Do not raise when default is boolean and option is required

Author: rafaelfranca

lib/thor/parser/option.rb

@@ -116,7 +116,7 @@ def validate_default_type!
                      when nil
                        return
                      when TrueClass, FalseClass
-                       :boolean
+                       required? ? :string : :boolean
                      when Numeric
                        :numeric
                      when Symbol

spec/parser/option_spec.rb

@@ -153,6 +153,12 @@ def option(name, options = {})
     end.to raise_error(ArgumentError, "An option cannot be boolean and required.")
   end
 
+  it "does not raises an error if default is a boolean and it is required" do
+    expect do
+      option("foo", :required => true, :default => true)
+    end.not_to raise_error
+  end
+
   it "allows type predicates" do
     expect(parse(:foo, :string)).to be_string
     expect(parse(:foo, :boolean)).to be_boolean