at runtime
matchContextErrString (StmtCtxt (ParStmtCtxt c))   = matchContextErrString (StmtCtxt c)
matchContex
matchContextErrString (StmtCtxt (ParStmtCtxt c))   = matchContextErrString (StmtCtxt c)
matchContextErrString (StmtCtxt (ParStmtCtxt c))   = matchContextErrString (StmtCtxt c)