diff --git a/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/AbstractDiagnosticsTest.kt b/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/AbstractDiagnosticsTest.kt
index 919c6055f33..8e2157d18ca 100644
--- a/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/AbstractDiagnosticsTest.kt
+++ b/compiler/tests-common/tests/org/jetbrains/kotlin/checkers/AbstractDiagnosticsTest.kt
@@ -9,6 +9,7 @@ import com.intellij.openapi.util.io.FileUtil
 import com.intellij.openapi.util.text.StringUtil
 import com.intellij.psi.PsiElement
 import com.intellij.psi.search.GlobalSearchScope
+import com.intellij.rt.execution.junit.FileComparisonFailure
 import junit.framework.AssertionFailedError
 import junit.framework.TestCase
 import org.jetbrains.kotlin.TestsCompilerError
@@ -281,7 +282,16 @@ abstract class AbstractDiagnosticsTest : BaseDiagnosticsTest() {
             }
         }
         if (testDataFile.readText().contains("// FIR_IDENTICAL")) {
-            testRunner.analyzeAndCheckUnhandled(testDataFile, files)
+            try {
+                testRunner.analyzeAndCheckUnhandled(testDataFile, files)
+            } catch (e: FileComparisonFailure) {
+                println("Old FE & FIR produces different diagnostics for this file. Please remove FIR_IDENTICAL line manually")
+                throw FileComparisonFailure(
+                    "Old FE & FIR produces different diagnostics for this file. Please remove FIR_IDENTICAL line manually\n" +
+                            e.message,
+                    e.expected, e.actual, e.filePath, e.actualFilePath
+                )
+            }
         } else {
             FileUtil.copy(testDataFile, firTestDataFile)
             testRunner.analyzeAndCheckUnhandled(firTestDataFile, files)
diff --git a/compiler/tests-common/tests/org/jetbrains/kotlin/fir/FirTestUtils.kt b/compiler/tests-common/tests/org/jetbrains/kotlin/fir/FirTestUtils.kt
index cb2e652f5a2..9327ca6cc23 100644
--- a/compiler/tests-common/tests/org/jetbrains/kotlin/fir/FirTestUtils.kt
+++ b/compiler/tests-common/tests/org/jetbrains/kotlin/fir/FirTestUtils.kt
@@ -36,7 +36,9 @@ fun compareAndMergeFirFileAndOldFrontendFile(
             oldFrontendTestDataFile.writeText("// FIR_IDENTICAL\n" + oldFrontendTestDataFile.readText())
         }
         TestCase.assertFalse(
-            "Dumps via FIR & via old FE are the same. Deleted .fir.txt dump, added // FIR_IDENTICAL to test source",
+            "Dumps via FIR & via old FE are the same. " +
+                    "\nDeleted .fir.txt dump, added // FIR_IDENTICAL to test source" +
+                    "\nPlease re-run the test now",
             sameDumps
         )
     }