FIR IDE: resolve implicit invoke to callable property

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/references/FirReferenceResolveHelper.kt

@@ -6,6 +6,11 @@
 package org.jetbrains.kotlin.idea.references
 
 import com.intellij.psi.tree.TokenSet
+import org.jetbrains.kotlin.analysis.api.fir.*
+import org.jetbrains.kotlin.analysis.api.fir.symbols.KtFirPackageSymbol
+import org.jetbrains.kotlin.analysis.api.symbols.KtSymbol
+import org.jetbrains.kotlin.analysis.low.level.api.fir.api.getOrBuildFir
+import org.jetbrains.kotlin.analysis.low.level.api.fir.api.getOrBuildFirSafe
 import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.declarations.*
 import org.jetbrains.kotlin.fir.declarations.builder.buildImport
@@ -26,13 +31,9 @@ import org.jetbrains.kotlin.fir.symbols.FirBasedSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.ConeClassLikeLookupTagImpl
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.analysis.api.fir.getCandidateSymbols
-import org.jetbrains.kotlin.analysis.low.level.api.fir.api.getOrBuildFir
-import org.jetbrains.kotlin.analysis.low.level.api.fir.api.getOrBuildFirSafe
 import org.jetbrains.kotlin.analysis.api.fir.KtFirAnalysisSession
 import org.jetbrains.kotlin.analysis.api.fir.KtSymbolByFirBuilder
 import org.jetbrains.kotlin.analysis.api.fir.buildSymbol
-import org.jetbrains.kotlin.analysis.api.fir.symbols.KtFirPackageSymbol
-import org.jetbrains.kotlin.analysis.api.symbols.KtSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirSyntheticPropertySymbol
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.name.ClassId
@@ -186,7 +187,7 @@ internal object FirReferenceResolveHelper {
             is FirErrorNamedReference -> getSymbolsByErrorNamedReference(fir, symbolBuilder)
             is FirVariableAssignment -> getSymbolsByVariableAssignment(fir, session, symbolBuilder)
             is FirResolvedNamedReference -> getSymbolByResolvedNameReference(fir, expression, analysisSession, session, symbolBuilder)
-            is FirResolvable -> getSymbolsByResolvable(fir, session, symbolBuilder)
+            is FirResolvable -> getSymbolsByResolvable(fir, expression, session, symbolBuilder)
             is FirNamedArgumentExpression -> getSymbolsByNameArgumentExpression(expression, analysisSession, symbolBuilder)
             else -> handleUnknownFirElement(expression, analysisSession, session, symbolBuilder)
         }
@@ -211,7 +212,7 @@ internal object FirReferenceResolveHelper {
         if (parentAsCall != null) {
             val firResolvable = parentAsCall.getOrBuildFirSafe<FirResolvable>(analysisSession.firResolveState)
             if (firResolvable != null) {
-                return getSymbolsByResolvable(firResolvable, session, symbolBuilder)
+                return getSymbolsByResolvable(firResolvable, expression, session, symbolBuilder)
             }
         }
         return fir.toTargetSymbol(session, symbolBuilder)
@@ -284,10 +285,23 @@ internal object FirReferenceResolveHelper {
 
     private fun getSymbolsByResolvable(
         fir: FirResolvable,
+        expression: KtSimpleNameExpression,
         session: FirSession,
         symbolBuilder: KtSymbolByFirBuilder
     ): Collection<KtSymbol> {
-        val calleeReference = fir.calleeReference
+        val calleeReference =
+            if (fir is FirFunctionCall &&
+                fir.isImplicitFunctionCall() &&
+                expression is KtNameReferenceExpression
+            ) {
+                // we are resolving implicit invoke call, like
+                // fun foo(a: () -> Unit) {
+                //     <expression>a</expression>()
+                // }
+                val receiver =
+                    fir.dispatchReceiver as? FirQualifiedAccessExpression ?: fir.extensionReceiver as FirQualifiedAccessExpression
+                receiver.calleeReference
+            } else fir.calleeReference
         return calleeReference.toTargetSymbol(session, symbolBuilder)
     }
 

analysis/analysis-api-fir/tests/org/jetbrains/kotlin/analysis/api/fir/FirReferenceResolveTestGenerated.java

@@ -216,6 +216,24 @@ public class FirReferenceResolveTestGenerated extends AbstractFirReferenceResolv
         runTest("analysis/analysis-api/testData/referenceResolve/GenericTypeInFunctionParameter.kt");
     }
 
+    @Test
+    @TestMetadata("implicitExtensionInvoke.kt")
+    public void testImplicitExtensionInvoke() throws Exception {
+        runTest("analysis/analysis-api/testData/referenceResolve/implicitExtensionInvoke.kt");
+    }
+
+    @Test
+    @TestMetadata("implicitFunctionInvoke.kt")
+    public void testImplicitFunctionInvoke() throws Exception {
+        runTest("analysis/analysis-api/testData/referenceResolve/implicitFunctionInvoke.kt");
+    }
+
+    @Test
+    @TestMetadata("implicitFunctionalInterfaceInvoke.kt")
+    public void testImplicitFunctionalInterfaceInvoke() throws Exception {
+        runTest("analysis/analysis-api/testData/referenceResolve/implicitFunctionalInterfaceInvoke.kt");
+    }
+
     @Test
     @TestMetadata("ImportFromRootScope.kt")
     public void testImportFromRootScope() throws Exception {

analysis/analysis-api/testData/referenceResolve/implicitExtensionInvoke.kt

@@ -0,0 +1,5 @@
+fun foo(a: Int) {
+    <caret>a()
+}
+
+operator fun Int.invoke() {}

analysis/analysis-api/testData/referenceResolve/implicitExtensionInvoke.txt

@@ -0,0 +1,2 @@
+Resolved to:
+0: value-parameter a: kotlin.Int

analysis/analysis-api/testData/referenceResolve/implicitFunctionInvoke.kt

@@ -0,0 +1,3 @@
+fun foo(a: () -> Unit) {
+    <caret>a()
+}

analysis/analysis-api/testData/referenceResolve/implicitFunctionInvoke.txt

@@ -0,0 +1,2 @@
+Resolved to:
+0: value-parameter a: () -> kotlin.Unit

analysis/analysis-api/testData/referenceResolve/implicitFunctionalInterfaceInvoke.kt

@@ -0,0 +1,6 @@
+fun interface A {
+    operator fun invoke()
+}
+fun foo(a: A) {
+    <caret>a()
+}

analysis/analysis-api/testData/referenceResolve/implicitFunctionalInterfaceInvoke.txt

@@ -0,0 +1,2 @@
+Resolved to:
+0: value-parameter a: A