FIR IDE: resolve implicit ctor delegation calls

idea/idea-frontend-fir/src/org/jetbrains/kotlin/idea/frontend/api/fir/components/KtFirCallResolver.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.idea.frontend.api.fir.components
 import org.jetbrains.kotlin.builtins.StandardNames
 import org.jetbrains.kotlin.fir.FirSourceElement
 import org.jetbrains.kotlin.fir.analysis.diagnostics.FirDiagnostic
+import org.jetbrains.kotlin.fir.declarations.FirConstructor
 import org.jetbrains.kotlin.fir.expressions.*
 import org.jetbrains.kotlin.fir.realPsi
 import org.jetbrains.kotlin.fir.references.*
@@ -71,6 +72,7 @@ internal class KtFirCallResolver(
             is FirFunctionCall -> resolveCall(fir)
             is FirAnnotationCall -> fir.asAnnotationCall()
             is FirDelegatedConstructorCall -> fir.asDelegatedConstructorCall()
+            is FirConstructor -> fir.asDelegatedConstructorCall()
             is FirSafeCallExpression -> fir.regularQualifiedAccess.safeAs<FirFunctionCall>()?.let { resolveCall(it) }
             else -> null
         }
@@ -132,6 +134,18 @@ internal class KtFirCallResolver(
         return KtDelegatedConstructorCall(createArgumentMapping(), target, kind)
     }
 
+    private fun FirConstructor.asDelegatedConstructorCall(): KtDelegatedConstructorCall? {
+        // A delegation call may not be present in the source code:
+        //
+        //   class A {
+        //     constructor(i: Int)   // <--- implicit constructor delegation call (empty element after RPAR)
+        //   }
+        //
+        // and FIR built/found from that implicit `KtConstructorDelegationCall` is `FirConstructor`,
+        // which may have a pointer to the delegated constructor.
+        return delegatedConstructor?.asDelegatedConstructorCall()
+    }
+
     private fun FirReference.createCallTarget(): KtCallTarget? {
         return when (this) {
             is FirSuperReference -> createCallTarget(source)

idea/idea-frontend-fir/testData/analysisSession/resolveCall/implicitConstructorDelegationCall.kt

@@ -0,0 +1,9 @@
+class A {
+    constructor(i: Int)
+}
+
+fun call() {
+    val a = <expr>A(42)</expr>
+}
+
+// CALL: KtFunctionCall: targetFunction = <constructor>(i: kotlin.Int): A

idea/idea-frontend-fir/testData/analysisSession/resolveCall/implicitConstructorDelegationCall.txt

@@ -0,0 +1,3 @@
+KtFunctionCall:
+argumentMapping = { 42 -> (i: kotlin.Int) }
+targetFunction = <constructor>(i: kotlin.Int): A

idea/idea-frontend-fir/testData/symbols/symbolByPsi/implicitConstructorDelegationCall.kt

@@ -0,0 +1,3 @@
+class A {
+    constructor(i: Int)
+}

idea/idea-frontend-fir/testData/symbols/symbolByPsi/implicitConstructorDelegationCall.txt

@@ -0,0 +1,52 @@
+KtFirValueParameterSymbol:
+  annotatedType: [] kotlin/Int
+  annotationClassIds: []
+  annotations: []
+  callableIdIfNonLocal: null
+  hasDefaultValue: false
+  isExtension: false
+  isVararg: false
+  name: i
+  origin: SOURCE
+  receiverType: null
+  symbolKind: LOCAL
+
+KtFirConstructorSymbol:
+  annotatedType: [] A
+  annotationClassIds: []
+  annotations: []
+  callableIdIfNonLocal: null
+  containingClassIdIfNonLocal: A
+  dispatchType: null
+  hasStableParameterNames: true
+  isExtension: false
+  isPrimary: false
+  origin: SOURCE
+  receiverType: null
+  symbolKind: MEMBER
+  typeParameters: []
+  valueParameters: [
+    KtFirValueParameterSymbol(i)
+  ]
+  visibility: Public
+
+KtFirNamedClassOrObjectSymbol:
+  annotationClassIds: []
+  annotations: []
+  classIdIfNonLocal: A
+  classKind: CLASS
+  companionObject: null
+  isData: false
+  isExternal: false
+  isFun: false
+  isInline: false
+  isInner: false
+  modality: FINAL
+  name: A
+  origin: SOURCE
+  superTypes: [
+    [] kotlin/Any
+  ]
+  symbolKind: TOP_LEVEL
+  typeParameters: []
+  visibility: Public

idea/idea-frontend-fir/tests/org/jetbrains/kotlin/idea/fir/frontend/api/fir/ResolveCallTestGenerated.java

@@ -66,6 +66,12 @@ public class ResolveCallTestGenerated extends AbstractResolveCallTest {
         runTest("idea/idea-frontend-fir/testData/analysisSession/resolveCall/functionWithReceiverSafeCall.kt");
     }
 
+    @Test
+    @TestMetadata("implicitConstructorDelegationCall.kt")
+    public void testImplicitConstructorDelegationCall() throws Exception {
+        runTest("idea/idea-frontend-fir/testData/analysisSession/resolveCall/implicitConstructorDelegationCall.kt");
+    }
+
     @Test
     @TestMetadata("implicitConstuctorCall.kt")
     public void testImplicitConstuctorCall() throws Exception {

idea/idea-frontend-fir/tests/org/jetbrains/kotlin/idea/fir/frontend/api/symbols/SymbolByPsiTestGenerated.java

@@ -96,6 +96,12 @@ public class SymbolByPsiTestGenerated extends AbstractSymbolByPsiTest {
         runTest("idea/idea-frontend-fir/testData/symbols/symbolByPsi/functionWithTypeParams.kt");
     }
 
+    @Test
+    @TestMetadata("implicitConstructorDelegationCall.kt")
+    public void testImplicitConstructorDelegationCall() throws Exception {
+        runTest("idea/idea-frontend-fir/testData/symbols/symbolByPsi/implicitConstructorDelegationCall.kt");
+    }
+
     @Test
     @TestMetadata("implicitReturn.kt")
     public void testImplicitReturn() throws Exception {