[FIR] Fix generating fir for invoke calls

compiler/fir/lightTree/src/org/jetbrains/kotlin/fir/lightTree/converter/ExpressionsConverter.kt

@@ -448,7 +448,7 @@ class ExpressionsConverter(
             this.calleeReference = when {
                 name != null -> FirSimpleNamedReference(null, name.nameAsSafeName(), null)
                 additionalArgument != null -> {
-                    arguments += additionalArgument!!
+                    explicitReceiver = additionalArgument!!
                     FirSimpleNamedReference(null, OperatorNameConventions.INVOKE, null)
                 }
                 else -> FirErrorNamedReferenceImpl(null, FirSimpleDiagnostic("Call has no callee", DiagnosticKind.Syntax))

compiler/fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt

@@ -1242,7 +1242,7 @@ class RawFirBuilder(session: FirSession, val stubMode: Boolean) : BaseFirBuilder
                         null, FirSimpleDiagnostic("Call has no callee", DiagnosticKind.Syntax)
                     )
                     else -> {
-                        arguments += calleeExpression.toFirExpression("Incorrect invoke receiver")
+                        explicitReceiver = calleeExpression.toFirExpression("Incorrect invoke receiver")
                         FirSimpleNamedReference(
                             source, OperatorNameConventions.INVOKE, null
                         )

compiler/fir/psi2fir/testData/rawBuilder/expressions/calls.txt

@@ -30,7 +30,7 @@ FILE: calls.kt
 
     }
     public? final? fun testInvoke(): Int {
-        ^testInvoke invoke#(My#(Int(13)))
+        ^testInvoke My#(Int(13)).invoke#()
     }
     public? final? fun testQualified(first: My, second: My?): R|kotlin/Unit| {
         println#(first#.x#)

compiler/fir/resolve/testData/resolve/arguments/invoke.kt

@@ -0,0 +1,9 @@
+class My(var x: Int) {
+    operator fun invoke() = x
+
+    fun foo() {}
+
+    fun copy() = My(x)
+}
+
+fun testInvoke(): Int = My(13)()

compiler/fir/resolve/testData/resolve/arguments/invoke.txt

@@ -0,0 +1,25 @@
+FILE: invoke.kt
+    public final class My : R|kotlin/Any| {
+        public constructor(x: R|kotlin/Int|): R|My| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final var x: R|kotlin/Int| = R|<local>/x|
+            public get(): R|kotlin/Int|
+            public set(value: R|kotlin/Int|): R|kotlin/Unit|
+
+        public final operator fun invoke(): R|kotlin/Int| {
+            ^invoke this@R|/My|.R|/My.x|
+        }
+
+        public final fun foo(): R|kotlin/Unit| {
+        }
+
+        public final fun copy(): R|My| {
+            ^copy R|/My.My|(this@R|/My|.R|/My.x|)
+        }
+
+    }
+    public final fun testInvoke(): R|kotlin/Int| {
+        ^testInvoke R|/My.My|(Int(13)).R|/My.invoke|()
+    }

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

@@ -230,6 +230,11 @@ public class FirDiagnosticsTestGenerated extends AbstractFirDiagnosticsTest {
             runTest("compiler/fir/resolve/testData/resolve/arguments/default.kt");
         }
 
+        @TestMetadata("invoke.kt")
+        public void testInvoke() throws Exception {
+            runTest("compiler/fir/resolve/testData/resolve/arguments/invoke.kt");
+        }
+
         @TestMetadata("lambda.kt")
         public void testLambda() throws Exception {
             runTest("compiler/fir/resolve/testData/resolve/arguments/lambda.kt");

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

@@ -18,11 +18,11 @@ FILE fqName:<root> fileName:/variableAsFunctionCall.kt
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun test2 (f: kotlin.Function1<kotlin.String, kotlin.Unit>): IrErrorType declared in <root>'
         ERROR_CALL 'Unresolved reference: <Unresolved name: f>#' type=IrErrorType
-  FUN name:test3 visibility:public modality:FINAL <> () returnType:IrErrorType
+  FUN name:test3 visibility:public modality:FINAL <> () returnType:kotlin.String
     BLOCK_BODY
-      RETURN type=kotlin.Nothing from='public final fun test3 (): IrErrorType declared in <root>'
-        ERROR_CALL 'Unresolved reference: <Unresolved name: invoke>#' type=IrErrorType
-          CALL 'public final fun k (): kotlin.Function0<kotlin.String> declared in <root>' type=kotlin.Function0<kotlin.String> origin=null
+      RETURN type=kotlin.Nothing from='public final fun test3 (): kotlin.String declared in <root>'
+        CALL 'public abstract fun invoke (): kotlin.String declared in kotlin.Function0' type=kotlin.String origin=null
+          $this: CALL 'public final fun k (): kotlin.Function0<kotlin.String> declared in <root>' type=kotlin.Function0<kotlin.String> origin=null
             $receiver: CONST String type=kotlin.String value="hello"
   FUN name:test4 visibility:public modality:FINAL <> (ns:kotlin.String?) returnType:kotlin.String?
     VALUE_PARAMETER name:ns index:0 type:kotlin.String?