bot]
jevanlingen Aug 15, 2025
bf95151
Support child classes
jevanlingen Aug 15, 2025
1c92cfc
Keep prefix of Parentheses
jevanlingen Aug 15, 2025
f59a32f
Return statement with parentheses expression should be able to remove…
jevanlingen Aug 15, 2025
4af1a1c
Handle Kotlin case
jevanlingen Aug 15, 2025
f44f32c
Handle Kotlin case
jevanlingen Aug 15, 2025
ae58c30
Update src/test/java/org/openrewrite/staticanalysis/RemoveRedundantTy…
jevanlingen Aug 15, 2025
c853c61
Exclude Kotlin
jevanlingen Aug 15, 2025
165c589
Polish
jevanlingen Aug 15, 2025
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53 changes: 44 additions & 9 deletions src/main/java/org/openrewrite/staticanalysis/RemoveRedundantTypeCast.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@
import org.openrewrite.*;
import org.openrewrite.java.JavaVisitor;
import org.openrewrite.java.tree.*;
import org.openrewrite.staticanalysis.kotlin.KotlinFileChecker;

import java.time.Duration;
import java.util.List;
Expand All @@ -28,14 +29,16 @@

@Incubating(since = "7.23.0")
public class RemoveRedundantTypeCast extends Recipe {
private static final String REMOVE_UNNECESSARY_PARENTHESES = "removeUnnecessaryParentheses";

@Override
public String getDisplayName() {
return "Remove redundant casts";
}

@Override
public String getDescription() {
return "Removes unnecessary type casts. Does not currently check casts in lambdas, class constructors, and method invocations.";
return "Removes unnecessary type casts. Does not currently check casts in lambdas and class constructors.";
}

@Override
Expand All @@ -50,7 +53,7 @@ public Set<String> getTags() {

@Override
public TreeVisitor<?, ExecutionContext> getVisitor() {
return new JavaVisitor<ExecutionContext>() {
return Preconditions.check(Preconditions.not(new KotlinFileChecker<>()), new JavaVisitor<ExecutionContext>() {
@Override
public J visitTypeCast(J.TypeCast typeCast, ExecutionContext ctx) {
J visited = super.visitTypeCast(typeCast, ctx);
Expand All @@ -68,8 +71,14 @@ public J visitTypeCast(J.TypeCast typeCast, ExecutionContext ctx) {

J parentValue = parent.getValue();

J.TypeCast visitedTypeCast = (J.TypeCast) visited;
JavaType expressionType = visitedTypeCast.getExpression().getType();
JavaType castType = visitedTypeCast.getType();

JavaType targetType = null;
if (parentValue instanceof J.VariableDeclarations) {
if (castType.equals(expressionType)) {
targetType = castType;
} else if (parentValue instanceof J.VariableDeclarations) {
targetType = ((J.VariableDeclarations) parentValue).getVariables().get(0).getType();
} else if (parentValue instanceof MethodCall) {
MethodCall methodCall = (MethodCall) parentValue;
Expand All @@ -87,7 +96,10 @@ public J visitTypeCast(J.TypeCast typeCast, ExecutionContext ctx) {
}
}
}
} else if (parentValue instanceof J.Return && ((J.Return) parentValue).getExpression() == typeCast) {
if (TypeUtils.isAssignableTo(castType, expressionType)) {
targetType = castType;
}
} else if (parentValue instanceof J.Return && expressionIsTypeCast((J.Return) parentValue, typeCast)) {
parent = parent.dropParentUntil(is -> is instanceof J.Lambda ||
is instanceof J.MethodDeclaration ||
is instanceof J.ClassDeclaration ||
Expand All @@ -98,10 +110,6 @@ public J visitTypeCast(J.TypeCast typeCast, ExecutionContext ctx) {
}
}

J.TypeCast visitedTypeCast = (J.TypeCast) visited;
JavaType expressionType = visitedTypeCast.getExpression().getType();
JavaType castType = visitedTypeCast.getType();

if (targetType == null) {
return visitedTypeCast;
}
Expand Down Expand Up @@ -135,11 +143,24 @@ public J visitTypeCast(J.TypeCast typeCast, ExecutionContext ctx) {
if (fullyQualified != null) {
maybeRemoveImport(fullyQualified.getFullyQualifiedName());
}
Cursor directParent = getCursor().getParent();
if (directParent != null && directParent.getParent() != null && directParent.getParent().getValue() instanceof J.Parentheses) {
directParent.getParent().putMessage(REMOVE_UNNECESSARY_PARENTHESES, true);
}
return visitedTypeCast.getExpression().withPrefix(visitedTypeCast.getPrefix());
}
return visitedTypeCast;
}

@Override
public <T extends J> J visitParentheses(J.Parentheses<T> parens, ExecutionContext ctx) {
J.Parentheses<T> parentheses = (J.Parentheses<T>) super.visitParentheses(parens, ctx);
if (getCursor().getMessage(REMOVE_UNNECESSARY_PARENTHESES, false)) {
return parentheses.getTree().withPrefix(parentheses.getPrefix());
}
return parentheses;
}

private JavaType getParameterType(JavaType.Method method, int arg) {
List<JavaType> parameterTypes = method.getParameterTypes();
if (parameterTypes.size() > arg) {
Expand All @@ -149,6 +170,20 @@ private JavaType getParameterType(JavaType.Method method, int arg) {
JavaType type = parameterTypes.get(parameterTypes.size() - 1);
return type instanceof JavaType.Array ? ((JavaType.Array) type).getElemType() : type;
}
};

private boolean expressionIsTypeCast(J.Return return_, J.TypeCast typeCast) {
if (return_.getExpression() instanceof J.Parentheses<?>) {
return expressionIsTypeCast((J.Parentheses<?>) return_.getExpression(), typeCast);
}
return return_.getExpression() == typeCast;
}

private boolean expressionIsTypeCast(J.Parentheses<?> parentheses, J.TypeCast typeCast) {
if (parentheses.getTree() instanceof J.Parentheses) {
return expressionIsTypeCast((J.Parentheses<?> ) parentheses.getTree(), typeCast);
}
return parentheses.getTree() == typeCast;
}
});
}
}
57 changes: 56 additions & 1 deletion src/test/java/org/openrewrite/staticanalysis/RemoveRedundantTypeCastTest.java
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Original file line number Diff line number Diff line change
Expand Up @@ -471,7 +471,7 @@ void removeImport() {

class Test {
List method(List list) {
return (ArrayList) list;
return ((ArrayList) list);
}
}
""",
Expand Down Expand Up @@ -556,4 +556,59 @@ public Bar baz() {
)
);
}

@Test
void chainedMethods() {
// language=java
rewriteRun(
java(
"""
class Bar {
String getName() {
return "The bar";
}
}
class ChildBar extends Bar {}
"""
),
java(
"""
class Foo {
public void getBarName() {
String.format(((Bar) getBar()).getName());
((Bar) getBar()).getName();
((Bar) getChildBar()).getName();
((((Bar) getBar()))).getName();
}

private Bar getBar() {
return new Bar();
}

private ChildBar getChildBar() {
return new ChildBar();
}
}
""",
"""
class Foo {
public void getBarName() {
String.format(getBar().getName());
getBar().getName();
getChildBar().getName();
((getBar())).getName();
}

private Bar getBar() {
return new Bar();
}

private ChildBar getChildBar() {
return new ChildBar();
}
}
"""
)
);
}
}