code: private SemanticType checkVariable(Expr.VariableAccess expr, Environment environment) {
  		Decl.Variable var = expr.getVariableDeclaration();
  		return environment.getType(var);
  	}
docs: Check the type of a given variable access. This is straightforward since the
  determine is fully determined by the declared type for the variable in
  question.
  
  @param expr
  @return