From e59155ed165b491c72b50cce7094eeb6d9e8086f Mon Sep 17 00:00:00 2001
From: Anna Kozlova <anna.kozlova@jetbrains.com>
Date: Thu, 29 Apr 2021 21:04:47 +0200
Subject: [PATCH] java: discard functional expressions with unbounded wildcards
 which type parameters depend on other type parameters (IDEA-267644)

old spec issue is still not resolved and most probably won't be resolved in the future as would lead to the incompatibilities

GitOrigin-RevId: be74d8ca83ce3c47d1e3dc9eb08de789fb881d2b
---
 ...nctionalInterfaceParameterizationUtil.java |  3 +++
 .../NonWildcardParametrization.java           | 21 +++++++++++++------
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/FunctionalInterfaceParameterizationUtil.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/FunctionalInterfaceParameterizationUtil.java
index cf447b2262a1..0036dfce30a8 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/FunctionalInterfaceParameterizationUtil.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/FunctionalInterfaceParameterizationUtil.java
@@ -175,6 +175,9 @@ public final class FunctionalInterfaceParameterizationUtil {
           final PsiType bound = ((PsiWildcardType)paramType).getBound();
           for (PsiClassType paramBound : typeParameters[i].getExtendsListTypes()) {
             if (PsiTypesUtil.mentionsTypeParameters(paramBound, typeParametersSet)) {
+              if (bound == null) {
+                return null;
+              }
               newParameters[i] = bound;
               continue next;
             }
diff --git a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/wildcardParametrization/NonWildcardParametrization.java b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/wildcardParametrization/NonWildcardParametrization.java
index e1c14d30abee..c499111a2546 100644
--- a/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/wildcardParametrization/NonWildcardParametrization.java
+++ b/java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/wildcardParametrization/NonWildcardParametrization.java
@@ -36,9 +36,9 @@ class ExtendsList {
   }
 
   {
-    I<?, ? extends String> n = () -> null;
-    I<?, ?> n1 = () -> null;
-    I<?, String> n2 = () -> null;
+    I<?, ? extends String> n = <error descr="Cannot infer functional interface type">() -> null</error>;
+    I<?, ?> n1 = <error descr="Cannot infer functional interface type">() -> null</error>;
+    I<?, String> n2 = <error descr="Cannot infer functional interface type">() -> null</error>;
 
 
     I<? extends List<?>, String> e1 = <error descr="Cannot infer functional interface type">() -> null</error>;
@@ -59,7 +59,7 @@ class MultipleBounds {
   interface LC<K> extends List<K>, Comparable<K> {}
 
   {
-    I<?, String> n = () -> null;
+    I<?, String> n = <error descr="Cannot infer functional interface type">() -> null</error>;
 
     I<? extends List<String>, ? extends String> e1 = <error descr="Cannot infer functional interface type">() -> null</error>;
     I<? extends Comparable<String>, ? extends String> e2 = <error descr="Cannot infer functional interface type">() -> null</error>;
@@ -77,7 +77,7 @@ class FirstIndependentBound {
   interface LC<K> extends List<String>, Comparable<K> {}
 
   {
-    I<?, String> n = () -> null;
+    I<?, String> n = <error descr="Cannot infer functional interface type">() -> null</error>;
 
     I<? extends List<String>, ? extends String> e1 = <error descr="Cannot infer functional interface type">() -> null</error>;
     I<? extends Comparable<String>, ? extends String> e2 = <error descr="Cannot infer functional interface type">() -> null</error>;
@@ -96,7 +96,7 @@ class SecondIndependentBound {
   interface LC<K> extends List<String>, Comparable<K> {}
 
   {
-    I<?, String> n = () -> null;
+    I<?, String> n = <error descr="Cannot infer functional interface type">() -> null</error>;
 
     I<? extends List<String>, ? extends String> e1 = <error descr="Cannot infer functional interface type">() -> null</error>;
     I<? extends Comparable<String>, ? extends String> e2 = <error descr="Cannot infer functional interface type">() -> null</error>;
@@ -105,4 +105,13 @@ class SecondIndependentBound {
     I<? extends LC<? extends String>, String> e5 = <error descr="Cannot infer functional interface type">()  -> null</error>;
     I<? extends LC<? extends String>, ? extends String> e6 = <error descr="Cannot infer functional interface type">()  -> null</error>;
   }
+}
+
+interface Unbound<A extends Number, B extends A> {
+  void accept();
+
+  static void m() {
+    Unbound<?, ?> s = <error descr="Cannot infer functional interface type">() -> {}</error>;
+    Unbound<?, ? extends Number> s1 = () -> {};
+  }
 }
\ No newline at end of file