diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConstChecks.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConstChecks.kt
index 5ad8756c38d..b6199fab329 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConstChecks.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/checkers/FirConstChecks.kt
@@ -89,6 +89,15 @@ internal fun checkConstantArguments(
             )
                 return ConstantArgumentKind.NOT_CONST
         }
+        expressionSymbol is FirConstructor -> {
+            if (expression.typeRef.coneType.isUnsignedType) {
+                (expression as FirFunctionCall).arguments.forEach { argumentExpression ->
+                    checkConstantArguments(argumentExpression, session)?.let { return it }
+                }
+            } else {
+                return ConstantArgumentKind.NOT_CONST
+            }
+        }
         expression is FirFunctionCall -> {
             val calleeReference = expression.calleeReference
             if (calleeReference is FirErrorNamedReference) {
@@ -103,6 +112,7 @@ internal fun checkConstantArguments(
                 return null
             }
 
+
             when (calleeReference.name) {
                 in OperatorNameConventions.BINARY_OPERATION_NAMES, in OperatorNameConventions.UNARY_OPERATION_NAMES,
                 OperatorNameConventions.SHL, OperatorNameConventions.SHR, OperatorNameConventions.USHR,
diff --git a/compiler/testData/codegen/bytecodeText/constants/inlineUnsignedIntConstant.kt b/compiler/testData/codegen/bytecodeText/constants/inlineUnsignedIntConstant.kt
index aaeae9efd69..bf888eca433 100644
--- a/compiler/testData/codegen/bytecodeText/constants/inlineUnsignedIntConstant.kt
+++ b/compiler/testData/codegen/bytecodeText/constants/inlineUnsignedIntConstant.kt
@@ -1,5 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND_FIR: JVM_IR
 
 // FILE: uint.kt
 
@@ -9,6 +8,9 @@ inline class UInt(val value: Int)
 
 // FILE: test.kt
 
+//this import in required in FIR because default imports don't search in local sources atm
+import kotlin.UInt
+
 const val u = UInt(14)
 
 fun foo() {
diff --git a/compiler/testData/diagnostics/tests/unsignedTypes/allowedVarargsOfUnsignedTypes.fir.kt b/compiler/testData/diagnostics/tests/unsignedTypes/allowedVarargsOfUnsignedTypes.fir.kt
deleted file mode 100644
index e25d1f0d2b7..00000000000
--- a/compiler/testData/diagnostics/tests/unsignedTypes/allowedVarargsOfUnsignedTypes.fir.kt
+++ /dev/null
@@ -1,12 +0,0 @@
-// !DIAGNOSTICS: -UNUSED_PARAMETER
-
-fun ubyte(vararg a: UByte) {}
-fun ushort(vararg a: UShort) {}
-fun uint(vararg a: UInt) {}
-fun ulong(vararg a: ULong) {}
-
-class ValueParam(vararg val a: ULong)
-
-annotation class Ann(vararg val a: <!INVALID_TYPE_OF_ANNOTATION_MEMBER!>UInt<!>)
-
-fun array(<!FORBIDDEN_VARARG_PARAMETER_TYPE!>vararg<!> a: UIntArray) {}
diff --git a/compiler/testData/diagnostics/tests/unsignedTypes/allowedVarargsOfUnsignedTypes.kt b/compiler/testData/diagnostics/tests/unsignedTypes/allowedVarargsOfUnsignedTypes.kt
index bd99c3ecfec..fbf95cf3401 100644
--- a/compiler/testData/diagnostics/tests/unsignedTypes/allowedVarargsOfUnsignedTypes.kt
+++ b/compiler/testData/diagnostics/tests/unsignedTypes/allowedVarargsOfUnsignedTypes.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 fun ubyte(vararg a: UByte) {}