Cursive crash in clojure.test diff can make failing assertions appear to pass

[cmf]

A user reports that certain failing clojure.test assertions involving Java objects can crash Cursive's diff formatting, after which the test appears to pass. This is especially problematic because a real assertion failure is hidden by the crash.

Reproducer

foo/Foo.java:

package foo;

import java.util.function.Predicate;

public interface Foo {
    Predicate<String> BAR = s -> true;
}

mytest.clj:

(ns mytest
  (:require [clojure.test :as t])
  (:import (foo Foo)))

(t/deftest crash
  (t/is (= {:k Foo/BAR} {:k nil})))

Actual result

Cursive crashes 100% of the time when running the test, and the test then appears to pass even though the assertion should fail.

Reported stack trace excerpt:

Caused by: java.lang.NullPointerException: null cannot be cast to non-null type com.intellij.psi.PsiElement
    at cursive.diff.DiffKt.formatMap(diff.kt:65)
    at cursive.diff.DiffKt.toFormat(diff.kt:94)
    at cursive.diff.DiffKt.toFormat$lambda$0(diff.kt:99)
    ...

Expected result

The assertion failure should be reported as a failed test, and Cursive should not crash while formatting/displaying the diff.

Notes

The user has submitted crash reports and raised this because the apparent passing result is deceptive.

[cmf]

Fix released in 2026.2-eap1 on 2026-05-22.