FIR Tree

Visualize Kotlin's Frontend Intermediate Representation (FIR) right in your IDE

Available at JetBrains Marketplace

This plug-in helps you to understand the way the K2 Kotlin compiler represents the code internally.

• Adjustable resolution phase (the last one, BODY_RESOLVE, is the default),
• Click on a node in the tree to select it in the editor,
• Non-visible nodes are shown in italics and slightly grayed out.

Here's the outcome for this piece of code, fully resolved.

package function.equality

import kotlinx.coroutines.*

fun increment(x: Int) = x + 1