From 2ecb7537676e9bb6d9c104a8998c12f9e89a9ab3 Mon Sep 17 00:00:00 2001
From: Paul Dingemans <paul-dingemans@users.noreply.github.com>
Date: Tue, 25 Jun 2024 17:09:06 +0200
Subject: [PATCH] Fix false positive when anonymous function is used as value
 argument (#2718)

Closes #2694
---
 .../rules/BlankLineBeforeDeclarationRule.kt        |  7 +++++++
 .../rules/BlankLineBeforeDeclarationRuleTest.kt    | 14 ++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt
index 932c980720..53365e5b2f 100644
--- a/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt
+++ b/ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRule.kt
@@ -14,6 +14,7 @@ import com.pinterest.ktlint.rule.engine.core.api.ElementType.OBJECT_LITERAL
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.PROPERTY
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.PROPERTY_ACCESSOR
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.RETURN_KEYWORD
+import com.pinterest.ktlint.rule.engine.core.api.ElementType.VALUE_ARGUMENT
 import com.pinterest.ktlint.rule.engine.core.api.ElementType.WHEN
 import com.pinterest.ktlint.rule.engine.core.api.Rule
 import com.pinterest.ktlint.rule.engine.core.api.RuleId
@@ -132,6 +133,12 @@ public class BlankLineBeforeDeclarationRule :
             return
         }
 
+        if (node.elementType == FUN && node.treeParent.elementType == VALUE_ARGUMENT) {
+            // Allow:
+            //   val foo1 = foo2(fun() = 42)
+            return
+        }
+
         if (node.elementType == OBJECT_DECLARATION && node.treeParent.elementType == OBJECT_LITERAL) {
             // Allow:
             //   fun foo() =
diff --git a/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRuleTest.kt b/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRuleTest.kt
index e85a1a9094..236922089a 100644
--- a/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRuleTest.kt
+++ b/ktlint-ruleset-standard/src/test/kotlin/com/pinterest/ktlint/ruleset/standard/rules/BlankLineBeforeDeclarationRuleTest.kt
@@ -506,4 +506,18 @@ class BlankLineBeforeDeclarationRuleTest {
             """.trimIndent()
         blankLineBeforeDeclarationRuleAssertThat(code).hasNoLintViolations()
     }
+
+    @Test
+    fun `Issue 2694 - Given a call expression with an anonymous function as argument`() {
+        val code =
+            """
+            val foo1 =
+                foo(
+                    fun() = 42,
+                )
+
+            val foo2 = foo(fun() = 42)
+            """.trimIndent()
+        blankLineBeforeDeclarationRuleAssertThat(code).hasNoLintViolations()
+    }
 }