new inference: don't treat void as primitive type to boxing

java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/constraints/TypeCompatibilityConstraint.java

@@ -45,14 +45,14 @@ public class TypeCompatibilityConstraint implements ConstraintFormula {
       }
       return assignable;
     }
-    if (myS instanceof PsiPrimitiveType) {
+    if (myS instanceof PsiPrimitiveType && !PsiType.VOID.equals(myS)) {
       final PsiClassType boxedType = ((PsiPrimitiveType)myS).getBoxedType(session.getManager(), session.getScope());
       if (boxedType != null) {
         constraints.add(new TypeCompatibilityConstraint(myT, boxedType));
         return true;
       }
     }
-    if (myT instanceof PsiPrimitiveType) {
+    if (myT instanceof PsiPrimitiveType && !PsiType.VOID.equals(myT)) {
       final PsiClassType boxedType = ((PsiPrimitiveType)myT).getBoxedType(session.getManager(), session.getScope());
       if (boxedType != null) {
         constraints.add(new TypeEqualityConstraint(boxedType, myS));

java/java-tests/testData/codeInsight/daemonCodeAnalyzer/lambda/overloadResolution/FunctionalInterfaceIncompatibilityBasedOnAbsenceOfVoidToTypeConvertion.java

@@ -0,0 +1,14 @@
+import java.util.function.Supplier;
+
+class ABC {
+  private <T> void <warning descr="Private method 'foo(java.util.function.Supplier<T>)' is never used">foo</warning>(Supplier<T> <warning descr="Parameter 'dictSeqs' is never used">dictSeqs</warning>) {
+  }
+  private void foo(Runnable <warning descr="Parameter 'r' is never used">r</warning>) {}
+
+  {
+    foo(() -> bar());
+    foo(this::bar);
+  }
+
+  void bar(){}
+}

java/java-tests/testSrc/com/intellij/codeInsight/daemon/lambda/OverloadResolutionTest.java

@@ -171,6 +171,10 @@ public class OverloadResolutionTest extends LightDaemonAnalyzerTestCase {
     doTest();
   }
 
+  public void testFunctionalInterfaceIncompatibilityBasedOnAbsenceOfVoidToTypeConvertion() throws Exception {
+    doTest();
+  }
+
   private void doTest() {
     doTest(true);
   }