Do not report ACCIDENTAL_OVERRIDE on SAM adapters and such

compiler/backend/src/org/jetbrains/jet/codegen/state/GenerationState.java

@@ -36,6 +36,7 @@ import org.jetbrains.jet.lang.resolve.BindingContext;
 import org.jetbrains.jet.lang.resolve.BindingContextUtils;
 import org.jetbrains.jet.lang.resolve.BindingTrace;
 import org.jetbrains.jet.lang.resolve.DelegatingBindingTrace;
+import org.jetbrains.jet.lang.resolve.calls.CallResolverUtil;
 import org.jetbrains.jet.lang.resolve.java.diagnostics.*;
 import org.jetbrains.jet.lang.resolve.java.jvmSignature.JvmMethodSignature;
 import org.jetbrains.jet.lang.resolve.name.FqName;
@@ -334,6 +335,11 @@ public class GenerationState {
                     // a member of super is not visible: no override
                     continue;
                 }
+                if (member instanceof CallableMemberDescriptor &&
+                    CallResolverUtil.isOrOverridesSynthesized((CallableMemberDescriptor) member)) {
+                    // if a signature clashes with a SAM-adapter or something like that, there's no harm
+                    continue;
+                }
                 if (member instanceof PropertyDescriptor) {
                     PropertyDescriptor propertyDescriptor = (PropertyDescriptor) member;
 

compiler/testData/diagnostics/tests/duplicateJvmSignature/accidentalOverrides/phantomClashWithSamAdapter.kt

@@ -0,0 +1,27 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+// FILE: p/Sam.java
+
+package p;
+
+public interface Sam {
+    void sam();
+}
+
+// FILE: p/Foo.java
+
+package p;
+
+public class Foo {
+    public void foo(Sam sam);
+}
+
+// FILE: k.kt
+
+import p.*
+
+// to have enough fake overrides
+open class K0 : Foo()
+
+class K : K0() {
+    fun foo(f: () -> Unit) {}
+}

compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java

@@ -2593,6 +2593,11 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                     doTest("compiler/testData/diagnostics/tests/duplicateJvmSignature/accidentalOverrides/genericClassFunction.kt");
                 }
                 
+                @TestMetadata("phantomClashWithSamAdapter.kt")
+                public void testPhantomClashWithSamAdapter() throws Exception {
+                    doTest("compiler/testData/diagnostics/tests/duplicateJvmSignature/accidentalOverrides/phantomClashWithSamAdapter.kt");
+                }
+                
                 @TestMetadata("privateClassFunctionOverriddenByProperty.kt")
                 public void testPrivateClassFunctionOverriddenByProperty() throws Exception {
                     doTest("compiler/testData/diagnostics/tests/duplicateJvmSignature/accidentalOverrides/privateClassFunctionOverriddenByProperty.kt");