Provide a serialized graph of subtypes for ambiguation

This is stored as a separate list of edges instead of a list of supertypes per ObjectType in order to make it easier to store additional graphs in the future, which may need a different definition of "supertype".

PiperOrigin-RevId: 326115960

Author: lauraharker

src/com/google/javascript/jscomp/colors/ObjectColor.java

@@ -18,6 +18,7 @@
 
 import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableList;
 import javax.annotation.Nullable;
 
 /**
@@ -57,6 +58,10 @@ public ImmutableCollection<Color> getAlternates() {
   @Nullable
   public abstract Color getInstanceColor();
 
+  // List of other colors directly above this in the subtyping graph for the purposes of property
+  // (dis)ambiguation.
+  public abstract ImmutableList<Color> getDisambiguationSupertypes();
+
   @Override
   public abstract boolean isInvalidating();
 
@@ -69,6 +74,8 @@ public abstract static class Builder {
 
     public abstract Builder setInvalidating(boolean value);
 
+    public abstract Builder setDisambiguationSupertypes(ImmutableList<Color> supertypes);
+
     public abstract Builder setPrototype(Color prototype);
 
     public abstract Builder setInstanceColor(Color instanceColor);
@@ -77,6 +84,8 @@ public abstract static class Builder {
   }
 
   public static Builder builder() {
-    return new AutoValue_ObjectColor.Builder().setInvalidating(false);
+    return new AutoValue_ObjectColor.Builder()
+        .setInvalidating(false)
+        .setDisambiguationSupertypes(ImmutableList.of());
   }
 }

src/com/google/javascript/jscomp/testing/ColorSubject.java

@@ -21,6 +21,7 @@
 import com.google.common.truth.FailureMetadata;
 import com.google.common.truth.Subject;
 import com.google.javascript.jscomp.colors.Color;
+import com.google.javascript.jscomp.colors.ObjectColor;
 import javax.annotation.Nullable;
 
 /** Subject for {@link Color} */
@@ -75,4 +76,12 @@ public void hasAlternates(Color... alternates) {
         // cast to Object[] to suppress warning about varargs vs. non-varargs call confusion
         .containsExactly((Object[]) alternates);
   }
+
+  public void hasDisambiguationSupertypes(Color... alternates) {
+    isObject();
+    check("getDirectSupertypes().containsExactly()")
+        .that(((ObjectColor) actualNonNull()).getDisambiguationSupertypes())
+        // cast to Object[] to suppress warning about varargs vs. non-varargs call confusion
+        .containsExactly((Object[]) alternates);
+  }
 }