[FIR] Add a fallback source element for `TYPE_PARAMETERS_IN_ENUM`

^KT-77149 Fixed
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt
index b45ae65..ee98d98 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/declaration/FirEnumClassSimpleChecker.kt
@@ -33,7 +33,7 @@
             ?.let { reporter.reportOn(it.source, FirErrors.CLASS_IN_SUPERTYPE_FOR_ENUM) }
 
         if (declaration.typeParameters.isNotEmpty()) {
-            reporter.reportOn(declaration.typeParameters.firstOrNull()?.source, FirErrors.TYPE_PARAMETERS_IN_ENUM)
+            reporter.reportOn(declaration.typeParameters.firstOrNull()?.source ?: declaration.source, FirErrors.TYPE_PARAMETERS_IN_ENUM)
         }
     }
 }
diff --git a/compiler/testData/diagnostics/tests/localNestedEnumCapturesOuterTypeParameters.fir.fail b/compiler/testData/diagnostics/tests/localNestedEnumCapturesOuterTypeParameters.fir.fail
deleted file mode 100644
index 03f696b..0000000
--- a/compiler/testData/diagnostics/tests/localNestedEnumCapturesOuterTypeParameters.fir.fail
+++ /dev/null
@@ -1,9 +0,0 @@
-java.lang.IllegalArgumentException: source must not be null
-    at org.jetbrains.kotlin.diagnostics.KtDiagnosticReportHelpersKt.requireNotNull(KtDiagnosticReportHelpers.kt:213)
-    at org.jetbrains.kotlin.diagnostics.KtDiagnosticReportHelpersKt.reportOn(KtDiagnosticReportHelpers.kt:43)
-    at org.jetbrains.kotlin.diagnostics.KtDiagnosticReportHelpersKt.reportOn$default(KtDiagnosticReportHelpers.kt:37)
-    at org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirEnumClassSimpleChecker.check(FirEnumClassSimpleChecker.kt:36)
-    at org.jetbrains.kotlin.fir.analysis.checkers.declaration.FirEnumClassSimpleChecker.check(FirEnumClassSimpleChecker.kt:21)
-    at org.jetbrains.kotlin.fir.analysis.checkers.declaration.DeclarationCheckersDiagnosticComponent.visitRegularClass(DeclarationCheckersDiagnosticComponent.kt:275)
-    at org.jetbrains.kotlin.fir.analysis.checkers.declaration.DeclarationCheckersDiagnosticComponent.visitRegularClass(DeclarationCheckersDiagnosticComponent.kt:25)
-    at org.jetbrains.kotlin.fir.declarations.FirRegularClass.accept(FirRegularClass.kt:49)
diff --git a/compiler/testData/diagnostics/tests/localNestedEnumCapturesOuterTypeParameters.fir.kt b/compiler/testData/diagnostics/tests/localNestedEnumCapturesOuterTypeParameters.fir.kt
index e6fb8df6..9bd0590 100644
--- a/compiler/testData/diagnostics/tests/localNestedEnumCapturesOuterTypeParameters.fir.kt
+++ b/compiler/testData/diagnostics/tests/localNestedEnumCapturesOuterTypeParameters.fir.kt
@@ -5,8 +5,8 @@
     abstract class ShorteningProcessor<TElement> {
         fun analyzeCollectedElements() = E.A == E.A
 
-        enum class E {
+        <!TYPE_PARAMETERS_IN_ENUM!><!WRONG_MODIFIER_TARGET!>enum<!> class E {
             A;
-        }
+        }<!>
     }
 }