Have IfNode#branches return a nil branch if there is an else ke…

…yword but no body

CHANGELOG.md

@@ -21,6 +21,7 @@
 
 * [#44](https://github.com/rubocop-hq/rubocop-ast/issue/44): **(Breaking)** Use `parser` flag `self.emit_forward_arg = true` by default. ([@marcandre][])
 * [#86](https://github.com/rubocop-hq/rubocop-ast/pull/86): `PairNode#delimiter` and `inverse_delimiter` now accept their argument as a named argument. ([@marcandre][])
+* [#87](https://github.com/rubocop-hq/rubocop-ast/pull/87): **(Potentially breaking)** Have `IfNode#branches` return a `nil` value if source has `else; end` ([@marcandre][])
 
 ## 0.2.0 (2020-07-19)
 

lib/rubocop/ast/node/if_node.rb

@@ -147,7 +147,7 @@ def node_parts
       def branches
         branches = [if_branch]
 
-        return branches unless else_branch
+        return branches unless else?
 
         other_branches = if elsif_conditional?
                            else_branch.branches

spec/rubocop/ast/case_node_spec.rb

@@ -147,5 +147,27 @@
         expect(case_node.branches).to match [nil, be_int_type]
       end
     end
+
+    context 'when compared to an IfNode' do
+      let(:source) { <<~RUBY }
+        case
+        when foo then 1
+        when bar then 2
+        else
+        end
+
+        if foo then 1
+        elsif bar then 2
+        else
+        end
+      RUBY
+
+      let(:case_node) { ast.children.first }
+      let(:if_node) { ast.children.last }
+
+      it 'returns the same' do
+        expect(case_node.branches).to eq if_node.branches
+      end
+    end
   end
 end