Akim Demaille 8a910107b3 diagnostics: complain about undeclared string tokens ...

String literals, which allow for better error messages, are (too)
liberally accepted by Bison, which might result in silent errors.  For
instance

    %type <exVal> cond "condition"

does not define “condition” as a string alias to 'cond' (nonterminal
symbols do not have string aliases).  It is rather equivalent to

    %nterm <exVal> cond
    %token <exVal> "condition"

i.e., it gives the type 'exVal' to the "condition" token, which was
clearly not the intention.

Introduce -Wdangling-alias to catch this.

* src/complain.h, src/complain.c: Add support for -Wdangling-alias.
(argmatch_warning_args): Sort.
* src/symtab.c (symbol_check_defined): Complain about dangling
aliases.
* doc/bison.texi: Document it.
* tests/input.at (Dangling aliases): New test.

2019-11-17 18:27:42 +01:00

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