bug#48100: 28.0.50; inserting too many lines into a fresh cpp file breaks the buffer

[Lars Ingebrigtsen <larsi@gnus.org>]

Paul Nelson <ultrono@gmail.com> writes:

> Start from emacs -Q.  Insert sufficiently many lines of C++ code in a
> temporary buffer.  A slightly contrived example:

[...]

> Copy these lines to the kill ring.  Create a new file "test.cpp", and
> paste what was copied.
>
> The first error is that syntax highlighting stops after a certain
> number of lines (in the above example, just before the final line).

I tried this in Emacs 28, and I could not reproduce the reported
behaviour -- this works fine for me.

> Incidentally, "C-u C-M-x" applied to c-guess-basic-syntax gives a long and
> complicated backtrace that starts with:
>
> Debugger entered--Lisp error: (invalid-read-syntax "Expected" "lambda")
>   edebug-syntax-error("Expected" "lambda")

I can reproduce this, though, so I've added Alan to the CCs.

-- 
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