LambdaFunctionalInterface crash with IllegalArgumentException when processing an enum constructor taking a lambda

[dododge]

Tested with error-prone 2.16 and openjdk 19.0.1 but it happens with other/earlier versions as well.

The LambdaFunctionalInterface pattern crashes with an IllegalArgumentException when trying to check an enum that has a lambda or method reference parameter. Example:

package org.example;

import java.util.function.Function;

public enum EnumWithLambda
{
    VALUE(String::length);

    private final Function<String, Integer> func;

    EnumWithLambda(Function<String, Integer> func) {
        this.func = func;
    }

    public int apply(String str) {
        return func.apply(str);
    }
}

[ERROR]      error-prone version: 2.16
[ERROR]      BugPattern: LambdaFunctionalInterface
[ERROR]      Stack Trace:
[ERROR]      java.lang.IllegalArgumentException: No enclosing class found
[ERROR]   	at com.google.errorprone.bugpatterns.LambdaFunctionalInterface.lambda$getTopLevelClassTree$8(LambdaFunctionalInterface.java:238)
[ERROR]   	at java.base/java.util.Optional.orElseThrow(Optional.java:403)
[ERROR]   	at com.google.errorprone.bugpatterns.LambdaFunctionalInterface.getTopLevelClassTree(LambdaFunctionalInterface.java:238)
[ERROR]   	at com.google.errorprone.bugpatterns.LambdaFunctionalInterface.methodCallsMeetConditions(LambdaFunctionalInterface.java:210)
[ERROR]   	at com.google.errorprone.bugpatterns.LambdaFunctionalInterface.matchMethod(LambdaFunctionalInterface.java:164)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScanner.processMatchers(ErrorProneScanner.java:449)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScanner.visitMethod(ErrorProneScanner.java:739)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScanner.visitMethod(ErrorProneScanner.java:150)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:944)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:92)
[ERROR]   	at com.google.errorprone.scanner.Scanner.scan(Scanner.java:74)
[ERROR]   	at com.google.errorprone.scanner.Scanner.scan(Scanner.java:48)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:96)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreeScanner.scan(TreeScanner.java:111)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:119)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreeScanner.visitClass(TreeScanner.java:203)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScanner.visitClass(ErrorProneScanner.java:548)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScanner.visitClass(ErrorProneScanner.java:150)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:851)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:92)
[ERROR]   	at com.google.errorprone.scanner.Scanner.scan(Scanner.java:74)
[ERROR]   	at com.google.errorprone.scanner.Scanner.scan(Scanner.java:48)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreeScanner.scan(TreeScanner.java:111)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:119)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreeScanner.visitCompilationUnit(TreeScanner.java:152)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:560)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScanner.visitCompilationUnit(ErrorProneScanner.java:150)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCCompilationUnit.accept(JCTree.java:619)
[ERROR]   	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:66)
[ERROR]   	at com.google.errorprone.scanner.Scanner.scan(Scanner.java:58)
[ERROR]   	at com.google.errorprone.scanner.ErrorProneScannerTransformer.apply(ErrorProneScannerTransformer.java:43)
[ERROR]   	at com.google.errorprone.ErrorProneAnalyzer.finished(ErrorProneAnalyzer.java:152)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.api.MultiTaskListener.finished(MultiTaskListener.java:132)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1394)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1341)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:933)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:317)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:176)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:64)
[ERROR]   	at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:50)

[graememorgan]

Thanks for the report with a repro; I've sent a fix internally, should be in the next release.