Do not consider fake variables for objects in :: resolution

The main change is in
NewResolutionOldInference.ResolutionKind.CallableReference, where
createVariableProcessor creates a processor which no longer lists objects

 #KT-12322 Fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/NewResolutionOldInference.kt

@@ -75,17 +75,16 @@ class NewResolutionOldInference(
                 val invokeContext = outer.InvokeContext(scopeTower, name, context, tracing)
                 return outer.createFunctionTowerProcessor(invokeContext, explicitReceiver)
             }
-
         }
+
         object Variable : ResolutionKind<VariableDescriptor>() {
             override fun createTowerProcessor(
                     outer: NewResolutionOldInference, name: Name, tracing: TracingStrategy,
                     scopeTower: ScopeTower, explicitReceiver: Receiver?, context: BasicCallResolutionContext
             ): ScopeTowerProcessor<MyCandidate<VariableDescriptor>> {
                 val simpleContext = outer.SimpleContext<VariableDescriptor>(scopeTower, name, context, tracing)
-                return createVariableProcessor(simpleContext, explicitReceiver)
+                return createVariableAndObjectProcessor(simpleContext, explicitReceiver)
             }
-
         }
 
         object CallableReference : ResolutionKind<CallableDescriptor>() {

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/tower/InvokeProcessors.kt

@@ -90,7 +90,7 @@ class InvokeTowerProcessor<F : Candidate<FunctionDescriptor>, V : Candidate<Vari
         explicitReceiver: Receiver?
 ) : AbstractInvokeTowerProcessor<F, V>(
         invokeContext,
-        createVariableProcessor(invokeContext.contextForVariable(stripExplicitReceiver = false), explicitReceiver)
+        createVariableAndObjectProcessor(invokeContext.contextForVariable(stripExplicitReceiver = false), explicitReceiver)
 ) {
 
     // todo filter by operator
@@ -106,7 +106,7 @@ class InvokeExtensionTowerProcessor<F : Candidate<FunctionDescriptor>, V : Candi
         private val explicitReceiver: ReceiverValue?
 ) : AbstractInvokeTowerProcessor<F, V>(
         invokeContext,
-        createVariableProcessor(invokeContext.contextForVariable(stripExplicitReceiver = true), explicitReceiver = null)
+        createVariableAndObjectProcessor(invokeContext.contextForVariable(stripExplicitReceiver = true), explicitReceiver = null)
 ) {
 
     override fun createInvokeProcessor(variableCandidate: V): ScopeTowerProcessor<F> {

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/tower/ScopeTower.kt

@@ -58,6 +58,8 @@ interface DataFlowDecorator {
 interface ScopeTowerLevel {
     fun getVariables(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<VariableDescriptor>>
 
+    fun getObjects(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<VariableDescriptor>>
+
     fun getFunctions(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<FunctionDescriptor>>
 }
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/tower/ScopeTowerProcessors.kt

@@ -139,5 +139,11 @@ private fun <D : CallableDescriptor, C: Candidate<D>> createSimpleProcessor(
 fun <C : Candidate<VariableDescriptor>> createVariableProcessor(context: TowerContext<VariableDescriptor, C>, explicitReceiver: Receiver?)
         = createSimpleProcessor(context, explicitReceiver, ScopeTowerLevel::getVariables)
 
+fun <C : Candidate<VariableDescriptor>> createVariableAndObjectProcessor(context: TowerContext<VariableDescriptor, C>, explicitReceiver: Receiver?) =
+        CompositeScopeTowerProcessor(
+                createVariableProcessor(context, explicitReceiver),
+                createSimpleProcessor(context, explicitReceiver, ScopeTowerLevel::getObjects)
+        )
+
 fun <C : Candidate<FunctionDescriptor>> createFunctionProcessor(context: TowerContext<FunctionDescriptor, C>, explicitReceiver: Receiver?)
         = createSimpleProcessor(context, explicitReceiver, ScopeTowerLevel::getFunctions)

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/tower/TowerLevels.kt

@@ -138,6 +138,10 @@ internal class ReceiverScopeTowerLevel(
         return collectMembers { getContributedVariables(name, location) }
     }
 
+    override fun getObjects(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<VariableDescriptor>> {
+        return emptyList()
+    }
+
     override fun getFunctions(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<FunctionDescriptor>> {
         return collectMembers {
             getContributedFunctions(name, location) + it.getInnerConstructors(name, location)
@@ -147,7 +151,12 @@ internal class ReceiverScopeTowerLevel(
 
 internal class QualifierScopeTowerLevel(scopeTower: ScopeTower, val qualifier: QualifierReceiver) : AbstractScopeTowerLevel(scopeTower) {
     override fun getVariables(name: Name, extensionReceiver: ReceiverValue?) = qualifier.staticScope
-            .getContributedVariablesAndObjects(name, location).map {
+            .getContributedVariables(name, location).map {
+                createCandidateDescriptor(it, dispatchReceiver = null)
+            }
+
+    override fun getObjects(name: Name, extensionReceiver: ReceiverValue?) = qualifier.staticScope
+            .getContributedObjectVariables(name, location).map {
                 createCandidateDescriptor(it, dispatchReceiver = null)
             }
 
@@ -166,7 +175,12 @@ internal open class ScopeBasedTowerLevel protected constructor(
     internal constructor(scopeTower: ScopeTower, lexicalScope: LexicalScope): this(scopeTower, lexicalScope as ResolutionScope)
 
     override fun getVariables(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<VariableDescriptor>>
-            = resolutionScope.getContributedVariablesAndObjects(name, location).map {
+            = resolutionScope.getContributedVariables(name, location).map {
+                createCandidateDescriptor(it, dispatchReceiver = null)
+            }
+
+    override fun getObjects(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<VariableDescriptor>>
+            = resolutionScope.getContributedObjectVariables(name, location).map {
                 createCandidateDescriptor(it, dispatchReceiver = null)
             }
 
@@ -184,7 +198,6 @@ internal class SyntheticScopeBasedTowerLevel(
         scopeTower: ScopeTower,
         private val syntheticScopes: SyntheticScopes
 ): AbstractScopeTowerLevel(scopeTower) {
-
     override fun getVariables(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<VariableDescriptor>> {
         if (extensionReceiver == null) return emptyList()
 
@@ -194,6 +207,9 @@ internal class SyntheticScopeBasedTowerLevel(
         }
     }
 
+    override fun getObjects(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<VariableDescriptor>>
+            = emptyList()
+
     override fun getFunctions(name: Name, extensionReceiver: ReceiverValue?): Collection<CandidateWithBoundDispatchReceiver<FunctionDescriptor>> {
         if (extensionReceiver == null) return emptyList()
 
@@ -208,6 +224,9 @@ internal class HidesMembersTowerLevel(scopeTower: ScopeTower): AbstractScopeTowe
     override fun getVariables(name: Name, extensionReceiver: ReceiverValue?)
             = getCandidates(name, extensionReceiver, LexicalScope::collectVariables)
 
+    override fun getObjects(name: Name, extensionReceiver: ReceiverValue?)
+            = emptyList<CandidateWithBoundDispatchReceiver<VariableDescriptor>>()
+
     override fun getFunctions(name: Name, extensionReceiver: ReceiverValue?)
             = getCandidates(name, extensionReceiver, LexicalScope::collectFunctions)
 
@@ -247,10 +266,9 @@ private fun ResolutionScope.getContributedFunctionsAndConstructors(name: Name, l
            (classifier?.getTypeAliasConstructors() ?: emptyList())
 }
 
-private fun ResolutionScope.getContributedVariablesAndObjects(name: Name, location: LookupLocation): Collection<VariableDescriptor> {
+private fun ResolutionScope.getContributedObjectVariables(name: Name, location: LookupLocation): Collection<VariableDescriptor> {
     val objectDescriptor = getFakeDescriptorForObject(getContributedClassifier(name, location))
-
+    return listOfNotNull(objectDescriptor)
-    return getContributedVariables(name, location) + listOfNotNull(objectDescriptor)
 }
 
 private fun getFakeDescriptorForObject(classifier: ClassifierDescriptor?): FakeCallableDescriptorForObject? =

compiler/testData/diagnostics/tests/callableReference/resolve/noFakeDescriptorForObject.kt

@@ -0,0 +1,11 @@
+// !CHECK_TYPE
+// KT-12322 Overload resolution ambiguity with constructor references when class has a companion object
+
+class Foo {
+    companion object
+}
+
+fun test() {
+    val a = ::Foo
+    checkSubtype<() -> Foo>(a)
+}

compiler/testData/diagnostics/tests/callableReference/resolve/noFakeDescriptorForObject.txt

@@ -0,0 +1,17 @@
+package
+
+public fun test(): kotlin.Unit
+
+public final class Foo {
+    public constructor Foo()
+    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 companion object Companion {
+        private constructor Companion()
+        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

@@ -2291,6 +2291,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("noFakeDescriptorForObject.kt")
+                public void testNoFakeDescriptorForObject() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/callableReference/resolve/noFakeDescriptorForObject.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("overloads.kt")
                 public void testOverloads() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/callableReference/resolve/overloads.kt");

jps-plugin/testData/incremental/lookupTracker/classifierMembers/usages.kt

@@ -12,13 +12,13 @@ import bar.*
     /*p:foo*/A./*c:foo.A*/B./*c:foo.A.B c:foo.A.B.CO*/bar(1)
     /*p:foo*/A./*c:foo.A*/B./*c:foo.A.B*/CO./*c:foo.A.B.CO*/bar(1)
     /*p:foo c:foo.A(Companion)*/A
-    /*p:foo p:kotlin(Int)*/A./*c:foo.A c:foo.A.Companion*/a
+    /*p:foo p:kotlin(Int)*/A./*c:foo.A.Companion c:foo.A*/a
     /*p:foo*/A./*c:foo.A c:foo.A.Companion*/baz()
-    /*p:foo c:foo.A(Companion)*/A./*c:foo.A c:foo.A.Companion*/Companion
+    /*p:foo c:foo.A(Companion)*/A./*c:foo.A.Companion c:foo.A*/Companion
     /*p:foo*/A./*c:foo.A*/Companion./*c:foo.A.Companion*/baz()
-    /*p:foo c:foo.A(O)*/A./*c:foo.A c:foo.A.Companion*/O
+    /*p:foo c:foo.A(O)*/A./*c:foo.A.Companion c:foo.A*/O
     /*p:foo p:kotlin(String)*/A./*c:foo.A*/O./*c:foo.A.O*/v = /*p:kotlin(String)*/"OK"
-    /*p:foo*/A./*c:foo.A c:foo.A.Companion c:foo.A.Companion(getVala) c:foo.A.Companion(getVALA) p:foo p:bar p:java.lang p:kotlin p:kotlin.annotation p:kotlin.jvm p:kotlin.collections p:kotlin.coroutines p:kotlin.ranges p:kotlin.sequences p:kotlin.text p:kotlin.io*/vala
+    /*p:foo*/A./*c:foo.A.Companion c:foo.A c:foo.A.Companion(getVala) c:foo.A.Companion(getVALA) p:foo p:bar p:java.lang p:kotlin p:kotlin.annotation p:kotlin.jvm p:kotlin.collections p:kotlin.coroutines p:kotlin.ranges p:kotlin.sequences p:kotlin.text p:kotlin.io*/vala
     /*p:foo*/A./*c:foo.A c:foo.A.Companion c:foo.A.Companion(getVara) c:foo.A.Companion(getVARA) p:foo p:bar p:java.lang p:kotlin p:kotlin.annotation p:kotlin.jvm p:kotlin.collections p:kotlin.coroutines p:kotlin.ranges p:kotlin.sequences p:kotlin.text p:kotlin.io*/vara()
 
     /*p:foo(I) p:kotlin(Int)*/i./*c:foo.I*/a = /*p:kotlin(Int)*/2