From 110cc79ddd3b27e57875dc19b8cbcbad92ed5b47 Mon Sep 17 00:00:00 2001
From: Nikolay Lunyak <nikolay.lunyak@jetbrains.com>
Date: Wed, 14 Jun 2023 10:19:21 +0300
Subject: [PATCH] [FIR] Improve debugging of diagnostic ranges

`UNREACHABLE_CODE` is weird.
If we look into its
positioning strategy,
we'll see that this diagnostic
attempts to split the source
of its element into multiple ranges.
This is bad, because such smaller
ranges can easily overlap with other
diagnostics in such a way that
they are no longer hierarchical.
See the
`compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/3.kt` test
for an example of this behavior
(allow reporting `UNREACHABLE_CODE`
first). The problem will appear at
the condition of `case_7`.
---
 .../jetbrains/kotlin/codeMetaInfo/CodeMetaInfoRenderer.kt   | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/compiler/test-infrastructure-utils/tests/org/jetbrains/kotlin/codeMetaInfo/CodeMetaInfoRenderer.kt b/compiler/test-infrastructure-utils/tests/org/jetbrains/kotlin/codeMetaInfo/CodeMetaInfoRenderer.kt
index 4dadb21a64a..412d043c6f6 100644
--- a/compiler/test-infrastructure-utils/tests/org/jetbrains/kotlin/codeMetaInfo/CodeMetaInfoRenderer.kt
+++ b/compiler/test-infrastructure-utils/tests/org/jetbrains/kotlin/codeMetaInfo/CodeMetaInfoRenderer.kt
@@ -61,6 +61,12 @@ object CodeMetaInfoRenderer {
 
             while (current != null) {
                 val next: CodeMetaInfo? = if (iterator.hasNext()) iterator.next() else null
+                val outer = opened.lastOrNull()
+                if (outer != null) {
+                    require(current.end <= outer.end) {
+                        "The outer diagnostic ${outer.tag} at ${outer.start} ends at ${outer.end}, but the supposedly inner ${current?.tag} starting at ${current?.start} ends at ${current?.end}. Rendered so far:\n$builder"
+                    }
+                }
                 opened.push(current)
                 builder.append(current.asString())
                 when {