[kotlin-dfa] KTIJ-35248 False positive: Constant conditions: "Condition is always false" with contract and Number subclass

Box types when processing contracts

GitOrigin-RevId: c09b52b2c2e5d5067ff95923df19372664882437

plugins/kotlin/code-insight/inspections-k2/src/org/jetbrains/kotlin/idea/k2/codeinsight/inspections/dfa/KotlinFunctionCallInstruction.kt

@@ -131,7 +131,7 @@ class KotlinFunctionCallInstruction(
                 ?.cond(RelationType.equivalence(!isNegated), factory.fromDfType(DfTypes.NULL))
 
             is KaContractIsInstancePredicateExpression -> argument.findDfaValue(callDescriptor, arguments)
-                ?.cond(if (isNegated) RelationType.IS_NOT else RelationType.IS, factory.fromDfType(type.toDfType()))
+                ?.cond(if (isNegated) RelationType.IS_NOT else RelationType.IS, factory.fromDfType(type.toDfReferenceType()))
 
             else -> null
         }

plugins/kotlin/code-insight/inspections-k2/src/org/jetbrains/kotlin/idea/k2/codeinsight/inspections/dfa/KtControlFlowBuilder.kt

@@ -364,8 +364,7 @@ class KtControlFlowBuilder(val factory: DfaValueFactory, val context: KtExpressi
         if (kotlinType is KaErrorType || kotlinType is KaTypeParameterType) return DfType.TOP
         val result = if (kotlinType.isMarkedNullable) kotlinType.toDfType()
         else {
-            // makeNullable to convert primitive to boxed
-            val dfType = kotlinType.withNullability(true).toDfType().meet(DfTypes.NOT_NULL_OBJECT)
+            val dfType = kotlinType.toDfReferenceType()
             if (dfType is DfReferenceType) dfType.dropSpecialField() else dfType
         }
         return if (result is DfReferenceType)

plugins/kotlin/code-insight/inspections-k2/src/org/jetbrains/kotlin/idea/k2/codeinsight/inspections/dfa/KtDfaHelpers.kt

@@ -51,6 +51,14 @@ internal fun KaType?.toDfType(): DfType {
     return toDfTypeNotNullable()
 }
 
+/**
+ * Convert KaType to DfReferenceType (primitive types are boxed)
+ */
+context(_: KaSession)
+internal fun KaType?.toDfReferenceType(): DfType {
+    return this?.withNullability(true).toDfType().meet(DfTypes.NOT_NULL_OBJECT)
+}
+
 context(_: KaSession)
 private fun KaType.toDfTypeNotNullable(): DfType {
     return when (this) {

plugins/kotlin/code-insight/inspections-k2/tests/test/org/jetbrains/kotlin/idea/k2/inspections/tests/K2DataFlowInspectionTest.kt

@@ -46,6 +46,7 @@ class K2DataFlowInspectionTest : AbstractK2InspectionTest() {
     fun testConstantDivisionByZero() = doTest()
     fun testConstantWithDifferentType() = doTest()
     fun testContextParameter() = doTest()
+    fun testContractForNumber() = doTest()
     fun testCustomObjectComparisonK2() = doTest()
     fun testDestructuringInLoop() = doTest()
     fun testDoubleComparison() = doTest()

plugins/kotlin/idea/tests/testData/inspections/dfa/ContractForNumber.kt

@@ -0,0 +1,14 @@
+// WITH_STDLIB
+import kotlin.contracts.ExperimentalContracts
+import kotlin.contracts.contract
+
+fun foo(number: Number) {
+    if (myPredicate(number))
+        println(number)
+}
+
+@OptIn(ExperimentalContracts::class)
+fun myPredicate(n: Number): Boolean {
+    contract { returns(true) implies (n is Int) }
+    return n is Int
+}