        let newNode = ASTUtil.buildQName newName $ SrcLoc.SrcLoc
              (SrcLoc.srcSpanFilename span)
              (SrcLoc.srcSpanStartLine span)
              (SrcLoc.srcSpanStartColumn span)
        let newRewrite = ASTUtil.Rewrite
              (SrcLoc.srcInfoSpan $ Syntax.ann node)
              (length newName - length oldName)
        rewrites <- get
        put $ newRewrite : rewrites