Handle inherited fields correctly.

test/inheritance/inherit_fields.wren

@@ -0,0 +1,35 @@
+class Foo {
+  foo(a, b) {
+    _field1 = a
+    _field2 = b
+  }
+
+  fooPrint {
+    io.write(_field1)
+    io.write(_field2)
+  }
+}
+
+class Bar is Foo {
+  bar(a, b) {
+    _field1 = a
+    _field2 = b
+  }
+
+  barPrint {
+    io.write(_field1)
+    io.write(_field2)
+  }
+}
+
+var bar = Bar.new
+bar.foo("foo 1", "foo 2")
+bar.bar("bar 1", "bar 2")
+
+bar.fooPrint
+// expect: foo 1
+// expect: foo 2
+
+bar.barPrint
+// expect: bar 1
+// expect: bar 2

test/inheritance/is.wren

@@ -0,0 +1,16 @@
+class A {}
+class B is A {}
+class C is B {}
+var a = A.new
+var b = B.new
+var c = C.new
+
+io.write(a is A) // expect: true
+io.write(a is B) // expect: false
+io.write(a is C) // expect: false
+io.write(b is A) // expect: true
+io.write(b is B) // expect: true
+io.write(b is C) // expect: false
+io.write(c is A) // expect: true
+io.write(c is B) // expect: true
+io.write(c is C) // expect: true

test/is.wren

@@ -20,24 +20,6 @@ io.write((fn 1) is Object) // expect: true
 io.write("s" is Object) // expect: true
 io.write(123 is Object) // expect: true
 
-// Inheritance.
-class A {}
-class B is A {}
-class C is B {}
-var a = A.new
-var b = B.new
-var c = C.new
-
-io.write(a is A) // expect: true
-io.write(a is B) // expect: false
-io.write(a is C) // expect: false
-io.write(b is A) // expect: true
-io.write(b is B) // expect: true
-io.write(b is C) // expect: false
-io.write(c is A) // expect: true
-io.write(c is B) // expect: true
-io.write(c is C) // expect: true
-
 // TODO(bob): Non-class on RHS.
 // TODO(bob): Precedence and associativity.
 // TODO(bob): Metaclasses ("Num is Class").