Add CodegenUtil.isNullableType(), fix assertions

JetType.isNullable() is not accurate when the type denotes a type parameter:
a parameter can be not null (isNullable=false), but its upper bound can be
nullable (<T: Any?>), so null may appear in the value of such type. Therefore
it's preferred to use a special check (isNullableType()) in codegen from now on

Do not generate assertion for parameters of not-null types which have a
nullable upper bound + the same with Java method calls

Also fix Intrinsics class internal name in tests

 #KT-3313 Fixed

compiler/backend/src/org/jetbrains/jet/codegen/AsmUtil.java

@@ -47,6 +47,7 @@ import java.util.Set;
 
 import static org.jetbrains.asm4.Opcodes.*;
 import static org.jetbrains.jet.codegen.CodegenUtil.isInterface;
+import static org.jetbrains.jet.codegen.CodegenUtil.isNullableType;
 import static org.jetbrains.jet.lang.resolve.DescriptorUtils.isClassObject;
 import static org.jetbrains.jet.lang.resolve.java.AsmTypeConstants.JAVA_STRING_TYPE;
 
@@ -532,7 +533,7 @@ public class AsmUtil {
 
         for (ValueParameterDescriptor parameter : descriptor.getValueParameters()) {
             JetType type = parameter.getReturnType();
-            if (type == null || type.isNullable()) continue;
+            if (type == null || isNullableType(type)) continue;
 
             int index = frameMap.getIndex(parameter);
             Type asmType = state.getTypeMapper().mapReturnType(type);
@@ -574,7 +575,7 @@ public class AsmUtil {
         if (!isDeclaredInJava(descriptor, state.getBindingContext())) return;
 
         JetType type = descriptor.getReturnType();
-        if (type == null || type.isNullable()) return;
+        if (type == null || isNullableType(type)) return;
 
         Type asmType = state.getTypeMapper().mapReturnType(type);
         if (asmType.getSort() == Type.OBJECT || asmType.getSort() == Type.ARRAY) {

compiler/backend/src/org/jetbrains/jet/codegen/CodegenUtil.java

@@ -41,6 +41,7 @@ import org.jetbrains.jet.lang.resolve.java.JvmStdlibNames;
 import org.jetbrains.jet.lang.resolve.name.Name;
 import org.jetbrains.jet.lang.resolve.scopes.JetScope;
 import org.jetbrains.jet.lang.types.JetType;
+import org.jetbrains.jet.lang.types.TypeUtils;
 import org.jetbrains.jet.lang.types.lang.KotlinBuiltIns;
 
 import java.util.*;
@@ -278,5 +279,16 @@ public class CodegenUtil {
                         return ((MemberDescriptor) declaration).getModality() == ABSTRACT;
                     }
                 });
-}
+    }
+
+    /**
+     * A work-around of the generic nullability problem in the type checker
+     * @return true if a value of this type can be null
+     */
+    public static boolean isNullableType(@NotNull JetType type) {
+        if (type.getConstructor().getDeclarationDescriptor() instanceof TypeParameterDescriptor) {
+            return TypeUtils.hasNullableSuperType(type);
+        }
+        return type.isNullable();
+    }
 }

compiler/testData/codegen/box/functions/kt3313.kt

@@ -0,0 +1,7 @@
+fun foo<T>(t: T) {
+}
+
+fun box(): String {
+    foo(null)
+    return "OK"
+}

compiler/testData/codegen/notNullAssertions/assertionForNotNullTypeParam.kt

@@ -0,0 +1 @@
+fun foo<T : Any>(t: T) = t

compiler/testData/codegen/notNullAssertions/noAssertionForNullableGenericMethod.kt

@@ -0,0 +1,3 @@
+fun foo<T>(a: List<T>) {
+    val t: T = a.get(0)
+}

compiler/tests/org/jetbrains/jet/codegen/GenerateNotNullAssertionsTest.java

@@ -18,6 +18,7 @@ package org.jetbrains.jet.codegen;
 
 import com.intellij.openapi.util.io.FileUtil;
 import com.intellij.openapi.util.text.StringUtil;
+import jet.runtime.Intrinsics;
 import org.jetbrains.asm4.ClassReader;
 import org.jetbrains.asm4.ClassVisitor;
 import org.jetbrains.asm4.MethodVisitor;
@@ -29,6 +30,7 @@ import org.jetbrains.jet.cli.jvm.JVMConfigurationKeys;
 import org.jetbrains.jet.cli.jvm.compiler.CompileEnvironmentUtil;
 import org.jetbrains.jet.cli.jvm.compiler.JetCoreEnvironment;
 import org.jetbrains.jet.config.CompilerConfiguration;
+import org.jetbrains.jet.lang.resolve.java.JvmClassName;
 import org.jetbrains.jet.lang.resolve.java.PackageClassUtils;
 import org.jetbrains.jet.lang.resolve.name.FqName;
 
@@ -138,11 +140,28 @@ public class GenerateNotNullAssertionsTest extends CodegenTestCase {
         assertEquals(3, StringUtil.getOccurrenceCount(text, "checkParameterIsNotNull"));
     }
 
+    public void testAssertionForNotNullTypeParam() {
+        setUpEnvironment(true, true);
+
+        loadFile("notNullAssertions/assertionForNotNullTypeParam.kt");
+
+        assertTrue(generateToText().contains("checkParameterIsNotNull"));
+    }
+
+    public void testNoAssertionForNullableGenericMethod() {
+        setUpEnvironment(true, false);
+
+        loadFile("notNullAssertions/noAssertionForNullableGenericMethod.kt");
+
+        assertNoIntrinsicsMethodIsCalled(PackageClassUtils.getPackageClassName(FqName.ROOT));
+    }
 
     private void assertNoIntrinsicsMethodIsCalled(String className) {
         ClassFileFactory classes = generateClassesInFile();
         ClassReader reader = new ClassReader(classes.asBytes(className + ".class"));
 
+        final String intrinsics = JvmClassName.byFqNameWithoutInnerClasses(Intrinsics.class.getName()).getInternalName();
+
         reader.accept(new ClassVisitor(Opcodes.ASM4) {
             @Override
             public MethodVisitor visitMethod(
@@ -152,8 +171,8 @@ public class GenerateNotNullAssertionsTest extends CodegenTestCase {
                     @Override
                     public void visitMethodInsn(int opcode, String owner, String name, String desc) {
                         assertFalse(
-                                "jet/Intrinsics method is called: " + name + desc + "  Caller: " + callerName + callerDesc,
-                                "jet/Intrinsics".equals(owner)
+                                "Intrinsics method is called: " + name + desc + "  Caller: " + callerName + callerDesc,
+                                intrinsics.equals(owner)
                         );
                     }
                 };

compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxCodegenTestGenerated.java

@@ -1736,6 +1736,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             blackBoxFileByFullPath("compiler/testData/codegen/box/functions/kt2929.kt");
         }
         
+        @TestMetadata("kt3313.kt")
+        public void testKt3313() throws Exception {
+            blackBoxFileByFullPath("compiler/testData/codegen/box/functions/kt3313.kt");
+        }
+        
         @TestMetadata("kt395.kt")
         public void testKt395() throws Exception {
             blackBoxFileByFullPath("compiler/testData/codegen/box/functions/kt395.kt");