Fix right assignment token management

Author: kddnewton

lib/syntax_tree/parser.rb

@@ -910,7 +910,12 @@ def on_case(value, consequent)
           location: keyword.location.to(consequent.location)
         )
       else
-        operator = find_token(Kw, "in", consume: false) || find_token(Op, "=>")
+        operator =
+          if (keyword = find_token(Kw, "in", consume: false))
+            tokens.delete(keyword)
+          else
+            find_token(Op, "=>")
+          end
 
         RAssign.new(
           value: value,

test/fixtures/rassign.rb

@@ -20,3 +20,6 @@
   ConstantConstantConstant,
   ConstantConstantConstant
 ]
+%
+a in Integer
+b => [Integer => c]