From 1c446151e7da0e7e6ac977e8298795bfe58a87ce Mon Sep 17 00:00:00 2001
From: Kirill Rakhman <kirill.rakhman@jetbrains.com>
Date: Mon, 28 Aug 2023 13:16:54 +0200
Subject: [PATCH] [FIR] Skip resolvable package names in front of
 UNRESOLVED_REFERENCE

#KT-55471
---
 ...onClassWithJavaTarget.out_of_src_roots.txt | 18 +++++-----
 .../lazyResolve/annotationParameters.txt      | 18 +++++-----
 .../annotationParametersScript.txt            | 22 ++++++-------
 .../FirSpecificTypeResolverTransformer.kt     | 33 ++++++++++++++++++-
 .../nativeTests/cloneableInNative.fir.kt      |  2 +-
 .../diagnostics/tests/ResolveToJava.fir.kt    |  4 +--
 .../unresolvedReferenceRange.fir.kt           |  5 ---
 .../annotations/unresolvedReferenceRange.kt   |  1 +
 .../fieldAsClassDelegate.fir.kt               |  2 +-
 .../suspendFunctionN.fir.kt                   |  4 ---
 .../suspendFunctionType/suspendFunctionN.kt   |  1 +
 .../jdkModulesFromNamed/main.fir.txt          |  4 +--
 .../releaseFlag/moduleSwing.fir.txt           |  4 +--
 13 files changed, 71 insertions(+), 47 deletions(-)
 delete mode 100644 compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.fir.kt
 delete mode 100644 compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.fir.kt

diff --git a/analysis/low-level-api-fir/testdata/lazyResolve/annotationClassWithJavaTarget.out_of_src_roots.txt b/analysis/low-level-api-fir/testdata/lazyResolve/annotationClassWithJavaTarget.out_of_src_roots.txt
index 039650e8434..882e88e9690 100644
--- a/analysis/low-level-api-fir/testdata/lazyResolve/annotationClassWithJavaTarget.out_of_src_roots.txt
+++ b/analysis/low-level-api-fir/testdata/lazyResolve/annotationClassWithJavaTarget.out_of_src_roots.txt
@@ -45,7 +45,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 TYPES:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types](ElementType#.TYPE_USE#) public? final? [ResolvedTo(TYPES)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types](ElementType#.TYPE_USE#) public? final? [ResolvedTo(TYPES)] annotation class ResolveMe : R|kotlin/Annotation| {
         public? [ResolvedTo(RAW_FIR)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             LAZY_super<R|kotlin/Any|>
         }
@@ -54,7 +54,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 STATUS:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(STATUS)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(STATUS)] annotation class ResolveMe : R|kotlin/Annotation| {
         public? [ResolvedTo(RAW_FIR)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             LAZY_super<R|kotlin/Any|>
         }
@@ -63,7 +63,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 EXPECT_ACTUAL_MATCHING:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(EXPECT_ACTUAL_MATCHING)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(EXPECT_ACTUAL_MATCHING)] annotation class ResolveMe : R|kotlin/Annotation| {
         public? [ResolvedTo(RAW_FIR)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             LAZY_super<R|kotlin/Any|>
         }
@@ -72,7 +72,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 ARGUMENTS_OF_ANNOTATIONS:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(ARGUMENTS_OF_ANNOTATIONS)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(ARGUMENTS_OF_ANNOTATIONS)] annotation class ResolveMe : R|kotlin/Annotation| {
         public? [ResolvedTo(RAW_FIR)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             LAZY_super<R|kotlin/Any|>
         }
@@ -81,7 +81,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 CONTRACTS:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(CONTRACTS)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(CONTRACTS)] annotation class ResolveMe : R|kotlin/Annotation| {
         public? [ResolvedTo(RAW_FIR)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             LAZY_super<R|kotlin/Any|>
         }
@@ -90,7 +90,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 IMPLICIT_TYPES_BODY_RESOLVE:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(IMPLICIT_TYPES_BODY_RESOLVE)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types](ElementType#.TYPE_USE#) public final [ResolvedTo(IMPLICIT_TYPES_BODY_RESOLVE)] annotation class ResolveMe : R|kotlin/Annotation| {
         public? [ResolvedTo(RAW_FIR)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             LAZY_super<R|kotlin/Any|>
         }
@@ -99,7 +99,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 ANNOTATIONS_ARGUMENTS_MAPPING:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types]() public final [ResolvedTo(ANNOTATIONS_ARGUMENTS_MAPPING)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types]() public final [ResolvedTo(ANNOTATIONS_ARGUMENTS_MAPPING)] annotation class ResolveMe : R|kotlin/Annotation| {
         public? [ResolvedTo(RAW_FIR)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             LAZY_super<R|kotlin/Any|>
         }
@@ -108,7 +108,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 BODY_RESOLVE:
 FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types]() public final [ResolvedTo(BODY_RESOLVE)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types]() public final [ResolvedTo(BODY_RESOLVE)] annotation class ResolveMe : R|kotlin/Annotation| {
         public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             super<R|kotlin/Any|>()
         }
@@ -117,7 +117,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationClassWithJavaTarget.kt
 
 FILE RAW TO BODY:
 FILE: [ResolvedTo(BODY_RESOLVE)] annotationClassWithJavaTarget.kt
-    @<ERROR TYPE REF: Symbol not found for java.lang.annotation.Target>[Types]() public final [ResolvedTo(BODY_RESOLVE)] annotation class ResolveMe : R|kotlin/Annotation| {
+    @<ERROR TYPE REF: Symbol not found for java>[Types]() public final [ResolvedTo(BODY_RESOLVE)] annotation class ResolveMe : R|kotlin/Annotation| {
         public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=ResolveMe] constructor(): R|ResolveMe| {
             super<R|kotlin/Any|>()
         }
diff --git a/analysis/low-level-api-fir/testdata/lazyResolve/annotationParameters.txt b/analysis/low-level-api-fir/testdata/lazyResolve/annotationParameters.txt
index 1a91e22457a..0fa8fef07ed 100644
--- a/analysis/low-level-api-fir/testdata/lazyResolve/annotationParameters.txt
+++ b/analysis/low-level-api-fir/testdata/lazyResolve/annotationParameters.txt
@@ -437,12 +437,12 @@ FILE: [ResolvedTo(IMPORTS)] annotationParameters.kt
 
     }
     public final [ResolvedTo(STATUS)] annotation class Anno : R|kotlin/Annotation| {
-        public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A.X>): R|Anno| {
+        public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A>): R|Anno| {
             LAZY_super<R|kotlin/Any|>
         }
 
-        public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A.X> = R|<local>/args|
-            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A.X>
+        public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A> = R|<local>/args|
+            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A>
 
     }
     public final [ResolvedTo(STATUS)] class B : R|kotlin/Any| {
@@ -476,12 +476,12 @@ FILE: [ResolvedTo(IMPORTS)] annotationParameters.kt
 
     }
     public final [ResolvedTo(STATUS)] annotation class Anno : R|kotlin/Annotation| {
-        public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A.X>): R|Anno| {
+        public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A>): R|Anno| {
             LAZY_super<R|kotlin/Any|>
         }
 
-        public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A.X> = R|<local>/args|
-            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A.X>
+        public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A> = R|<local>/args|
+            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A>
 
     }
     public final [ResolvedTo(STATUS)] class B : R|kotlin/Any| {
@@ -515,12 +515,12 @@ FILE: [ResolvedTo(BODY_RESOLVE)] annotationParameters.kt
 
     }
     public final [ResolvedTo(BODY_RESOLVE)] annotation class Anno : R|kotlin/Annotation| {
-        public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] constructor([ResolvedTo(BODY_RESOLVE)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A.X>): R|Anno| {
+        public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] constructor([ResolvedTo(BODY_RESOLVE)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A>): R|Anno| {
             super<R|kotlin/Any|>()
         }
 
-        public final [ResolvedTo(BODY_RESOLVE)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A.X> = R|<local>/args|
-            public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A.X>
+        public final [ResolvedTo(BODY_RESOLVE)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A> = R|<local>/args|
+            public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A>
 
     }
     public final [ResolvedTo(BODY_RESOLVE)] class B : R|kotlin/Any| {
diff --git a/analysis/low-level-api-fir/testdata/lazyResolve/annotationParametersScript.txt b/analysis/low-level-api-fir/testdata/lazyResolve/annotationParametersScript.txt
index df7897e76b9..26830ea60ee 100644
--- a/analysis/low-level-api-fir/testdata/lazyResolve/annotationParametersScript.txt
+++ b/analysis/low-level-api-fir/testdata/lazyResolve/annotationParametersScript.txt
@@ -519,12 +519,12 @@ FILE: [ResolvedTo(IMPORTS)] annotationParametersScript.kts
         }
 
         public final [ResolvedTo(STATUS)] annotation class Anno : R|kotlin/Annotation| {
-            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A.X>): R|Anno| {
+            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A>): R|Anno| {
                 LAZY_super<R|kotlin/Any|>
             }
 
-            public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A.X> = R|<local>/args|
-                public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A.X>
+            public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A> = R|<local>/args|
+                public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A>
 
         }
 
@@ -544,7 +544,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationParametersScript.kts
 BODY_RESOLVE:
 FILE: [ResolvedTo(IMPORTS)] annotationParametersScript.kts
     context(<script>@R|kotlin/script/templates/standard/ScriptTemplateWithArgs|)
-    SCRIPT: [ResolvedTo(TYPES)] 
+    SCRIPT: [ResolvedTo(TYPES)]
         [ResolvedTo(RAW_FIR)] lval args: R|kotlin/Array<kotlin/String>|
 
         public final [ResolvedTo(STATUS)] enum class X : R|kotlin/Enum<X>| {
@@ -565,12 +565,12 @@ FILE: [ResolvedTo(IMPORTS)] annotationParametersScript.kts
         }
 
         public final [ResolvedTo(STATUS)] annotation class Anno : R|kotlin/Annotation| {
-            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A.X>): R|Anno| {
+            public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] constructor([ResolvedTo(STATUS)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A>): R|Anno| {
                 LAZY_super<R|kotlin/Any|>
             }
 
-            public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A.X> = R|<local>/args|
-                public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A.X>
+            public final [ResolvedTo(STATUS)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A> = R|<local>/args|
+                public [ResolvedTo(STATUS)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A>
 
         }
 
@@ -590,7 +590,7 @@ FILE: [ResolvedTo(IMPORTS)] annotationParametersScript.kts
 FILE RAW TO BODY:
 FILE: [ResolvedTo(BODY_RESOLVE)] annotationParametersScript.kts
     context(<script>@R|kotlin/script/templates/standard/ScriptTemplateWithArgs|)
-    SCRIPT: [ResolvedTo(BODY_RESOLVE)] 
+    SCRIPT: [ResolvedTo(BODY_RESOLVE)]
         [ResolvedTo(BODY_RESOLVE)] lval args: R|kotlin/Array<kotlin/String>|
 
         public final [ResolvedTo(BODY_RESOLVE)] enum class X : R|kotlin/Enum<X>| {
@@ -611,12 +611,12 @@ FILE: [ResolvedTo(BODY_RESOLVE)] annotationParametersScript.kts
         }
 
         public final [ResolvedTo(BODY_RESOLVE)] annotation class Anno : R|kotlin/Annotation| {
-            public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] constructor([ResolvedTo(BODY_RESOLVE)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A.X>): R|Anno| {
+            public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] constructor([ResolvedTo(BODY_RESOLVE)] [CorrespondingProperty=/Anno.args] args: <ERROR TYPE REF: Symbol not found for A>): R|Anno| {
                 super<R|kotlin/Any|>()
             }
 
-            public final [ResolvedTo(BODY_RESOLVE)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A.X> = R|<local>/args|
-                public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A.X>
+            public final [ResolvedTo(BODY_RESOLVE)] [IsFromPrimaryConstructor=true] val args: <ERROR TYPE REF: Symbol not found for A> = R|<local>/args|
+                public [ResolvedTo(BODY_RESOLVE)] [ContainingClassKey=Anno] get(): <ERROR TYPE REF: Symbol not found for A>
 
         }
 
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirSpecificTypeResolverTransformer.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirSpecificTypeResolverTransformer.kt
index 635b263506b..811ccd16903 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirSpecificTypeResolverTransformer.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirSpecificTypeResolverTransformer.kt
@@ -22,12 +22,14 @@ import org.jetbrains.kotlin.fir.resolve.FirTypeResolutionResult
 import org.jetbrains.kotlin.fir.resolve.SupertypeSupplier
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnresolvedTypeQualifierError
 import org.jetbrains.kotlin.fir.resolve.diagnostics.ConeUnsupportedDefaultValueInFunctionType
+import org.jetbrains.kotlin.fir.resolve.providers.symbolProvider
 import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.resultType
 import org.jetbrains.kotlin.fir.resolve.typeResolver
 import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.buildErrorTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.fir.types.builder.buildUserTypeRef
+import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.util.PrivateForInline
 
 class FirSpecificTypeResolverTransformer(
@@ -195,7 +197,9 @@ class FirSpecificTypeResolverTransformer(
 
             if (diagnostic is ConeUnresolvedTypeQualifierError) {
                 val totalQualifierCount = diagnostic.qualifiers.size
-                val resolvedQualifierCount = (partiallyResolvedTypeRef?.delegatedTypeRef as? FirUserTypeRef)?.qualifier?.size ?: 0
+                val resolvedQualifierCount = (partiallyResolvedTypeRef?.delegatedTypeRef as? FirUserTypeRef)?.qualifier?.size
+                    ?: calculatePartiallyResolvablePackageSegments(diagnostic.qualifiers)
+
                 val unresolvedQualifierCount = totalQualifierCount - resolvedQualifierCount
 
                 if (unresolvedQualifierCount > 1) {
@@ -207,6 +211,7 @@ class FirSpecificTypeResolverTransformer(
         }
     }
 
+
     /**
      * Tries to calculate a partially resolved type reference for a type reference which was resolved to an error type.
      * It will attempt to resolve the type with a decreasing number of qualifiers until it succeeds, allowing
@@ -242,6 +247,32 @@ class FirSpecificTypeResolverTransformer(
         return null
     }
 
+
+    /**
+     * If the given [qualifiers] are interpreted as a fully qualified name,
+     * calculates how many segments (from the left) can be resolved to an existing package.
+     *
+     * This is useful for providing better IDE support when resolving partially incorrect types.
+     *
+     * The last segment is never considered, i.e., if [qualifiers] is not empty, the result is always `< qualifiers.size`.
+     */
+    private fun calculatePartiallyResolvablePackageSegments(qualifiers: List<FirQualifierPart>): Int {
+        if (qualifiers.size <= 1) {
+            return 0
+        }
+
+        val packageSegmentsToTry = qualifiers.mapTo(mutableListOf()) { it.name.asString() }
+
+        while (packageSegmentsToTry.size > 1) {
+            packageSegmentsToTry.removeLast()
+            if (session.symbolProvider.getPackage(FqName.fromSegments(packageSegmentsToTry)) != null) {
+                return packageSegmentsToTry.size
+            }
+        }
+
+        return 0
+    }
+
     private fun ConeKotlinType.takeIfAcceptable(): ConeKotlinType? = this.takeUnless {
         !errorTypeAsResolved && it is ConeErrorType
     }
diff --git a/compiler/testData/diagnostics/nativeTests/cloneableInNative.fir.kt b/compiler/testData/diagnostics/nativeTests/cloneableInNative.fir.kt
index 09560b710eb..3d6e17f0bb2 100644
--- a/compiler/testData/diagnostics/nativeTests/cloneableInNative.fir.kt
+++ b/compiler/testData/diagnostics/nativeTests/cloneableInNative.fir.kt
@@ -1,6 +1,6 @@
 // ISSUE: KT-58549
 
 fun main() {
-    val x: <!UNRESOLVED_REFERENCE!>kotlin.Cloneable<!> = if (true) intArrayOf(1) else longArrayOf(1)
+    val x: kotlin.<!UNRESOLVED_REFERENCE!>Cloneable<!> = if (true) intArrayOf(1) else longArrayOf(1)
     x
 }
diff --git a/compiler/testData/diagnostics/tests/ResolveToJava.fir.kt b/compiler/testData/diagnostics/tests/ResolveToJava.fir.kt
index 90190beda55..046b2a22ef7 100644
--- a/compiler/testData/diagnostics/tests/ResolveToJava.fir.kt
+++ b/compiler/testData/diagnostics/tests/ResolveToJava.fir.kt
@@ -15,10 +15,10 @@ import <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.lang.Comparable<!> as Com
 val l : MutableList<in Int> = ArrayList<Int>()
 
 fun test(l : <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.util.List<Int><!>) {
-  val <!UNUSED_VARIABLE!>x<!> : <!UNRESOLVED_REFERENCE!>java<!>.List
+  val <!UNUSED_VARIABLE!>x<!> : java.<!UNRESOLVED_REFERENCE!>List<!>
   val <!UNUSED_VARIABLE!>y<!> : <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.util.List<Int><!>
   val <!UNUSED_VARIABLE!>b<!> : <!PLATFORM_CLASS_MAPPED_TO_KOTLIN!>java.lang.Object<!>
-  val <!UNUSED_VARIABLE!>z<!> : <!UNRESOLVED_REFERENCE!>java<!>.utils.List<Int>
+  val <!UNUSED_VARIABLE!>z<!> : java.<!UNRESOLVED_REFERENCE!>utils<!>.List<Int>
 
   val <!UNUSED_VARIABLE!>f<!> : java.io.File? = null
 
diff --git a/compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.fir.kt b/compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.fir.kt
deleted file mode 100644
index 3cf30b4ea9b..00000000000
--- a/compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.fir.kt
+++ /dev/null
@@ -1,5 +0,0 @@
-@<!UNRESOLVED_REFERENCE!>Ann<!> class A
-@<!UNRESOLVED_REFERENCE!>Ann<!> class B
-@<!UNRESOLVED_REFERENCE!>Ann<!>(1) class C
-@<!UNRESOLVED_REFERENCE!>kotlin<!>.Ann(1) class D
-@<!UNRESOLVED_REFERENCE!>kotlin<!>.annotation.Ann(1) class E
diff --git a/compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.kt b/compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.kt
index c478ee26d62..3f80fa75d43 100644
--- a/compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.kt
+++ b/compiler/testData/diagnostics/tests/annotations/unresolvedReferenceRange.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 @<!UNRESOLVED_REFERENCE!>Ann<!> class A
 @<!UNRESOLVED_REFERENCE!>Ann<!> class B
 @<!UNRESOLVED_REFERENCE!>Ann<!>(1) class C
diff --git a/compiler/testData/diagnostics/tests/controlFlowAnalysis/fieldAsClassDelegate.fir.kt b/compiler/testData/diagnostics/tests/controlFlowAnalysis/fieldAsClassDelegate.fir.kt
index cf43d817d00..c5ebffdee11 100644
--- a/compiler/testData/diagnostics/tests/controlFlowAnalysis/fieldAsClassDelegate.fir.kt
+++ b/compiler/testData/diagnostics/tests/controlFlowAnalysis/fieldAsClassDelegate.fir.kt
@@ -22,7 +22,7 @@ object DefaultHttpClientWithFun : HttpClient by fClient() {
 
 private fun fClient() = HttpClientImpl()
 
-private fun <T> lazy(init: () -> T): <!UNRESOLVED_REFERENCE!>kotlin<!>.Lazy<T> {
+private fun <T> lazy(init: () -> T): kotlin.<!UNRESOLVED_REFERENCE!>Lazy<!><T> {
     init()
     null!!
 }
diff --git a/compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.fir.kt
deleted file mode 100644
index 9259e28a103..00000000000
--- a/compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.fir.kt
+++ /dev/null
@@ -1,4 +0,0 @@
-// SKIP_JAVAC
-typealias Test1 = <!UNRESOLVED_REFERENCE!>SuspendFunction0<!><Unit>
-typealias Test2 = <!UNRESOLVED_REFERENCE!>kotlin<!>.SuspendFunction0<Unit>
-typealias Test3 = kotlin.coroutines.SuspendFunction0<Unit>
diff --git a/compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.kt b/compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.kt
index 59bd0c5fce7..76d1ddea64b 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/coroutines/suspendFunctionType/suspendFunctionN.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // SKIP_JAVAC
 typealias Test1 = <!UNRESOLVED_REFERENCE!>SuspendFunction0<!><Unit>
 typealias Test2 = kotlin.<!UNRESOLVED_REFERENCE!>SuspendFunction0<!><Unit>
diff --git a/compiler/testData/javaModules/jdkModulesFromNamed/main.fir.txt b/compiler/testData/javaModules/jdkModulesFromNamed/main.fir.txt
index e7301ec5401..083a8d4cf2e 100644
--- a/compiler/testData/javaModules/jdkModulesFromNamed/main.fir.txt
+++ b/compiler/testData/javaModules/jdkModulesFromNamed/main.fir.txt
@@ -1,6 +1,6 @@
-compiler/testData/javaModules/jdkModulesFromNamed/main/test.kt:11:12: error: unresolved reference 'javax.swing.JFrame'.
+compiler/testData/javaModules/jdkModulesFromNamed/main/test.kt:11:18: error: unresolved reference 'swing'.
     val s: javax.swing.JFrame? = null
-           ^
+                 ^
 compiler/testData/javaModules/jdkModulesFromNamed/main/test.kt:12:5: error: overload resolution ambiguity between candidates: [@InlineOnly() fun println(message: Any?): Unit, @InlineOnly() fun println(message: Boolean): Unit, @InlineOnly() fun println(message: Byte): Unit, ...]
     println(s)
     ^
diff --git a/compiler/testData/javaModules/releaseFlag/moduleSwing.fir.txt b/compiler/testData/javaModules/releaseFlag/moduleSwing.fir.txt
index c0a66ae96e0..b554d93da2f 100644
--- a/compiler/testData/javaModules/releaseFlag/moduleSwing.fir.txt
+++ b/compiler/testData/javaModules/releaseFlag/moduleSwing.fir.txt
@@ -1,4 +1,4 @@
-compiler/testData/javaModules/releaseFlag/moduleSwing/foo/Foo.kt:5:12: error: unresolved reference 'javax.swing.JFrame'.
+compiler/testData/javaModules/releaseFlag/moduleSwing/foo/Foo.kt:5:18: error: unresolved reference 'swing'.
     val z: javax.swing.JFrame? = null
-           ^
+                 ^
 COMPILATION_ERROR