Add "unused equals" warning on direct equals call #KT-21192 Fixed

idea/testData/inspections/unusedEquals/consumer/ConsumerVoid.java

@@ -0,0 +1,5 @@
+package consumer;
+
+public interface ConsumerVoid<T> {
+    void consumer(T t);
+}

idea/testData/inspections/unusedEquals/inspectionData/expected.xml

@@ -79,4 +79,22 @@
         <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused equals expression</problem_class>
         <description>Unused equals expression</description>
     </problem>
+
+    <problem>
+        <file>test.kt</file>
+        <line>71</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused equals expression</problem_class>
+        <description>Unused equals expression</description>
+    </problem>
+
+    <problem>
+        <file>test.kt</file>
+        <line>75</line>
+        <module>light_idea_test_case</module>
+        <entry_point TYPE="file" FQNAME="temp:///src/test.kt" />
+        <problem_class severity="WARNING" attribute_key="NOT_USED_ELEMENT_ATTRIBUTES">Unused equals expression</problem_class>
+        <description>Unused equals expression</description>
+    </problem>
 </problems>

idea/testData/inspections/unusedEquals/test.kt

@@ -67,6 +67,14 @@ fun foo9() {
     consumer.Consumer<Any?> { it == null } // used
 }
 
+fun foo9a() {
+    consumer.ConsumerVoid<Any?> { it == null } // not used
+}
+
+fun foo9b() {
+    consumer.ConsumerVoid<Any?> { it.equals(null) } // not used
+}
+
 class Test(val successCondition: (Int) -> Boolean) {
     fun pass(num: Int): Boolean = successCondition(num)
 }