FIR: handle imported members from objects more correctly

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/TowerLevels.kt

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.fir.resolve.transformers.ReturnTypeCalculatorWithJum
 import org.jetbrains.kotlin.fir.scopes.FirPosition
 import org.jetbrains.kotlin.fir.scopes.FirScope
 import org.jetbrains.kotlin.fir.scopes.ProcessorAction
+import org.jetbrains.kotlin.fir.scopes.impl.FirAbstractImportingScope
 import org.jetbrains.kotlin.fir.scopes.impl.FirExplicitSimpleImportingScope
 import org.jetbrains.kotlin.fir.scopes.processClassifiersByNameWithAction
 import org.jetbrains.kotlin.fir.service
@@ -144,7 +145,7 @@ class MemberScopeTowerLevel(
 // We can access here members of currently accessible scope which is not influenced by explicit receiver
 // We can either have no explicit receiver at all, or it can be an extension receiver
 // An explicit receiver never can be a dispatch receiver at this level
-// So: dispatch receiver = strictly NONE
+// So: dispatch receiver = strictly none (EXCEPTION: importing scopes with import from objects)
 // So: extension receiver = either none or explicit
 // (if explicit receiver exists, it always *should* be an extension receiver)
 class ScopeTowerLevel(
@@ -152,6 +153,9 @@ class ScopeTowerLevel(
     val scope: FirScope,
     val implicitExtensionReceiver: ImplicitReceiverValue? = null
 ) : SessionBasedTowerLevel(session) {
+    private fun FirCallableSymbol<*>.hasConsistentReceivers(extensionReceiver: ReceiverValue?): Boolean =
+        hasConsistentExtensionReceiver(extensionReceiver) && (scope is FirAbstractImportingScope || dispatchReceiverValue() == null)
+
     override fun <T : AbstractFirBasedSymbol<*>> processElementsByName(
         token: TowerScopeLevel.Token<T>,
         name: Name,
@@ -165,7 +169,7 @@ class ScopeTowerLevel(
         @Suppress("UNCHECKED_CAST")
         return when (token) {
             TowerScopeLevel.Token.Properties -> scope.processPropertiesByName(name) { candidate ->
-                if (candidate.hasConsistentExtensionReceiver(extensionReceiver) && candidate.dispatchReceiverValue() == null) {
+                if (candidate.hasConsistentReceivers(extensionReceiver)) {
                     processor.consumeCandidate(
                         candidate as T, dispatchReceiverValue = null,
                         implicitExtensionReceiverValue = implicitExtensionReceiver
@@ -175,7 +179,7 @@ class ScopeTowerLevel(
                 }
             }
             TowerScopeLevel.Token.Functions -> scope.processFunctionsByName(name) { candidate ->
-                if (candidate.hasConsistentExtensionReceiver(extensionReceiver) && candidate.dispatchReceiverValue() == null) {
+                if (candidate.hasConsistentReceivers(extensionReceiver)) {
                     processor.consumeCandidate(
                         candidate as T, dispatchReceiverValue = null,
                         implicitExtensionReceiverValue = implicitExtensionReceiver
@@ -240,7 +244,7 @@ fun FirCallableDeclaration<*>.dispatchReceiverValue(session: FirSession): ClassD
     val symbol = session.service<FirSymbolProvider>().getClassLikeSymbolByFqName(id) as? FirClassSymbol ?: return null
     val regularClass = symbol.fir
 
-    // TODO: this is also not true, but objects can be also imported
+    // TODO: this is also not true, but objects can be also imported, companions can be also used implicitly
     if (regularClass.classKind == ClassKind.OBJECT) return null
 
     return ClassDispatchReceiverValue(regularClass.symbol)

compiler/fir/resolve/testData/resolve/expresssions/importedReceiver.kt

@@ -0,0 +1,31 @@
+import My.bar
+import My.baz
+import My.gau
+import My.wat
+import My.watwat
+
+fun <T> T.foo() {}
+
+interface Your<R> {
+    fun wat() {}
+    fun <T> T.watwat() {}
+}
+
+object My : Your<Double> {
+    fun <T> T.bar() {}
+    fun baz()
+    fun Boolean.gau() {}
+}
+
+fun test() {
+    42.foo()
+    "".foo()
+
+    42.bar()
+    "".bar()
+
+    baz()
+    true.gau()
+    wat()
+    false.watwat()
+}

compiler/fir/resolve/testData/resolve/expresssions/importedReceiver.txt

@@ -0,0 +1,35 @@
+FILE: importedReceiver.kt
+    public final fun <T> R|T|.foo(): R|kotlin/Unit| {
+    }
+    public abstract interface Your<R> : R|kotlin/Any| {
+        public open fun wat(): R|kotlin/Unit| {
+        }
+
+        public open fun <T> R|T|.watwat(): R|kotlin/Unit| {
+        }
+
+    }
+    public final object My : R|Your<kotlin/Double>| {
+        private constructor(): R|My| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final fun <T> R|T|.bar(): R|kotlin/Unit| {
+        }
+
+        public final fun baz(): R|kotlin/Unit|
+
+        public final fun R|kotlin/Boolean|.gau(): R|kotlin/Unit| {
+        }
+
+    }
+    public final fun test(): R|kotlin/Unit| {
+        Int(42).R|/foo|<R|kotlin/Int|>()
+        String().R|/foo|<R|kotlin/String|>()
+        Int(42).R|/My.bar|<R|kotlin/Int|>()
+        String().R|/My.bar|<R|kotlin/String|>()
+        R|/My.baz|()
+        Boolean(true).R|/My.gau|()
+        R|FakeOverride</Your.wat: R|kotlin/Unit|>|()
+        Boolean(false).<Inapplicable(WRONG_RECEIVER): [/Your.watwat]>#()
+    }

compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirResolveTestCaseGenerated.java

@@ -282,6 +282,11 @@ public class FirResolveTestCaseGenerated extends AbstractFirResolveTestCase {
             runTest("compiler/fir/resolve/testData/resolve/expresssions/dispatchReceiver.kt");
         }
 
+        @TestMetadata("importedReceiver.kt")
+        public void testImportedReceiver() throws Exception {
+            runTest("compiler/fir/resolve/testData/resolve/expresssions/importedReceiver.kt");
+        }
+
         @TestMetadata("lambda.kt")
         public void testLambda() throws Exception {
             runTest("compiler/fir/resolve/testData/resolve/expresssions/lambda.kt");

compiler/testData/ir/irText/expressions/useImportedMember.fir.txt

@@ -220,7 +220,7 @@ FILE fqName:<root> fileName:/useImportedMember.kt
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
-              arg0: ERROR_CALL 'Unresolved reference: <Unresolved name: fromInterface>#' type=IrErrorType
+              arg0: ERROR_CALL 'Unresolved reference: <Inapplicable(WRONG_RECEIVER): [/I.fromInterface]>#' type=IrErrorType
               arg1: CONST Int type=kotlin.Int value=9
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="9"
@@ -237,8 +237,8 @@ FILE fqName:<root> fileName:/useImportedMember.kt
         BRANCH
           if: CALL 'public final fun not (): kotlin.Boolean declared in kotlin.Boolean' type=kotlin.Boolean origin=EXCLEQ
             $this: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EXCLEQ
-              arg0: ERROR_CALL 'Unresolved reference: <Unresolved name: genericFromSuper>#' type=IrErrorType
+              arg0: CALL 'public open fun genericFromSuper (g: kotlin.String): kotlin.String declared in <root>.I' type=kotlin.String origin=null
-                CONST String type=kotlin.String value="11"
+                g: CONST String type=kotlin.String value="11"
               arg1: CONST String type=kotlin.String value="11"
           then: RETURN type=kotlin.Nothing from='public final fun box (): kotlin.String declared in <root>'
             CONST String type=kotlin.String value="11"