When running format mode, the rules are first executed in parallel to…

… find linting errors. In this process,

no unused import are found because the trailing comma is not yet added to variable "bar3". Then in the next
stage the rules are run consecutively. Nof the trailing comma rule is adding a trailing comma after the type
of variable "bar3". When the no-unused-import rule runs after the trailing-comma rule, it was incorrectly
seen as part of the type of variable "bar3" and a reference "EnumThree," (with the trailing comma was added)
which in turn resulted in not recognizing that the import of EnumThree actually was used.

Closes pinterest#1367

ktlint-ruleset-experimental/src/test/kotlin/com/pinterest/ktlint/ruleset/experimental/TrailingCommaRuleTest.kt

@@ -3,11 +3,13 @@ package com.pinterest.ktlint.ruleset.experimental
 import com.pinterest.ktlint.core.LintError
 import com.pinterest.ktlint.core.api.FeatureInAlphaState
 import com.pinterest.ktlint.ruleset.experimental.trailingcomma.TrailingCommaRule
+import com.pinterest.ktlint.ruleset.standard.NoUnusedImportsRule
 import com.pinterest.ktlint.test.EditorConfigTestRule
 import com.pinterest.ktlint.test.format
 import com.pinterest.ktlint.test.lint
 import org.assertj.core.api.Assertions.assertThat
 import org.ec4j.core.model.PropertyType
+import org.junit.Assert.assertTrue
 import org.junit.Rule
 import org.junit.Test
 
@@ -1043,6 +1045,64 @@ class TrailingCommaRuleTest {
             .isEqualTo(autoCorrectedCode)
     }
 
+    @Test
+    fun `Trailing comma and unused imports do not affect each other`() {
+        val code =
+            """
+            package com.pinterest.ktlint
+            import com.pinterest.ktlint.enum.Enum
+            import com.pinterest.ktlint.enum.EnumThree
+            import com.pinterest.ktlint.enum.EnumTwo
+            data class TrailingCommaTest(
+                val foo: String,
+                val bar: Enum,
+                val bar2: EnumTwo,
+                val bar3: EnumThree
+            )
+            """.trimIndent()
+        val formattedCode =
+            """
+            package com.pinterest.ktlint
+            import com.pinterest.ktlint.enum.Enum
+            import com.pinterest.ktlint.enum.EnumThree
+            import com.pinterest.ktlint.enum.EnumTwo
+            data class TrailingCommaTest(
+                val foo: String,
+                val bar: Enum,
+                val bar2: EnumTwo,
+                val bar3: EnumThree,
+            )
+            """.trimIndent()
+
+        val editorConfigFilePath = writeEditorConfigFile(
+            ALLOW_TRAILING_COMMA_ON_CALL_SITE,
+            ALLOW_TRAILING_COMMA_ON_DECLARATION_SITE
+        ).absolutePath
+        val rules = listOf(TrailingCommaRule(), NoUnusedImportsRule())
+        assertThat(rules.lint(editorConfigFilePath, code)).containsExactly(
+            LintError(9, 24, "trailing-comma", "Missing trailing comma before \")\"")
+        )
+        assertThat(rules.format(editorConfigFilePath, code)).isEqualTo(formattedCode)
+
+        // When running format mode, the rules are first executed in parallel to find linting errors. In this process,
+        // no unused import are found because the trailing comma is not yet added to variable "bar3". Then in the next
+        // stage the rules are run consecutively. Now the trailing comma rule is adding a trailing comma after the type
+        // of variable "bar3". When the no-unused-import rule runs after the trailing-comma rule, it was incorrectly
+        // seen as part of the type of variable "bar3" and a reference "EnumThree," (with the trailing comma was added)
+        // which in turn resulted in not recognizing that the import of EnumThree actually was used.
+        val afterFormatLintErrors = ArrayList<LintError>()
+        val formatResult = rules.format(editorConfigFilePath, code, cb = { e, _ -> afterFormatLintErrors.add(e) })
+        assertThat(afterFormatLintErrors).isEmpty()
+        assertThat(formatResult).isEqualTo(formattedCode)
+    }
+
+    @Test
+    fun assertTrue() {
+        val ktlintOutput = "Some unused import"
+
+        assertTrue(ktlintOutput.contains("unused import"))
+    }
+
     private fun writeEditorConfigFile(vararg editorConfigProperties: Pair<PropertyType<Boolean>, String>) = editorConfigTestRule
         .writeToEditorConfig(
             mapOf(*editorConfigProperties)

ktlint-ruleset-standard/src/main/kotlin/com/pinterest/ktlint/ruleset/standard/NoUnusedImportsRule.kt

@@ -3,6 +3,7 @@ package com.pinterest.ktlint.ruleset.standard
 import com.pinterest.ktlint.core.Rule
 import com.pinterest.ktlint.core.ast.ElementType.BY_KEYWORD
 import com.pinterest.ktlint.core.ast.ElementType.DOT_QUALIFIED_EXPRESSION
+import com.pinterest.ktlint.core.ast.ElementType.IDENTIFIER
 import com.pinterest.ktlint.core.ast.ElementType.IMPORT_DIRECTIVE
 import com.pinterest.ktlint.core.ast.ElementType.OPERATION_REFERENCE
 import com.pinterest.ktlint.core.ast.ElementType.PACKAGE_DIRECTIVE
@@ -12,6 +13,7 @@ import com.pinterest.ktlint.core.ast.isRoot
 import com.pinterest.ktlint.core.ast.visit
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.CompositeElement
 import org.jetbrains.kotlin.com.intellij.psi.tree.IElementType
 import org.jetbrains.kotlin.kdoc.lexer.KDocTokens
 import org.jetbrains.kotlin.kdoc.psi.impl.KDocLink
@@ -102,7 +104,17 @@ class NoUnusedImportsRule : Rule("no-unused-imports") {
                 } else if ((type == REFERENCE_EXPRESSION || type == OPERATION_REFERENCE) &&
                     !vnode.isPartOf(IMPORT_DIRECTIVE)
                 ) {
-                    ref.add(Reference(text.removeBackticksAndWildcards(), psi.parentDotQualifiedExpression() != null))
+                    val identifier = if (vnode is CompositeElement) {
+                        vnode.findChildByType(IDENTIFIER)
+                    } else {
+                        vnode
+                    }
+                    identifier
+                        ?.let { identifier.text }
+                        ?.takeIf { it.isNotBlank() }
+                        ?.let {
+                            ref.add(Reference(it.removeBackticksAndWildcards(), psi.parentDotQualifiedExpression() != null))
+                        }
                 } else if (type == IMPORT_DIRECTIVE) {
                     val importPath = (vnode.psi as KtImportDirective).importPath!!
                     if (!usedImportPaths.add(importPath)) {