FIR: move FirModifierList to module 'fir:checkers'

To remove dependency of a large module 'fir:tree' on 'psi', allowing
them to compile in parallel.

compiler/fir/tree/build.gradle.kts

@@ -6,7 +6,6 @@ plugins {
 }
 
 dependencies {
-    compile(project(":compiler:psi"))
     compile(project(":compiler:frontend.common"))
     compile(project(":core:descriptors"))
     compile(project(":compiler:fir:cones"))

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirModifierList.kt

@@ -1,70 +0,0 @@
-/*
- * Copyright 2010-2020 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.fir
-
-import com.intellij.lang.ASTNode
-import com.intellij.lang.LighterASTNode
-import com.intellij.openapi.util.Ref
-import com.intellij.psi.PsiElement
-import com.intellij.psi.tree.TokenSet
-import com.intellij.util.diff.FlyweightCapableTreeStructure
-import org.jetbrains.kotlin.lexer.KtModifierKeywordToken
-import org.jetbrains.kotlin.lexer.KtTokens
-import org.jetbrains.kotlin.psi.KtModifierList
-
-sealed class FirModifierList {
-    abstract val modifiers: List<FirModifier<*>>
-}
-
-private val MODIFIER_KEYWORD_SET = TokenSet.orSet(KtTokens.SOFT_KEYWORDS, TokenSet.create(KtTokens.IN_KEYWORD, KtTokens.FUN_KEYWORD))
-
-class FirPsiModifierList(val modifierList: KtModifierList) : FirModifierList() {
-    override val modifiers: List<FirPsiModifier>
-        get() = modifierList.node.getChildren(MODIFIER_KEYWORD_SET).map { node ->
-            FirPsiModifier(node, node.elementType as KtModifierKeywordToken)
-        }
-
-}
-
-class FirLightModifierList(val modifierList: LighterASTNode, val tree: FlyweightCapableTreeStructure<LighterASTNode>) : FirModifierList() {
-    override val modifiers: List<FirLightModifier>
-        get() {
-            val kidsRef = Ref<Array<LighterASTNode?>>()
-            tree.getChildren(modifierList, kidsRef)
-            val modifierNodes = kidsRef.get()
-            return modifierNodes.filterNotNull()
-                .filter { it.tokenType is KtModifierKeywordToken }
-                .map { FirLightModifier(it, it.tokenType as KtModifierKeywordToken, tree) }
-        }
-}
-
-sealed class FirModifier<Node : Any>(val node: Node, val token: KtModifierKeywordToken)
-
-class FirPsiModifier(
-    node: ASTNode,
-    token: KtModifierKeywordToken
-) : FirModifier<ASTNode>(node, token)
-
-class FirLightModifier(
-    node: LighterASTNode,
-    token: KtModifierKeywordToken,
-    val tree: FlyweightCapableTreeStructure<LighterASTNode>
-) : FirModifier<LighterASTNode>(node, token)
-
-val FirModifier<*>.psi: PsiElement? get() = (this as? FirPsiModifier)?.node?.psi
-
-val FirModifier<*>.lightNode: LighterASTNode? get() = (this as? FirLightModifier)?.node
-
-val FirModifier<*>.source: FirSourceElement?
-    get() = when (this) {
-        is FirPsiModifier -> this.psi?.toFirPsiSourceElement()
-        is FirLightModifier -> {
-            // TODO pretty sure I got offsets wrong here
-            val startOffset = tree.getStartOffset(node)
-            val endOffset = tree.getEndOffset(node)
-            node.toFirLightSourceElement(startOffset, endOffset, tree)
-        }
-    }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt

@@ -6,14 +6,9 @@
 package org.jetbrains.kotlin.fir
 
 import com.intellij.lang.LighterASTNode
-import com.intellij.openapi.util.Ref
 import com.intellij.psi.PsiElement
 import com.intellij.psi.tree.IElementType
 import com.intellij.util.diff.FlyweightCapableTreeStructure
-import org.jetbrains.kotlin.KtNodeTypes
-import org.jetbrains.kotlin.psi.KtModifierListOwner
-import org.jetbrains.kotlin.psi.psiUtil.endOffset
-import org.jetbrains.kotlin.psi.psiUtil.startOffset
 
 sealed class FirSourceElement {
     abstract val elementType: IElementType
@@ -26,10 +21,10 @@ class FirPsiSourceElement<P : PsiElement>(val psi: P) : FirSourceElement() {
         get() = psi.node.elementType
 
     override val startOffset: Int
-        get() = psi.startOffset
+        get() = psi.textRange.startOffset
 
     override val endOffset: Int
-        get() = psi.endOffset
+        get() = psi.textRange.endOffset
 }
 
 class FirLightSourceElement(
@@ -56,16 +51,3 @@ inline fun LighterASTNode.toFirLightSourceElement(
 ): FirLightSourceElement = FirLightSourceElement(this, startOffset, endOffset, tree)
 
 val FirSourceElement?.lightNode: LighterASTNode? get() = (this as? FirLightSourceElement)?.element
-
-fun FirSourceElement?.getModifierList(): FirModifierList? {
-    return when (this) {
-        null -> null
-        is FirPsiSourceElement<*> -> (psi as? KtModifierListOwner)?.modifierList?.let { FirPsiModifierList(it) }
-        is FirLightSourceElement -> {
-            val kidsRef = Ref<Array<LighterASTNode?>>()
-            tree.getChildren(element, kidsRef)
-            val modifierListNode = kidsRef.get().find { it?.tokenType == KtNodeTypes.MODIFIER_LIST } ?: return null
-            FirLightModifierList(modifierListNode, tree)
-        }
-    }
-}