From 9f6a81278657908362706495b58802e81e780b02 Mon Sep 17 00:00:00 2001
From: Simon Ogorodnik <simon.ogorodnik@jetbrains.com>
Date: Fri, 19 Nov 2021 04:19:18 +0300
Subject: [PATCH] Fix multiple registration of same type variable in builder
 inference

---
 .../inference/BuilderInferenceSession.kt      |  8 +++----
 .../stubTypes/commonSuperTypeContravariant.kt | 24 +++++++++----------
 2 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/BuilderInferenceSession.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/BuilderInferenceSession.kt
index f10a37c0364..72f7d473908 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/BuilderInferenceSession.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/inference/BuilderInferenceSession.kt
@@ -325,14 +325,12 @@ class BuilderInferenceSession(
         shouldIntegrateAllConstraints: Boolean
     ) {
         storage.notFixedTypeVariables.values.forEach {
-            if (it.typeVariable.freshTypeConstructor(commonSystem.typeSystemContext) !in commonSystem.allTypeVariables) {
-                commonSystem.registerVariable(it.typeVariable)
-            }
+            commonSystem.registerTypeVariableIfNotPresent(it.typeVariable)
         }
 
         for (parentSession in findAllParentBuildInferenceSessions()) {
             for ((variable, stubType) in parentSession.stubsForPostponedVariables) {
-                commonSystem.registerVariable(variable)
+                commonSystem.registerTypeVariableIfNotPresent(variable)
                 commonSystem.addSubtypeConstraint(
                     variable.defaultType,
                     stubType,
@@ -378,7 +376,7 @@ class BuilderInferenceSession(
         if (shouldIntegrateAllConstraints) {
             for ((variableConstructor, type) in storage.fixedTypeVariables) {
                 val typeVariable = storage.allTypeVariables.getValue(variableConstructor)
-                commonSystem.registerVariable(typeVariable)
+                commonSystem.registerTypeVariableIfNotPresent(typeVariable)
                 commonSystem.addEqualityConstraint((typeVariable as NewTypeVariable).defaultType, type, BuilderInferencePosition)
             }
         }
diff --git a/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.kt b/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.kt
index bccf7a00a0c..312c306726c 100644
--- a/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.kt
+++ b/compiler/testData/diagnostics/tests/inference/builderInference/stubTypes/commonSuperTypeContravariant.kt
@@ -47,24 +47,24 @@ fun test() {
 
         build2 {
             emit(1)
-            select1(this@build.get(), <!TYPE_MISMATCH("In<String>; In<Int?>")!>getIn()<!>)
-            select1(get(), <!TYPE_MISMATCH("In<Int?>; In<String>!")!>Test.foo(this@build.getIn())<!>)
-            select1(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String!>; In<Int?>!")!>Test.foo(getIn())<!>)
-            select1(Test.foo(get()), <!TYPE_MISMATCH("In<Int?>; In<String>")!>this@build.getIn()<!>)
-            select2(this@build.get(), <!TYPE_MISMATCH("In<String?>; In<Int?>")!>getIn()<!>)
+            select1(this@build.get(), <!TYPE_MISMATCH("In<String>; In<Int!>")!>getIn()<!>)
+            select1(get(), <!TYPE_MISMATCH("In<Int!>; In<String>!")!>Test.foo(this@build.getIn())<!>)
+            select1(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String!>; In<Int!>!")!>Test.foo(getIn())<!>)
+            select1(Test.foo(get()), <!TYPE_MISMATCH("In<Int!>; In<String>")!>this@build.getIn()<!>)
+            select2(this@build.get(), <!TYPE_MISMATCH("In<String?>; In<Int!>")!>getIn()<!>)
             select2(get(), <!TYPE_MISMATCH("In<Int?>; In<String>!")!>Test.foo(this@build.getIn())<!>)
-            select2(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String?>; In<Int?>!")!>Test.foo(getIn())<!>)
+            select2(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String?>; In<Int!>!")!>Test.foo(getIn())<!>)
             select2(Test.foo(get()), <!TYPE_MISMATCH("In<Int?>; In<String>")!>this@build.getIn()<!>)
-            select3(this@build.get(), <!TYPE_MISMATCH("In<String?>; In<Int?>")!>getIn()<!>)
+            select3(this@build.get(), <!TYPE_MISMATCH("In<String?>; In<Int!>")!>getIn()<!>)
             select3(get(), <!TYPE_MISMATCH("In<Int?>; In<String>!")!>Test.foo(this@build.getIn())<!>)
-            select3(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String?>; In<Int?>!")!>Test.foo(getIn())<!>)
+            select3(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String?>; In<Int!>!")!>Test.foo(getIn())<!>)
             select3(Test.foo(get()), <!TYPE_MISMATCH("In<Int?>; In<String>")!>this@build.getIn()<!>)
-            select4(this@build.get(), <!TYPE_MISMATCH("In<String>; In<Int?>")!>getIn()<!>)
+            select4(this@build.get(), <!TYPE_MISMATCH("In<String>; In<Int!>")!>getIn()<!>)
             select4(get(), <!TYPE_MISMATCH("In<Int>; In<String>!")!>Test.foo(this@build.getIn())<!>)
-            select4(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String>; In<Int?>!")!>Test.foo(getIn())<!>)
-            select4(Test.foo(get()), <!TYPE_MISMATCH("In<Int?>; In<String>")!>this@build.getIn()<!>)
+            select4(Test.foo(this@build.get()), <!TYPE_MISMATCH("In<String>; In<Int!>!")!>Test.foo(getIn())<!>)
+            select4(Test.foo(get()), <!TYPE_MISMATCH("In<Int!>; In<String>")!>this@build.getIn()<!>)
 
-            select4(id(Test.foo(this@build.get())), <!TYPE_MISMATCH("In<String>; In<Int?>")!>getIn()<!>)
+            select4(id(Test.foo(this@build.get())), <!TYPE_MISMATCH("In<String>; In<Int!>")!>getIn()<!>)
             ""
         }
         ""