Ensure that types are substituted correctly in property builders.

The regression test tickles a bug in Eclipse so this change introduces a new place to put tests like that. I don't know how to work around the Eclipse failure, which is a NullPointerException inside Types.asMemberOf.

RELNOTES=Property builders now work correctly when their actual return type is different from the corresponding property type because of type variable substitution.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=271621735

3 files changed, 77 insertions, 2 deletions

diff --git a/value/src/it/functional/src/test/java/com/google/auto/value/AutoValueNotEclipseTest.java b/value/src/it/functional/src/test/java/com/google/auto/value/AutoValueNotEclipseTest.java
new file mode 100644
index 00000000..17cd6352
--- /dev/null
+++ b/value/src/it/functional/src/test/java/com/google/auto/value/AutoValueNotEclipseTest.java
@@ -0,0 +1,65 @@
+/*
+ * Copyright 2019 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.google.auto.value;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/**
+ * Like {@link AutoValueTest}, but with code that doesn't build with at least some versions of
+ * Eclipse, and should therefore not be included in {@link CompileWithEclipseTest}. (The latter is
+ * not currently present in the open-source build.)
+ */
+@RunWith(JUnit4.class)
+public class AutoValueNotEclipseTest {
+  interface ImmutableListOf<T> {
+    ImmutableList<T> list();
+  }
+
+  // This provoked the following with the Eclipse compiler:
+  // java.lang.NullPointerException
+  //   at org.eclipse.jdt.internal.compiler.lookup.ParameterizedTypeBinding.readableName(ParameterizedTypeBinding.java:1021)
+  //   at org.eclipse.jdt.internal.compiler.apt.model.DeclaredTypeImpl.toString(DeclaredTypeImpl.java:118)
+  //   at java.lang.String.valueOf(String.java:2996)
+  //   at java.lang.StringBuilder.append(StringBuilder.java:131)
+  //   at org.eclipse.jdt.internal.compiler.apt.model.TypesImpl.asMemberOf(TypesImpl.java:130)
+  //   at com.google.auto.value.processor.EclipseHack.methodReturnType(EclipseHack.java:124)
+  //   at com.google.auto.value.processor.TypeVariables.lambda$rewriteReturnTypes$1(TypeVariables.java:106)
+  @AutoValue
+  abstract static class PropertyBuilderInheritsType implements ImmutableListOf<String> {
+    static Builder builder() {
+      return new AutoValue_AutoValueNotEclipseTest_PropertyBuilderInheritsType.Builder();
+    }
+
+    @AutoValue.Builder
+    abstract static class Builder {
+      abstract ImmutableList.Builder<String> listBuilder();
+      abstract PropertyBuilderInheritsType build();
+    }
+  }
+
+  @Test
+  public void propertyBuilderInheritsType() {
+    PropertyBuilderInheritsType.Builder builder = PropertyBuilderInheritsType.builder();
+    builder.listBuilder().add("foo", "bar");
+    PropertyBuilderInheritsType x = builder.build();
+    assertThat(x.list()).containsExactly("foo", "bar").inOrder();
+  }
+}
diff --git a/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java b/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java
index 94e26ef0..3b3799b4 100644
--- a/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java
+++ b/value/src/main/java/com/google/auto/value/processor/BuilderMethodClassifier.java
@@ -274,7 +274,13 @@ class BuilderMethodClassifier {
       if (getterToPropertyName.containsValue(property)) {
         PropertyBuilderClassifier propertyBuilderClassifier =
             new PropertyBuilderClassifier(
-                errorReporter, typeUtils, elementUtils, this, getterToPropertyName, eclipseHack);
+                errorReporter,
+                typeUtils,
+                elementUtils,
+                this,
+                getterToPropertyName,
+                getterToPropertyType,
+                eclipseHack);
         Optional<PropertyBuilder> propertyBuilder =
             propertyBuilderClassifier.makePropertyBuilder(method, property);
         if (propertyBuilder.isPresent()) {
diff --git a/value/src/main/java/com/google/auto/value/processor/PropertyBuilderClassifier.java b/value/src/main/java/com/google/auto/value/processor/PropertyBuilderClassifier.java
index 41080730..3b8592b8 100644
--- a/value/src/main/java/com/google/auto/value/processor/PropertyBuilderClassifier.java
+++ b/value/src/main/java/com/google/auto/value/processor/PropertyBuilderClassifier.java
@@ -19,6 +19,7 @@ import com.google.auto.common.MoreElements;
 import com.google.auto.common.MoreTypes;
 import com.google.common.collect.ImmutableBiMap;
 import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
 import java.util.LinkedHashMap;
 import java.util.List;
@@ -52,6 +53,7 @@ class PropertyBuilderClassifier {
   private final Elements elementUtils;
   private final BuilderMethodClassifier builderMethodClassifier;
   private final ImmutableBiMap<ExecutableElement, String> getterToPropertyName;
+  private final ImmutableMap<ExecutableElement, TypeMirror> getterToPropertyType;
   private final EclipseHack eclipseHack;
 
   PropertyBuilderClassifier(
@@ -60,12 +62,14 @@ class PropertyBuilderClassifier {
       Elements elementUtils,
       BuilderMethodClassifier builderMethodClassifier,
       ImmutableBiMap<ExecutableElement, String> getterToPropertyName,
+      ImmutableMap<ExecutableElement, TypeMirror> getterToPropertyType,
       EclipseHack eclipseHack) {
     this.errorReporter = errorReporter;
     this.typeUtils = typeUtils;
     this.elementUtils = elementUtils;
     this.builderMethodClassifier = builderMethodClassifier;
     this.getterToPropertyName = getterToPropertyName;
+    this.getterToPropertyType = getterToPropertyType;
     this.eclipseHack = eclipseHack;
   }
 
@@ -207,7 +211,7 @@ class PropertyBuilderClassifier {
     Map<String, ExecutableElement> barBuilderNoArgMethods = noArgMethodsOf(barBuilderTypeElement);
 
     ExecutableElement barGetter = getterToPropertyName.inverse().get(property);
-    TypeMirror barTypeMirror = barGetter.getReturnType();
+    TypeMirror barTypeMirror = getterToPropertyType.get(barGetter);
     if (barTypeMirror.getKind() != TypeKind.DECLARED) {
       errorReporter.reportError(
           "Method looks like a property builder, but the type of property "