[standard:function-literal] Lambda arrow is removed too aggressively, produces non-compiling code

[mateuszkwiecinski]

Probably related to #2331

Expected Behavior

I expect the code compile after ktlint reformats the file

Observed Behavior

Formatted file contains code that doesn't compile

Steps to Reproduce

1. Run format on the following code:

fun repro(foo: Foo) {
    foo.onClick = if (Math.random() > 0.5) { -> } else null
}

class Foo(var onClick: (() -> Unit)?)

2. The lambda is removed

3. Compilation fails with Type mismatch: inferred type is Unit but (() -> Unit)? was expected

The alternative syntax would be:

foo.onClick = if (Math.random() > 0.5) {
    { }
} else {
    null
}

but it doesn't fit in a single line, so it may not be preferred in some cases

Your Environment

• Version of ktlint used: 1.1.0
• Relevant parts of the .editorconfig settings

ktlint_code_style = intellij_idea
ktlint_experimental = enabled

(I believe this should be enough)

• Name and version (or code for custom task) of integration used (Gradle plugin, Maven plugin, command line, custom Gradle task):
• Version of Gradle used (if applicable):
• Operating System and version:

[paul-dingemans]

Tnx for reporting. the one liner seems to have more problems from Ktlint's perspective, but autocorrect should never resulted in compilation errors.