Raise an error if variable declaration is incorrect

[user202729]

Brief outline of the proposed feature

Currently if the user try to do

coordinate abc;

or

real \abc=1;

then the bc or =1 will be silently gobbled.

Suggestion: raise an error that the syntax is incorrect (i.e..

We just need to change

\def\tikz@math@@process@vartypes#1#2,{%
    \def\tikz@math@var{#1}%
    \tikz@math@getvarstring{#1}\tikz@math@varstring%
    \ifx\tikz@math@var\tikz@math@stop%
        \let\tikz@math@next=\tikz@math@@@process@vartypes%
    \else%
        \expandafter\tikz@math@setvartype\tikz@math@var\tikz@math@vartype%
        \def\tikz@math@next{\tikz@math@gobblespaces\tikz@math@@process@vartypes}%
    \fi%
    \tikz@math@next%
}%

to check if #2 consist of only spaces.

Usage example

No response