Relax rules for type parameters in property receivers

compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt

@@ -450,9 +450,26 @@ class DeclarationsChecker(
     }
 
     private fun checkPropertyTypeParametersAreUsedInReceiverType(descriptor: PropertyDescriptor) {
-        for (typeParameter in descriptor.typeParameters) {
-            if (isTypeParameterUsedInReceiverType(typeParameter, descriptor)) continue
+        val allTypeParameters = descriptor.typeParameters.toSet()
+        val allAccessibleTypeParameters = HashSet<TypeParameterDescriptor>()
 
+        fun addAccessibleTypeParametersFromType(type: KotlinType?) {
+            TypeUtils.contains(type) {
+                val declarationDescriptor = it.constructor.declarationDescriptor
+                if (declarationDescriptor is TypeParameterDescriptor && declarationDescriptor in allTypeParameters) {
+                    if (allAccessibleTypeParameters.add(declarationDescriptor)) {
+                        declarationDescriptor.upperBounds.forEach {
+                            addAccessibleTypeParametersFromType(it)
+                        }
+                    }
+                }
+                false
+            }
+        }
+        addAccessibleTypeParametersFromType(descriptor.extensionReceiverParameter?.type)
+
+        val typeParametersInaccessibleFromReceiver = allTypeParameters - allAccessibleTypeParameters
+        for (typeParameter in typeParametersInaccessibleFromReceiver) {
             val typeParameterPsi = DescriptorToSourceUtils.getSourceFromDescriptor(typeParameter)
             if (typeParameterPsi is KtTypeParameter) {
                 trace.report(TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER.on(typeParameterPsi))
@@ -838,14 +855,6 @@ class DeclarationsChecker(
             return !modifierList.hasModifier(KtTokens.OVERRIDE_KEYWORD)
         }
 
-        private fun isTypeParameterUsedInReceiverType(
-                parameter: TypeParameterDescriptor,
-                descriptor: PropertyDescriptor): Boolean {
-            val receiverParameter = descriptor.extensionReceiverParameter ?: return false
-
-            return TypeUtils.contains(receiverParameter.type) { parameter == it.constructor.declarationDescriptor }
-        }
-
         private fun hasDefaultConstructor(classDescriptor: ClassDescriptor) =
                 classDescriptor.constructors.any { it.valueParameters.isEmpty() }
 

compiler/testData/diagnostics/tests/typeParameters/propertyTypeParameters.kt

@@ -30,4 +30,15 @@ class C<T1, T2> {
     val <E> E.c: Int get() = 3
     val <<!TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER!>E<!>> Map<T1, T2>.d: Int get() = 3
     val <E> Map<T1, E>.e: Int get() = 3
-}
+}
+
+val <T : Enum<T>> T.z1: Int
+    get() = 4
+
+interface D<T : Enum<T>>
+
+val <X: D<*>> X.z2: Int
+    get() = 4
+
+val <<!TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER!>Y<!>> D<*>.z3: Int
+    get() = 4

compiler/testData/diagnostics/tests/typeParameters/propertyTypeParameters.txt

@@ -10,6 +10,9 @@ public val </*0*/ T> kotlin.collections.List<kotlin.collections.Map<kotlin.Int,
 public val </*0*/ T> kotlin.collections.List<kotlin.collections.Map<kotlin.Int, kotlin.collections.Map<kotlin.String, out T>>>.g: kotlin.Int
 public val </*0*/ T> kotlin.collections.List<kotlin.collections.Map<kotlin.Int, kotlin.collections.Map<kotlin.String, in T>>>.h: kotlin.Int
 public val </*0*/ T> kotlin.collections.List<kotlin.collections.Map<T, kotlin.collections.Map<T, T>>>.i: kotlin.Int
+public val </*0*/ T : kotlin.Enum<T>> T.z1: kotlin.Int
+public val </*0*/ X : D<*>> X.z2: kotlin.Int
+public val </*0*/ Y> D<*>.z3: kotlin.Int
 
 public final class C</*0*/ T1, /*1*/ T2> {
     public constructor C</*0*/ T1, /*1*/ T2>()
@@ -23,6 +26,12 @@ public final class C</*0*/ T1, /*1*/ T2> {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
+public interface D</*0*/ T : kotlin.Enum<T>> {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
 public interface G {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int

compiler/testData/diagnostics/tests/typeParameters/propertyTypeParametersWithUpperBounds.kt

@@ -0,0 +1,28 @@
+
+val <<!TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER!>T : K<!>, K> K.a: Int get() = 4
+
+val <<!TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER!>T<!>, K> K.b: Int where T : K
+    get() = 4
+
+val <<!TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER!>T<!>, K> K.c: Int where T : List<K>
+    get() = 4
+
+val <T, K> K.d: Int where K : T
+    get() = 4
+
+val <T, K> K.e: Int where K : List<T>
+    get() = 4
+
+interface G
+val <<!TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER!>T<!>> G.x1: Int where T : G
+    get() = 4
+
+
+val <<!TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER!>X<!>, Y, Z> Z.x2: Int where X : Y, Z : Y
+    get() = 4
+
+val <X, Y: Map<Z, X>, Z: List<List<Y>>> Z.x3: Int
+    get() = 5
+
+val <X, Y: Map<X, List<Z>>, Z> Map<X, List<Y>>.x4: Int
+    get() = 5

compiler/testData/diagnostics/tests/typeParameters/propertyTypeParametersWithUpperBounds.txt

@@ -0,0 +1,17 @@
+package
+
+public val </*0*/ T : K, /*1*/ K> K.a: kotlin.Int
+public val </*0*/ T : K, /*1*/ K> K.b: kotlin.Int
+public val </*0*/ T : kotlin.collections.List<K>, /*1*/ K> K.c: kotlin.Int
+public val </*0*/ T, /*1*/ K : T> K.d: kotlin.Int
+public val </*0*/ T, /*1*/ K : kotlin.collections.List<T>> K.e: kotlin.Int
+public val </*0*/ T : G> G.x1: kotlin.Int
+public val </*0*/ X : Y, /*1*/ Y, /*2*/ Z : Y> Z.x2: kotlin.Int
+public val </*0*/ X, /*1*/ Y : kotlin.collections.Map<Z, X>, /*2*/ Z : kotlin.collections.List<kotlin.collections.List<Y>>> Z.x3: kotlin.Int
+public val </*0*/ X, /*1*/ Y : kotlin.collections.Map<X, kotlin.collections.List<Z>>, /*2*/ Z> kotlin.collections.Map<X, kotlin.collections.List<Y>>.x4: kotlin.Int
+
+public interface G {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -18153,6 +18153,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("propertyTypeParametersWithUpperBounds.kt")
+            public void testPropertyTypeParametersWithUpperBounds() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/typeParameters/propertyTypeParametersWithUpperBounds.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("repeatedBound.kt")
             public void testRepeatedBound() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/typeParameters/repeatedBound.kt");