Add a method to MoreTypes that does the same operation as Types.asEle…

…ment, but can be called statically. Then, clean up all of the places that callers to MoreTypes.asTypeElement were passing through a Types instance just for that reason.

-------------
Created by MOE: http://code.google.com/p/moe-java
MOE_MIGRATED_REVID=84753119

common/src/main/java/com/google/auto/common/MoreTypes.java

@@ -15,7 +15,6 @@
  */
 package com.google.auto.common;
 
-import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.collect.Iterables.getOnlyElement;
 import static com.google.common.base.Preconditions.checkState;
@@ -59,7 +58,6 @@
 import javax.lang.model.type.TypeVisitor;
 import javax.lang.model.type.WildcardType;
 import javax.lang.model.util.Elements;
-import javax.lang.model.util.SimpleElementVisitor6;
 import javax.lang.model.util.SimpleTypeVisitor6;
 import javax.lang.model.util.Types;
 
@@ -460,30 +458,48 @@ public Void visitWildcard(WildcardType t, Builder<TypeElement> p) {
     return elements.build();
   }
 
-  public static TypeElement asTypeElement(Types types, TypeMirror mirror) {
-    checkNotNull(types);
-    checkNotNull(mirror);
-    Element element = types.asElement(mirror);
-    checkArgument(element != null);
-    return element.accept(new SimpleElementVisitor6<TypeElement, Void>() {
-      @Override
-      protected TypeElement defaultAction(Element e, Void p) {
-        throw new IllegalArgumentException();
-      }
+  /**
+   * An alternate implementation of {@link Types#asElement} that does not require a {@link Types}
+   * instance with the notable difference that it will throw {@link IllegalArgumentException}
+   * instead of returning null if the {@link TypeMirror} can not be converted to an {@link Element}.
+   *
+   * @throws NullPointerException if {@code typeMirror} is {@code null}
+   * @throws IllegalArgumentException if {@code typeMirror} cannot be converted to an
+   *     {@link Element}
+   */
+  public static Element asElement(TypeMirror typeMirror) {
+    return typeMirror.accept(AS_ELEMENT_VISITOR, null);
+  }
 
-      @Override public TypeElement visitType(TypeElement e, Void p) {
-        return e;
-      }
-    }, null);
+  private static final TypeVisitor<Element, Void> AS_ELEMENT_VISITOR =
+      new SimpleTypeVisitor6<Element, Void>() {
+        @Override protected Element defaultAction(TypeMirror e, Void p) {
+          throw new IllegalArgumentException(e + "cannot be converted to an Element");
+        }
+
+        @Override public Element visitDeclared(DeclaredType t, Void p) {
+          return t.asElement();
+        }
+
+        @Override public Element visitError(ErrorType t, Void p) {
+          return t.asElement();
+        }
+
+        @Override public Element visitTypeVariable(TypeVariable t, Void p) {
+          return t.asElement();
+        }
+      };
+
+  // TODO(gak): consider removing these two methods as they're pretty trivial now
+  public static TypeElement asTypeElement(TypeMirror mirror) {
+    return MoreElements.asType(asElement(mirror));
   }
 
-  public static ImmutableSet<TypeElement> asTypeElements(Types types,
-      Iterable<? extends TypeMirror> mirrors) {
-    checkNotNull(types);
+  public static ImmutableSet<TypeElement> asTypeElements(Iterable<? extends TypeMirror> mirrors) {
     checkNotNull(mirrors);
     ImmutableSet.Builder<TypeElement> builder = ImmutableSet.builder();
     for (TypeMirror mirror : mirrors) {
-      builder.add(asTypeElement(types, mirror));
+      builder.add(asTypeElement(mirror));
     }
     return builder.build();
   }
@@ -716,7 +732,7 @@ public static Optional<DeclaredType> nonObjectSuperclass(final Types types, Elem
         ? Optional.of(MoreTypes.asDeclared(superclass))
         : Optional.<DeclaredType>absent();
   }
-  
+
   /**
    * Resolves a {@link VariableElement} parameter to a method or constructor based on the given
    * container, or a member of a class. For parameters to a method or constructor, the variable's

common/src/test/java/com/google/auto/common/MoreTypesTest.java

@@ -18,6 +18,7 @@
 import static com.google.common.truth.Truth.assertThat;
 import static javax.lang.model.type.TypeKind.NONE;
 import static javax.lang.model.type.TypeKind.VOID;
+import static org.junit.Assert.fail;
 
 import com.google.common.base.Function;
 import com.google.common.base.Optional;
@@ -42,6 +43,7 @@
 import javax.lang.model.element.AnnotationMirror;
 import javax.lang.model.element.Element;
 import javax.lang.model.element.TypeElement;
+import javax.lang.model.element.TypeParameterElement;
 import javax.lang.model.element.VariableElement;
 import javax.lang.model.type.DeclaredType;
 import javax.lang.model.type.ErrorType;
@@ -254,12 +256,34 @@ private static final class ReferencedTypesTestData {
     int[] f11;
     Set<? super String> f12;
   }
-  
+
   private static class Parent<T> {}
   private static class ChildA extends Parent<Number> {}
   private static class ChildB extends Parent<String> {}
   private static class GenericChild<T> extends Parent<T> {}
-
+
+  @Test
+  public void asElement_throws() {
+    TypeMirror javaDotLang =
+        compilationRule.getElements().getPackageElement("java.lang").asType();
+    try {
+      MoreTypes.asElement(javaDotLang);
+      fail();
+    } catch (IllegalArgumentException expected) {}
+
+  }
+
+  @Test
+  public void asElement() {
+    Elements elements = compilationRule.getElements();
+    TypeElement stringElement = elements.getTypeElement("java.lang.String");
+    assertThat(MoreTypes.asElement(stringElement.asType())).isEqualTo(stringElement);
+    TypeParameterElement setParameterElement = Iterables.getOnlyElement(
+        compilationRule.getElements().getTypeElement("java.util.Set").getTypeParameters());
+    assertThat(MoreTypes.asElement(setParameterElement.asType())).isEqualTo(setParameterElement);
+    // we don't test error types because those are very hard to get predictably
+  }
+
   @Test
   public void testNonObjectSuperclass() {
     Types types = compilationRule.getTypes();
@@ -273,10 +297,10 @@ public void testNonObjectSuperclass() {
     TypeElement genericChild = elements.getTypeElement(GenericChild.class.getCanonicalName());
     TypeMirror genericChildOfNumber = types.getDeclaredType(genericChild, numberType);
     TypeMirror genericChildOfInteger = types.getDeclaredType(genericChild, integerType);
-    
+
     assertThat(MoreTypes.nonObjectSuperclass(types, elements, (DeclaredType) parent.asType()))
         .isAbsent();
-    
+
     Optional<DeclaredType> parentOfChildA =
         MoreTypes.nonObjectSuperclass(types, elements, (DeclaredType) childA.asType());
     Optional<DeclaredType> parentOfChildB =
@@ -286,7 +310,7 @@ public void testNonObjectSuperclass() {
     Optional<DeclaredType> parentOfGenericChildOfNumber =
         MoreTypes.nonObjectSuperclass(types, elements, (DeclaredType) genericChildOfNumber);
     Optional<DeclaredType> parentOfGenericChildOfInteger =
-        MoreTypes.nonObjectSuperclass(types, elements, (DeclaredType) genericChildOfInteger);    
+        MoreTypes.nonObjectSuperclass(types, elements, (DeclaredType) genericChildOfInteger);
 
     EquivalenceTester<TypeMirror> tester = EquivalenceTester.<TypeMirror>of(MoreTypes.equivalence())
           .addEquivalenceGroup(parentOfChildA.get(),

value/src/main/java/com/google/auto/value/processor/BuilderSpec.java

@@ -59,7 +59,6 @@ class BuilderSpec {
   private static final Equivalence<TypeMirror> TYPE_EQUIVALENCE = MoreTypes.equivalence();
 
   private final TypeElement autoValueClass;
-  private final Types typeUtils;
   private final Elements elementUtils;
   private final ErrorReporter errorReporter;
 
@@ -68,7 +67,6 @@ class BuilderSpec {
       ProcessingEnvironment processingEnv,
       ErrorReporter errorReporter) {
     this.autoValueClass = autoValueClass;
-    this.typeUtils = processingEnv.getTypeUtils();
     this.elementUtils = processingEnv.getElementUtils();
     this.errorReporter = errorReporter;
   }
@@ -431,7 +429,7 @@ private void addAbstractMethods(
       return;
     }
 
-    TypeElement typeElement = MoreTypes.asTypeElement(typeUtils, typeMirror);
+    TypeElement typeElement = MoreTypes.asTypeElement(typeMirror);
     addAbstractMethods(typeElement.getSuperclass(), abstractMethods);
     for (TypeMirror interfaceMirror : typeElement.getInterfaces()) {
       addAbstractMethods(interfaceMirror, abstractMethods);