Disconnect loops between upper bounds of type parameters

#KT-9759 Fixed

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -416,7 +416,7 @@ public class DefaultErrorMessages {
 
         MAP.put(TYPE_MISMATCH_IN_RANGE, "Type mismatch: incompatible types of range and element checked in it");
         MAP.put(CYCLIC_INHERITANCE_HIERARCHY, "There's a cycle in the inheritance hierarchy for this type");
-        MAP.put(CYCLIC_GENERIC_UPPER_BOUND, "Type parameter has itself as an upper bound");
+        MAP.put(CYCLIC_GENERIC_UPPER_BOUND, "Type parameter has cyclic upper bounds");
 
         MAP.put(MANY_CLASSES_IN_SUPERTYPE_LIST, "Only one class may appear in a supertype list");
         MAP.put(SUPERTYPE_NOT_A_CLASS_OR_INTERFACE, "Only classes and interfaces may serve as supertypes");

compiler/frontend/src/org/jetbrains/kotlin/resolve/DescriptorResolver.java

@@ -23,6 +23,7 @@ import com.intellij.psi.PsiElement;
 import kotlin.CollectionsKt;
 import kotlin.SetsKt;
 import kotlin.jvm.functions.Function0;
+import kotlin.jvm.functions.Function1;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
@@ -410,9 +411,9 @@ public class DescriptorResolver {
             DeclarationDescriptor containingDescriptor,
             LexicalWritableScope extensibleScope,
             LexicalScope scopeForAnnotationsResolve,
-            KtTypeParameter typeParameter,
+            final KtTypeParameter typeParameter,
             int index,
-            BindingTrace trace
+            final BindingTrace trace
     ) {
         if (typeParameter.getVariance() != Variance.INVARIANT) {
             assert !(containingDescriptor instanceof ClassifierDescriptor) : "This method is intended for functions/properties";
@@ -429,8 +430,16 @@ public class DescriptorResolver {
                 typeParameter.getVariance(),
                 KtPsiUtil.safeName(typeParameter.getName()),
                 index,
-                KotlinSourceElementKt.toSourceElement(typeParameter)
-        );
+                KotlinSourceElementKt.toSourceElement(typeParameter),
+                new Function1<KotlinType, Void>() {
+                    @Override
+                    public Void invoke(KotlinType type) {
+                        trace.report(Errors.CYCLIC_GENERIC_UPPER_BOUND.on(typeParameter));
+                        return null;
+                    }
+                },
+                supertypeLoopsResolver
+                );
         trace.record(BindingContext.TYPE_PARAMETER, typeParameter, typeParameterDescriptor);
         extensibleScope.addClassifierDescriptor(typeParameterDescriptor);
         return typeParameterDescriptor;
@@ -461,20 +470,6 @@ public class DescriptorResolver {
         }
     }
 
-    public KotlinType resolveTypeParameterExtendsBound(
-            @NotNull TypeParameterDescriptor typeParameterDescriptor,
-            @NotNull KtTypeReference extendsBound,
-            LexicalScope scope,
-            BindingTrace trace
-    ) {
-        KotlinType type = typeResolver.resolveType(scope, extendsBound, trace, false);
-        if (type.getConstructor().equals(typeParameterDescriptor.getTypeConstructor())) {
-            trace.report(Errors.CYCLIC_GENERIC_UPPER_BOUND.on(extendsBound));
-            type = ErrorUtils.createErrorType("Cyclic upper bound: " + type);
-        }
-        return type;
-    }
-
     public void resolveGenericBounds(
             @NotNull KtTypeParameterListOwner declaration,
             @NotNull DeclarationDescriptor descriptor,
@@ -494,7 +489,7 @@ public class DescriptorResolver {
 
             KtTypeReference extendsBound = jetTypeParameter.getExtendsBound();
             if (extendsBound != null) {
-                KotlinType type = resolveTypeParameterExtendsBound(typeParameterDescriptor, extendsBound, scope, trace);
+                KotlinType type = typeResolver.resolveType(scope, extendsBound, trace, false);
                 typeParameterDescriptor.addUpperBound(type);
                 deferredUpperBoundCheckerTasks.add(new UpperBoundCheckerTask(extendsBound, type));
             }
@@ -523,9 +518,10 @@ public class DescriptorResolver {
 
         for (TypeParameterDescriptorImpl parameter : parameters) {
             parameter.addDefaultUpperBound();
-
             parameter.setInitialized();
+        }
 
+        for (TypeParameterDescriptorImpl parameter : parameters) {
             checkConflictingUpperBounds(trace, parameter, typeParameters.get(parameter.getIndex()));
         }
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyTypeParameterDescriptor.java

@@ -18,7 +18,9 @@ package org.jetbrains.kotlin.resolve.lazy.descriptors;
 
 import kotlin.CollectionsKt;
 import org.jetbrains.annotations.NotNull;
+import org.jetbrains.kotlin.descriptors.SupertypeLoopChecker;
 import org.jetbrains.kotlin.descriptors.impl.AbstractLazyTypeParameterDescriptor;
+import org.jetbrains.kotlin.diagnostics.Errors;
 import org.jetbrains.kotlin.lexer.KtTokens;
 import org.jetbrains.kotlin.psi.*;
 import org.jetbrains.kotlin.resolve.BindingContext;
@@ -58,6 +60,22 @@ public class LazyTypeParameterDescriptor extends AbstractLazyTypeParameterDescri
         this.c.getTrace().record(BindingContext.TYPE_PARAMETER, typeParameter, this);
     }
 
+    @NotNull
+    @Override
+    protected SupertypeLoopChecker getSupertypeLoopChecker() {
+        return c.getSupertypeLoopChecker();
+    }
+
+    @Override
+    protected void reportCycleError(@NotNull KotlinType type) {
+        for (KtTypeReference typeReference : getAllUpperBounds()) {
+            if (resolveBoundType(typeReference).getConstructor().equals(type.getConstructor())) {
+                c.getTrace().report(Errors.CYCLIC_GENERIC_UPPER_BOUND.on(typeReference));
+                return;
+            }
+        }
+    }
+
     @NotNull
     @Override
     protected List<KotlinType> resolveUpperBounds() {

compiler/testData/diagnostics/tests/generics/cyclicBounds/functions.kt

@@ -0,0 +1,7 @@
+fun <<!CYCLIC_GENERIC_UPPER_BOUND!>T : F?<!>, F : T?> foo1() {}
+
+fun <T : F?, <!CYCLIC_GENERIC_UPPER_BOUND!>F : E<!>, E : F?> foo2() {}
+
+fun <<!CYCLIC_GENERIC_UPPER_BOUND!>T<!>, F> foo3() where T : F?, F : T {}
+
+fun <T, <!CYCLIC_GENERIC_UPPER_BOUND!>F<!>, E> foo4() where T : F?, F : E, E : F? {}

compiler/testData/diagnostics/tests/generics/cyclicBounds/functions.txt

@@ -0,0 +1,6 @@
+package
+
+public fun </*0*/ T : [ERROR : Cyclic upper bounds], /*1*/ F : T?> foo1(): kotlin.Unit
+public fun </*0*/ T : F?, /*1*/ F : [ERROR : Cyclic upper bounds], /*2*/ E : F?> foo2(): kotlin.Unit
+public fun </*0*/ T : [ERROR : Cyclic upper bounds], /*1*/ F : T> foo3(): kotlin.Unit
+public fun </*0*/ T : F?, /*1*/ F : [ERROR : Cyclic upper bounds], /*2*/ E : F?> foo4(): kotlin.Unit

compiler/testData/diagnostics/tests/generics/cyclicBounds/inClass.kt

@@ -0,0 +1,7 @@
+class A1<T : <!CYCLIC_GENERIC_UPPER_BOUND!>F?<!>, F : <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>>
+
+class A2<T : F?, F : <!CYCLIC_GENERIC_UPPER_BOUND!>E<!>, E : <!CYCLIC_GENERIC_UPPER_BOUND!>F?<!>>
+
+class A3<T, F> where T : <!CYCLIC_GENERIC_UPPER_BOUND!>F?<!>, F : <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>
+
+class A4<T, F, E> where T : F?, F : <!CYCLIC_GENERIC_UPPER_BOUND!>E<!>, E : <!CYCLIC_GENERIC_UPPER_BOUND!>F<!>

compiler/testData/diagnostics/tests/generics/cyclicBounds/inClass.txt

@@ -0,0 +1,29 @@
+package
+
+public final class A1</*0*/ T : [ERROR : Cyclic upper bounds], /*1*/ F : [ERROR : Cyclic upper bounds]> {
+    public constructor A1</*0*/ T : [ERROR : Cyclic upper bounds], /*1*/ F : [ERROR : Cyclic upper bounds]>()
+    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 final class A2</*0*/ T : F?, /*1*/ F : [ERROR : Cyclic upper bounds], /*2*/ E : [ERROR : Cyclic upper bounds]> {
+    public constructor A2</*0*/ T : F?, /*1*/ F : [ERROR : Cyclic upper bounds], /*2*/ E : [ERROR : Cyclic upper bounds]>()
+    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 final class A3</*0*/ T : [ERROR : Cyclic upper bounds], /*1*/ F : [ERROR : Cyclic upper bounds]> {
+    public constructor A3</*0*/ T : [ERROR : Cyclic upper bounds], /*1*/ F : [ERROR : Cyclic upper bounds]>()
+    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 final class A4</*0*/ T : F?, /*1*/ F : [ERROR : Cyclic upper bounds], /*2*/ E : [ERROR : Cyclic upper bounds]> {
+    public constructor A4</*0*/ T : F?, /*1*/ F : [ERROR : Cyclic upper bounds], /*2*/ E : [ERROR : Cyclic upper bounds]>()
+    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/testData/diagnostics/tests/j+k/recursiveRawUpperBound2.kt

@@ -0,0 +1,8 @@
+// FILE: XYZ.java
+public interface XYZ<X extends X> {
+    XYZ foo() {}
+}
+
+// FILE: main.kt
+
+fun main(xyz: XYZ<*>) = xyz.foo()

compiler/testData/diagnostics/tests/j+k/recursiveRawUpperBound2.txt

@@ -0,0 +1,11 @@
+package
+
+public /*synthesized*/ fun </*0*/ X : [ERROR : Cyclic upper bounds]> XYZ(/*0*/ function: () -> XYZ<(raw) [ERROR : Cyclic upper bounds]>!): XYZ<X>
+public fun main(/*0*/ xyz: XYZ<*>): XYZ<(raw) [ERROR : Cyclic upper bounds]>!
+
+public interface XYZ</*0*/ X : [ERROR : Cyclic upper bounds]> {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): XYZ<(raw) [ERROR : Cyclic upper bounds]>!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/j+k/recursiveRawUpperBound3.kt

@@ -0,0 +1,8 @@
+// FILE: XYZ.java
+public interface XYZ<X extends Y, Y extends Z, Z extends Y> {
+    XYZ foo() {}
+}
+
+// FILE: main.kt
+
+fun main(xyz: XYZ<*, *, *>) = xyz.foo()

compiler/testData/diagnostics/tests/j+k/recursiveRawUpperBound3.txt

@@ -0,0 +1,11 @@
+package
+
+public /*synthesized*/ fun </*0*/ X : Y!, /*1*/ Y : [ERROR : Cyclic upper bounds], /*2*/ Z : [ERROR : Cyclic upper bounds]> XYZ(/*0*/ function: () -> XYZ<(raw) [ERROR : Cyclic upper bounds], (raw) [ERROR : Cyclic upper bounds], (raw) [ERROR : Cyclic upper bounds]>!): XYZ<X, Y, Z>
+public fun main(/*0*/ xyz: XYZ<*, *, *>): XYZ<(raw) [ERROR : Cyclic upper bounds], (raw) [ERROR : Cyclic upper bounds], (raw) [ERROR : Cyclic upper bounds]>!
+
+public interface XYZ</*0*/ X : Y!, /*1*/ Y : [ERROR : Cyclic upper bounds], /*2*/ Z : [ERROR : Cyclic upper bounds]> {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): XYZ<(raw) [ERROR : Cyclic upper bounds], (raw) [ERROR : Cyclic upper bounds], (raw) [ERROR : Cyclic upper bounds]>!
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/regressions/itselfAsUpperBound.kt

@@ -1,3 +1,3 @@
 // !DIAGNOSTICS: -MUST_BE_INITIALIZED -TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER
-fun <T: <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>> foo() {}
-val <T: <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>> prop
+fun <<!CYCLIC_GENERIC_UPPER_BOUND!>T: T?<!>> foo() {}
+val <<!CYCLIC_GENERIC_UPPER_BOUND!>T: T?<!>> prop

compiler/testData/diagnostics/tests/regressions/itselfAsUpperBound.txt

@@ -1,4 +1,4 @@
 package
 
-public val </*0*/ T : [ERROR : Cyclic upper bound: T?]> prop: [ERROR : No type, no body]
-public fun </*0*/ T : [ERROR : Cyclic upper bound: T?]> foo(): kotlin.Unit
+public val </*0*/ T : [ERROR : Cyclic upper bounds]> prop: [ERROR : No type, no body]
+public fun </*0*/ T : [ERROR : Cyclic upper bounds]> foo(): kotlin.Unit

compiler/testData/diagnostics/tests/regressions/itselfAsUpperBoundInClass.txt

@@ -1,7 +1,7 @@
 package
 
-public final class MyClass</*0*/ T : [ERROR : Cyclic upper bound: T?]> {
-    public constructor MyClass</*0*/ T : [ERROR : Cyclic upper bound: T?]>()
+public final class MyClass</*0*/ T : [ERROR : Cyclic upper bounds]> {
+    public constructor MyClass</*0*/ T : [ERROR : Cyclic upper bounds]>()
     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/testData/diagnostics/tests/regressions/itselfAsUpperBoundInClassNotNull.txt

@@ -1,7 +1,7 @@
 package
 
-public final class MyClass</*0*/ T : [ERROR : Cyclic upper bound: T]> {
-    public constructor MyClass</*0*/ T : [ERROR : Cyclic upper bound: T]>()
+public final class MyClass</*0*/ T : [ERROR : Cyclic upper bounds]> {
+    public constructor MyClass</*0*/ T : [ERROR : Cyclic upper bounds]>()
     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/testData/diagnostics/tests/regressions/itselfAsUpperBoundLocal.kt

@@ -1,4 +1,4 @@
 fun bar() {
-    fun <T: <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>> foo() {}
+    fun <<!CYCLIC_GENERIC_UPPER_BOUND!>T: T?<!>> foo() {}
     <!TYPE_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>foo<!>()
 }

compiler/testData/diagnostics/tests/regressions/itselfAsUpperBoundMember.kt

@@ -1,5 +1,5 @@
 // !DIAGNOSTICS: -MUST_BE_INITIALIZED_OR_BE_ABSTRACT -TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER
 class My {
-    fun <T: <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>> foo() {}
-    val <T: <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>> prop: T
+    fun <<!CYCLIC_GENERIC_UPPER_BOUND!>T: T?<!>> foo() {}
+    val <<!CYCLIC_GENERIC_UPPER_BOUND!>T: T?<!>> prop: T
 }

compiler/testData/diagnostics/tests/regressions/itselfAsUpperBoundMember.txt

@@ -2,9 +2,9 @@ package
 
 public final class My {
     public constructor My()
-    public final val </*0*/ T : [ERROR : Cyclic upper bound: T?]> prop: [ERROR : ?]
+    public final val </*0*/ T : [ERROR : Cyclic upper bounds]> prop: [ERROR : ?]
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public final fun </*0*/ T : [ERROR : Cyclic upper bound: T?]> foo(): kotlin.Unit
+    public final fun </*0*/ T : [ERROR : Cyclic upper bounds]> foo(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }

compiler/testData/diagnostics/tests/regressions/itselfAsUpperBoundNotNull.kt

@@ -1,3 +1,3 @@
 // !DIAGNOSTICS: -MUST_BE_INITIALIZED -TYPE_PARAMETER_OF_PROPERTY_NOT_USED_IN_RECEIVER
-fun <T: <!CYCLIC_GENERIC_UPPER_BOUND!>T<!>> foo() {}
-val <T: <!CYCLIC_GENERIC_UPPER_BOUND!>T?<!>> prop: T
+fun <<!CYCLIC_GENERIC_UPPER_BOUND!>T: T<!>> foo() {}
+val <<!CYCLIC_GENERIC_UPPER_BOUND!>T: T?<!>> prop: T

compiler/testData/diagnostics/tests/regressions/itselfAsUpperBoundNotNull.txt

@@ -1,4 +1,4 @@
 package
 
-public val </*0*/ T : [ERROR : Cyclic upper bound: T?]> prop: [ERROR : ?]
-public fun </*0*/ T : [ERROR : Cyclic upper bound: T]> foo(): kotlin.Unit
+public val </*0*/ T : [ERROR : Cyclic upper bounds]> prop: [ERROR : ?]
+public fun </*0*/ T : [ERROR : Cyclic upper bounds]> foo(): kotlin.Unit

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

@@ -6618,6 +6618,27 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("compiler/testData/diagnostics/tests/generics/cyclicBounds")
+            @TestDataPath("$PROJECT_ROOT")
+            @RunWith(JUnit3RunnerWithInners.class)
+            public static class CyclicBounds extends AbstractJetDiagnosticsTest {
+                public void testAllFilesPresentInCyclicBounds() throws Exception {
+                    JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/diagnostics/tests/generics/cyclicBounds"), Pattern.compile("^(.+)\\.kt$"), true);
+                }
+
+                @TestMetadata("functions.kt")
+                public void testFunctions() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/generics/cyclicBounds/functions.kt");
+                    doTest(fileName);
+                }
+
+                @TestMetadata("inClass.kt")
+                public void testInClass() throws Exception {
+                    String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/generics/cyclicBounds/inClass.kt");
+                    doTest(fileName);
+                }
+            }
+
             @TestMetadata("compiler/testData/diagnostics/tests/generics/nullability")
             @TestDataPath("$PROJECT_ROOT")
             @RunWith(JUnit3RunnerWithInners.class)
@@ -9252,6 +9273,18 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
 
+            @TestMetadata("recursiveRawUpperBound2.kt")
+            public void testRecursiveRawUpperBound2() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/j+k/recursiveRawUpperBound2.kt");
+                doTest(fileName);
+            }
+
+            @TestMetadata("recursiveRawUpperBound3.kt")
+            public void testRecursiveRawUpperBound3() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/j+k/recursiveRawUpperBound3.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("samInConstructorWithGenerics.kt")
             public void testSamInConstructorWithGenerics() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/j+k/samInConstructorWithGenerics.kt");