Fix NPE on equals/hashCode of local function references

Anonymous classes for local function references implement their
getOwner() as "return null" currently (KT-14291). To avoid NPE in this
case, we now consider two local functions the same if their name and
signature are equal. This is incorrect in general, but unlikely to cause
major problems and is going to be fixed by KT-14291 eventually anyway

 #KT-17055

compiler/testData/codegen/box/callableReference/function/local/equalsHashCode.kt

@@ -0,0 +1,13 @@
+// IGNORE_BACKEND: JS, NATIVE
+
+fun box(): String {
+    fun bar() {}
+    fun baz() {}
+
+    if (!::bar.equals(::bar)) return "Fail 1"
+    if (::bar.hashCode() != ::bar.hashCode()) return "Fail 2"
+
+    if (::bar == ::baz) return "Fail 3"
+
+    return "OK"
+}

compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -2040,6 +2040,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                     doTest(fileName);
                 }
 
+                @TestMetadata("equalsHashCode.kt")
+                public void testEqualsHashCode() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/equalsHashCode.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("extension.kt")
                 public void testExtension() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/extension.kt");

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -2040,6 +2040,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("equalsHashCode.kt")
+                public void testEqualsHashCode() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/equalsHashCode.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("extension.kt")
                 public void testExtension() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/extension.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -2040,6 +2040,12 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                     doTest(fileName);
                 }
 
+                @TestMetadata("equalsHashCode.kt")
+                public void testEqualsHashCode() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/equalsHashCode.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("extension.kt")
                 public void testExtension() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/extension.kt");

core/runtime.jvm/src/kotlin/jvm/internal/FunctionReference.java

@@ -86,7 +86,7 @@ public class FunctionReference extends CallableReference implements FunctionBase
         if (obj instanceof FunctionReference) {
             FunctionReference other = (FunctionReference) obj;
 
-            return getOwner().equals(other.getOwner()) &&
+            return (getOwner() == null ? other.getOwner() == null : getOwner().equals(other.getOwner())) &&
                    getName().equals(other.getName()) &&
                    getSignature().equals(other.getSignature()) &&
                    Intrinsics.areEqual(getBoundReceiver(), other.getBoundReceiver());
@@ -99,7 +99,7 @@ public class FunctionReference extends CallableReference implements FunctionBase
 
     @Override
     public int hashCode() {
-        return (getOwner().hashCode() * 31 + getName().hashCode()) * 31 + getSignature().hashCode();
+        return ((getOwner() == null ? 0 : getOwner().hashCode() * 31) + getName().hashCode()) * 31 + getSignature().hashCode();
     }
 
     @Override

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -2395,6 +2395,18 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("equalsHashCode.kt")
+                public void testEqualsHashCode() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/equalsHashCode.kt");
+                    try {
+                        doTest(fileName);
+                    }
+                    catch (Throwable ignore) {
+                        return;
+                    }
+                    throw new AssertionError("Looks like this test can be unmuted. Remove IGNORE_BACKEND directive for that.");
+                }
+
                 @TestMetadata("extension.kt")
                 public void testExtension() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/box/callableReference/function/local/extension.kt");