Don't emit @SafeVarargs for reifiable types

processor/src/main/java/io/norberg/automatter/processor/AutoMatterProcessor.java

@@ -29,6 +29,8 @@
 import com.squareup.javapoet.WildcardTypeName;
 import io.norberg.automatter.AutoMatter;
 import java.io.IOException;
+import java.lang.reflect.Parameter;
+import java.lang.reflect.ParameterizedType;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -43,6 +45,7 @@
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.TreeSet;
+import java.util.function.Function;
 import java.util.stream.Stream;
 import javax.annotation.processing.AbstractProcessor;
 import javax.annotation.processing.Filer;
@@ -524,7 +527,9 @@ private MethodSpec collectionVarargSetter(final Descriptor d, final ExecutableEl
         .varargs()
         .returns(builderType(d));
 
-    ensureSafeVarargs(setter);
+    if (!isReifiable(itemType)) {
+      ensureSafeVarargs(setter);
+    }
 
     collectionNullGuard(setter, field);
 
@@ -533,7 +538,6 @@ private MethodSpec collectionVarargSetter(final Descriptor d, final ExecutableEl
   }
 
   private void ensureSafeVarargs(MethodSpec.Builder setter) {
-    // TODO: Add SafeVarargs annotation only for non-reifiable types.
     AnnotationSpec safeVarargsAnnotation = AnnotationSpec.builder(SafeVarargs.class).build();
 
     setter
@@ -1433,6 +1437,35 @@ private static String capitalizeFirstLetter(String s) {
     return s.substring(0, 1).toUpperCase() + (s.length() > 1 ? s.substring(1) : "");
   }
 
+  private static boolean isUnboundedWildcard(TypeName type) {
+    if (type instanceof WildcardTypeName) {
+      WildcardTypeName t = (WildcardTypeName) type;
+      return t.lowerBounds.isEmpty() && t.upperBounds.stream().allMatch(bound -> bound.equals(TypeName.OBJECT));
+    }
+    return false;
+  }
+
+  public static boolean isReifiable(TypeName type) {
+    if (type.isPrimitive()) return true;
+    if (type.isBoxedPrimitive()) return true;
+
+    // TODO: handle nested types, per JLS §4.7
+    // JavaPoet does not expose ParameterizedTypeName's enclosing type,
+    // so we can't verify that the enclosing type is reifiable.
+
+    if (type instanceof ParameterizedTypeName) {
+      ParameterizedTypeName parameterized = (ParameterizedTypeName) type;
+      return parameterized.typeArguments.stream().allMatch(AutoMatterProcessor::isUnboundedWildcard);
+    } else if (type instanceof ArrayTypeName) {
+      ArrayTypeName array = (ArrayTypeName) type;
+      return isReifiable(array.componentType);
+    } else if (type instanceof ClassName) {
+      return true;
+    }
+
+    return false;
+  }
+
   @Override
   public SourceVersion getSupportedSourceVersion() {
     return SourceVersion.latestSupported();

processor/src/test/java/io/norberg/automatter/AutoMatterProcessorTest.java

@@ -5,14 +5,23 @@
 import static com.google.testing.compile.Compiler.javac;
 import static com.google.testing.compile.JavaSourceSubjectFactory.javaSource;
 import static com.google.testing.compile.JavaSourcesSubjectFactory.javaSources;
+import static com.squareup.javapoet.WildcardTypeName.subtypeOf;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.common.io.Resources;
 import com.google.testing.compile.Compilation;
 import com.google.testing.compile.JavaFileObjects;
+import com.squareup.javapoet.ArrayTypeName;
+import com.squareup.javapoet.ClassName;
+import com.squareup.javapoet.ParameterizedTypeName;
+import com.squareup.javapoet.TypeName;
+import com.squareup.javapoet.WildcardTypeName;
 import io.norberg.automatter.processor.AutoMatterProcessor;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.util.List;
 import java.util.Set;
 import java.util.stream.Collectors;
 import javax.tools.Diagnostic;
@@ -420,4 +429,28 @@ private boolean hasJutOptional() {
       return false;
     }
   }
+
+  private TypeName[] wildcards(final int size) {
+    final WildcardTypeName wildcard = subtypeOf(ClassName.get(Object.class));
+    final TypeName[] wildcards = new TypeName[size];
+    for (int i = 0; i < size; i++) {
+      wildcards[i] = wildcard;
+    }
+    return wildcards;
+  }
+
+  @Test
+  public void testReifiable() {
+    ParameterizedTypeName listOfObject = ParameterizedTypeName.get(ClassName.get("java.util", "List"), TypeName.OBJECT);
+    assertTrue(AutoMatterProcessor.isReifiable(TypeName.BOOLEAN));
+    assertTrue(AutoMatterProcessor.isReifiable(TypeName.get(String.class)));
+    assertTrue(AutoMatterProcessor.isReifiable(ClassName.get("java.util", "List")));
+    assertTrue(AutoMatterProcessor.isReifiable(ParameterizedTypeName.get(ClassName.get("java.util", "List"), wildcards(1)[0])));
+    assertFalse(AutoMatterProcessor.isReifiable(listOfObject));
+    assertTrue(AutoMatterProcessor.isReifiable(ArrayTypeName.of(String.class)));
+    assertFalse(AutoMatterProcessor.isReifiable(ArrayTypeName.of(listOfObject)));
+
+    // TODO: handle nested classes
+    //assertFalse(AutoMatterProcessor.isReifiable(listOfObject.nestedClass("Foo")));
+  }
 }

processor/src/test/resources/expected/CollectionFieldsBuilder.java

@@ -114,9 +114,7 @@ public CollectionFieldsBuilder strings(Iterator<? extends String> strings) {
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final CollectionFieldsBuilder strings(String... strings) {
+  public CollectionFieldsBuilder strings(String... strings) {
     if (strings == null) {
       throw new NullPointerException("strings");
     }
@@ -474,9 +472,7 @@ public CollectionFieldsBuilder numbers(Iterator<? extends Long> numbers) {
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final CollectionFieldsBuilder numbers(Long... numbers) {
+  public CollectionFieldsBuilder numbers(Long... numbers) {
     if (numbers == null) {
       throw new NullPointerException("numbers");
     }
@@ -543,9 +539,7 @@ public CollectionFieldsBuilder sortedNumbers(Iterator<? extends Long> sortedNumb
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final CollectionFieldsBuilder sortedNumbers(Long... sortedNumbers) {
+  public CollectionFieldsBuilder sortedNumbers(Long... sortedNumbers) {
     if (sortedNumbers == null) {
       throw new NullPointerException("sortedNumbers");
     }
@@ -612,9 +606,7 @@ public CollectionFieldsBuilder navigableNumbers(Iterator<? extends Long> navigab
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final CollectionFieldsBuilder navigableNumbers(Long... navigableNumbers) {
+  public CollectionFieldsBuilder navigableNumbers(Long... navigableNumbers) {
     if (navigableNumbers == null) {
       throw new NullPointerException("navigableNumbers");
     }

processor/src/test/resources/expected/CollectionInterfaceFieldBuilder.java

@@ -69,9 +69,7 @@ public CollectionInterfaceFieldBuilder strings(Iterator<? extends String> string
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final CollectionInterfaceFieldBuilder strings(String... strings) {
+  public CollectionInterfaceFieldBuilder strings(String... strings) {
     if (strings == null) {
       throw new NullPointerException("strings");
     }

processor/src/test/resources/expected/NullableCollectionFieldsBuilder.java

@@ -79,9 +79,7 @@ public NullableCollectionFieldsBuilder strings(Iterator<? extends String> string
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final NullableCollectionFieldsBuilder strings(String... strings) {
+  public NullableCollectionFieldsBuilder strings(String... strings) {
     if (strings == null) {
       this.strings = null;
       return this;
@@ -199,9 +197,7 @@ public NullableCollectionFieldsBuilder numbers(Iterator<? extends Long> numbers)
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final NullableCollectionFieldsBuilder numbers(Long... numbers) {
+  public NullableCollectionFieldsBuilder numbers(Long... numbers) {
     if (numbers == null) {
       this.numbers = null;
       return this;

processor/src/test/resources/expected/inheritance/ConcreteExtensionOfGenericParentBuilder.java

@@ -74,9 +74,7 @@ public ConcreteExtensionOfGenericParentBuilder foos(Iterator<? extends Integer>
     return this;
   }
 
-  @SafeVarargs
-  @SuppressWarnings("varargs")
-  public final ConcreteExtensionOfGenericParentBuilder foos(Integer... foos) {
+  public ConcreteExtensionOfGenericParentBuilder foos(Integer... foos) {
     if (foos == null) {
       throw new NullPointerException("foos");
     }