[FIR] Add illegal underscore diagnostic

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/collectors/components/ErrorNodeDiagnosticCollectorComponent.kt

@@ -70,6 +70,7 @@ class ErrorNodeDiagnosticCollectorComponent(collector: AbstractDiagnosticCollect
             ReturnNotAllowed -> FirErrors.RETURN_NOT_ALLOWED
             UnresolvedLabel -> FirErrors.UNRESOLVED_LABEL
             IllegalConstExpression -> FirErrors.ILLEGAL_CONST_EXPRESSION
+            IllegalUnderscore -> FirErrors.ILLEGAL_UNDERSCORE
             DeserializationError -> FirErrors.DESERIALIZATION_ERROR
             InferenceError -> FirErrors.INFERENCE_ERROR
             TypeParameterAsSupertype -> FirErrors.TYPE_PARAMETER_AS_SUPERTYPE

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirDefaultErrorMessages.kt

@@ -23,6 +23,7 @@ import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.EXPOSED_PROPERTY_
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.EXPOSED_RECEIVER_TYPE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.EXPOSED_TYPEALIAS_EXPANDED_TYPE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ILLEGAL_CONST_EXPRESSION
+import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.ILLEGAL_UNDERSCORE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INAPPLICABLE_CANDIDATE
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INCOMPATIBLE_MODIFIERS
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirErrors.INFERENCE_ERROR
@@ -53,6 +54,7 @@ class FirDefaultErrorMessages : DefaultErrorMessages.Extension {
             map.put(SYNTAX_ERROR, "Syntax error")
             map.put(UNRESOLVED_LABEL, "Unresolved label")
             map.put(ILLEGAL_CONST_EXPRESSION, "Illegal const expression")
+            map.put(ILLEGAL_UNDERSCORE, "Illegal underscore")
             map.put(DESERIALIZATION_ERROR, "Deserialization error")
             map.put(INFERENCE_ERROR, "Inference error")
             map.put(TYPE_PARAMETER_AS_SUPERTYPE, "Type parameter as supertype")

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt

@@ -27,6 +27,7 @@ object FirErrors {
     val SYNTAX_ERROR by error0<FirSourceElement, PsiElement>()
     val UNRESOLVED_LABEL by error0<FirSourceElement, PsiElement>()
     val ILLEGAL_CONST_EXPRESSION by error0<FirSourceElement, PsiElement>()
+    val ILLEGAL_UNDERSCORE by error0<FirSourceElement, PsiElement>()
     val DESERIALIZATION_ERROR by error0<FirSourceElement, PsiElement>()
     val INFERENCE_ERROR by error0<FirSourceElement, PsiElement>()
     val TYPE_PARAMETER_AS_SUPERTYPE by error0<FirSourceElement, PsiElement>()

compiler/fir/tree/src/org/jetbrains/kotlin/fir/diagnostics/ConeSimpleDiagnostic.kt

@@ -17,6 +17,7 @@ enum class DiagnosticKind {
     ReturnNotAllowed,
     UnresolvedLabel,
     IllegalConstExpression,
+    IllegalUnderscore,
     DeserializationError,
     InferenceError,
     TypeParameterAsSupertype,