FIR: handle double-imported constructors properly

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

@@ -73,15 +73,17 @@ internal fun FirScope.processFunctionsAndConstructorsByName(
     processFunctionsByName(callInfo.name, processor)
 }
 
+private data class SymbolWithSubstitutor(val symbol: FirClassifierSymbol<*>, val substitutor: ConeSubstitutor)
+
 private fun FirScope.getFirstClassifierOrNull(
     callInfo: CallInfo,
     session: FirSession,
     bodyResolveComponents: BodyResolveComponents
-): Pair<FirClassifierSymbol<*>, ConeSubstitutor>? {
+): SymbolWithSubstitutor? {
     var isSuccessResult = false
     var isAmbiguousResult = false
-    var result: Pair<FirClassifierSymbol<*>, ConeSubstitutor>? = null
+    var result: SymbolWithSubstitutor? = null
-    processClassifiersByNameWithSubstitution(callInfo.name) { symbol, substitution ->
+    processClassifiersByNameWithSubstitution(callInfo.name) { symbol, substitutor ->
         val classifierDeclaration = symbol.fir
         var isSuccessCandidate = true
         if (classifierDeclaration is FirMemberDeclaration) {
@@ -103,11 +105,25 @@ private fun FirScope.getFirstClassifierOrNull(
             isSuccessCandidate = false
         }
 
-        if (result == null || (!isSuccessResult && isSuccessCandidate)) {
+        when {
-            isSuccessResult = isSuccessCandidate
+            isSuccessCandidate && !isSuccessResult -> {
-            result = symbol to substitution
+                // any result is better than no result
-        } else {
+                isSuccessResult = true
-            isAmbiguousResult = true
+                result = SymbolWithSubstitutor(symbol, substitutor)
+            }
+            result?.symbol === symbol -> {
+                // miss identical results
+                return@processClassifiersByNameWithSubstitution
+            }
+            result != null -> {
+                // results are similar => ambiguity
+                isAmbiguousResult = true
+            }
+            else -> {
+                // result == null: any result is better than no result
+                isSuccessResult = isSuccessCandidate
+                result = SymbolWithSubstitutor(symbol, substitutor)
+            }
         }
     }
 

compiler/testData/diagnostics/tests/imports/DoubleImports.fir.kt

@@ -1,41 +0,0 @@
-// FILE: StarImported.kt
-
-package star
-
-class SomeClass
-
-fun foo() {}
-
-val bar = 1
-
-// FILE: ExplicitImported.kt
-
-package explicit
-
-class AnotherClass
-
-fun baz() {}
-
-val gau = 2
-
-// FILE: Test.kt
-
-import star.*
-import star.*
-import explicit.<!CONFLICTING_IMPORT!>AnotherClass<!>
-import explicit.<!CONFLICTING_IMPORT!>AnotherClass<!>
-import explicit.baz
-import explicit.baz
-import explicit.gau
-import explicit.gau
-
-fun useSomeClass(): SomeClass = <!RESOLUTION_TO_CLASSIFIER!>SomeClass<!>()
-
-fun useAnotherClass(): AnotherClass = <!RESOLUTION_TO_CLASSIFIER!>AnotherClass<!>()
-
-fun test() {
-    foo()
-    baz()
-    val x = bar
-    val y = gau
-}

compiler/testData/diagnostics/tests/imports/DoubleImports.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // FILE: StarImported.kt
 
 package star