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.

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

2 files changed, 12 insertions, 2 deletions

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 "