Fixed WRONG_MULTIPLE_MODIFIERS_ORDER bug in SAM interface

diktat-rules/src/main/kotlin/org/cqfn/diktat/ruleset/rules/chapter3/MultipleModifiersSequence.kt

@@ -3,13 +3,17 @@ package org.cqfn.diktat.ruleset.rules.chapter3
 import org.cqfn.diktat.common.config.rules.RulesConfig
 import org.cqfn.diktat.ruleset.constants.Warnings.WRONG_MULTIPLE_MODIFIERS_ORDER
 import org.cqfn.diktat.ruleset.rules.DiktatRule
+import org.cqfn.diktat.ruleset.utils.findAllDescendantsWithSpecificType
 
 import com.pinterest.ktlint.core.ast.ElementType.ANNOTATION_ENTRY
+import com.pinterest.ktlint.core.ast.ElementType.FUN
+import com.pinterest.ktlint.core.ast.ElementType.FUN_KEYWORD
 import com.pinterest.ktlint.core.ast.ElementType.MODIFIER_LIST
 import com.pinterest.ktlint.core.ast.ElementType.WHITE_SPACE
 import org.jetbrains.kotlin.com.intellij.lang.ASTNode
 import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.PsiWhiteSpaceImpl
 import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.psi.KtClass
 import org.jetbrains.kotlin.psi.psiUtil.children
 
 /**
@@ -31,6 +35,9 @@ class MultipleModifiersSequence(configRules: List<RulesConfig>) : DiktatRule(
         val modifierListOfPair = node
             .getChildren(KtTokens.MODIFIER_KEYWORDS)
             .toList()
+            .filter {
+                !isSamInterfaces(node, it)
+            }
             .map { Pair(it, modifierOrder.indexOf(it.elementType)) }
         val sortModifierListOfPair = modifierListOfPair.sortedBy { it.second }.map { it.first }
         modifierListOfPair.forEachIndexed { index, (modifierNode, _) ->
@@ -46,6 +53,15 @@ class MultipleModifiersSequence(configRules: List<RulesConfig>) : DiktatRule(
         }
     }
 
+    private fun isSamInterfaces(parent: ASTNode, node: ASTNode): Boolean {
+        val parentPsi = parent.treeParent.psi
+        return if (parentPsi is KtClass) {
+            (parentPsi.isInterface()) && node.elementType == FUN_KEYWORD && parent.treeParent.findAllDescendantsWithSpecificType(FUN).size == 1
+        } else {
+            false
+        }
+    }
+
     private fun checkAnnotation(node: ASTNode) {
         val firstModifierIndex = node
             .children()

diktat-rules/src/test/resources/test/paragraph3/multiple_modifiers/ModifierExpected.kt

@@ -11,3 +11,7 @@ protected data class Counter(val dayIndex: Int) {
 public final fun foo() {
     protected open lateinit var a: List<ASTNode>
 }
+
+public internal fun interface Factory {
+    public fun create(): List<Int>
+}

diktat-rules/src/test/resources/test/paragraph3/multiple_modifiers/ModifierTest.kt

@@ -11,3 +11,7 @@ data protected class Counter(val dayIndex: Int) {
 final public fun foo() {
     lateinit open protected var a: List<ASTNode>
 }
+
+internal public fun interface Factory {
+    public fun create(): List<Int>
+}