[FIR] Add separate diagnostic tests working in light tree mode

Now we have separate raw fir builder based and light tree builder based tests.
Note: one light tree test was ignored due to lack of JavaElementFinder in this mode.

compiler/fir/resolve/testData/resolve/samConversions/samWithEquals.kt

@@ -1,3 +1,5 @@
+// IGNORE_LIGHT_TREE
+// Does not work in light tree mode due to lack of Java element finder there
 // FILE: KotlinTypeChecker.java
 
 public interface KotlinTypeChecker {

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/AbstractFirBaseDiagnosticsTest.kt

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.fir.declarations.FirFile
 import org.jetbrains.kotlin.fir.java.FirJavaModuleBasedSession
 import org.jetbrains.kotlin.fir.java.FirLibrarySession
 import org.jetbrains.kotlin.fir.java.FirProjectSessionProvider
+import org.jetbrains.kotlin.fir.lightTree.LightTree2Fir
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeDiagnostic
 import org.jetbrains.kotlin.fir.resolve.firProvider
 import org.jetbrains.kotlin.fir.resolve.impl.FirProviderImpl
@@ -35,6 +36,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.platform.TargetPlatform
 import org.jetbrains.kotlin.platform.jvm.JvmPlatforms
+import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.resolve.AnalyzingUtils
 import org.jetbrains.kotlin.resolve.PlatformDependentAnalyzerServices
 import org.jetbrains.kotlin.resolve.jvm.platform.JvmPlatformAnalyzerServices
@@ -60,7 +62,7 @@ abstract class AbstractFirBaseDiagnosticsTest : BaseDiagnosticsTest() {
         }
     }
 
-    protected open fun analyzeAndCheckUnhandled(testDataFile: File, files: List<TestFile>) {
+    open fun analyzeAndCheckUnhandled(testDataFile: File, files: List<TestFile>, useLightTree: Boolean = false) {
         val groupedByModule = files.groupBy(TestFile::module)
 
         val modules = createModules(groupedByModule)
@@ -90,21 +92,30 @@ abstract class AbstractFirBaseDiagnosticsTest : BaseDiagnosticsTest() {
 
             val session = configToSession.getValue(testModule)
 
-
-            val firBuilder = RawFirBuilder(session, false)
-
-            ktFiles.mapTo(firFiles) {
-                val firFile = firBuilder.buildFirFile(it)
-
-                (session.firProvider as FirProviderImpl).recordFile(firFile)
-
-                firFile
-            }
+            mapKtFilesToFirFiles(session, ktFiles, firFiles, useLightTree)
         }
 
         runAnalysis(testDataFile, files, firFiles)
     }
 
+    private fun mapKtFilesToFirFiles(session: FirSession, ktFiles: List<KtFile>, firFiles: MutableList<FirFile>, useLightTree: Boolean) {
+        if (useLightTree) {
+            val lightTreeBuilder = LightTree2Fir(session, stubMode = false)
+            ktFiles.mapTo(firFiles) {
+                val firFile = lightTreeBuilder.buildFirFile(it.text, it.name)
+                (session.firProvider as FirProviderImpl).recordFile(firFile)
+                firFile
+            }
+        } else {
+            val firBuilder = RawFirBuilder(session, false)
+            ktFiles.mapTo(firFiles) {
+                val firFile = firBuilder.buildFirFile(it)
+                (session.firProvider as FirProviderImpl).recordFile(firFile)
+                firFile
+            }
+        }
+    }
+
     protected abstract fun runAnalysis(testDataFile: File, testFiles: List<TestFile>, firFiles: List<FirFile>)
 
     private fun createModules(

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/AbstractFirDiagnosticsWithLightTreeTest.kt

@@ -0,0 +1,24 @@
+/*
+ * Copyright 2010-2019 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 org.jetbrains.kotlin.test.InTextDirectivesUtils
+import org.jetbrains.kotlin.test.KotlinTestUtils
+import java.io.File
+
+abstract class AbstractFirDiagnosticsWithLightTreeTest : AbstractFirDiagnosticsTest(), FirDiagnosticsTestLightTreeHelper {
+    override fun doTest(filePath: String) {
+        val file = createTestFileFromPath(filePath)
+        val expectedText = KotlinTestUtils.doLoadFile(file)
+        if (InTextDirectivesUtils.isDirectiveDefined(expectedText, "// IGNORE_LIGHT_TREE")) return
+
+        super.doTest(filePath)
+    }
+
+    override fun analyzeAndCheck(testDataFile: File, files: List<TestFile>) {
+        super<FirDiagnosticsTestLightTreeHelper>.analyzeAndCheck(testDataFile, files)
+    }
+}

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirDiagnosticsTestLightTreeHelper.kt

@@ -0,0 +1,23 @@
+/*
+ * Copyright 2010-2019 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 org.jetbrains.kotlin.checkers.BaseDiagnosticsTest
+import java.io.File
+
+interface FirDiagnosticsTestLightTreeHelper {
+    fun analyzeAndCheck(testDataFile: File, files: List<BaseDiagnosticsTest.TestFile>) {
+        try {
+            analyzeAndCheckUnhandled(testDataFile, files, useLightTree = true)
+        } catch (t: AssertionError) {
+            throw t
+        } catch (t: Throwable) {
+            throw t
+        }
+    }
+
+    fun analyzeAndCheckUnhandled(testDataFile: File, files: List<BaseDiagnosticsTest.TestFile>, useLightTree: Boolean)
+}

compiler/tests/org/jetbrains/kotlin/generators/tests/GenerateCompilerTests.kt

@@ -531,6 +531,10 @@ fun main(args: Array<String>) {
             model("resolve", pattern = KT_WITHOUT_DOTS_IN_NAME, excludeDirs = listOf("stdlib", "cfg", "smartcasts"))
         }
 
+        testClass<AbstractFirDiagnosticsWithLightTreeTest> {
+            model("resolve", pattern = KT_WITHOUT_DOTS_IN_NAME, excludeDirs = listOf("stdlib", "cfg", "smartcasts"))
+        }
+
         testClass<AbstractFirDiagnosticsWithCfgTest> {
             model("resolve/cfg", pattern = KT_WITHOUT_DOTS_IN_NAME)
             model("resolve/smartcasts", pattern = KT_WITHOUT_DOTS_IN_NAME)