[LyX/master] PassThru paragraphs have latex_language; consider this when checking previous language

[Juergen Spitzmueller]

commit 15df033bcec5aa65cdb26b7f31b9082f3f7e05da
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Sun Apr 29 13:18:05 2018 +0200

    PassThru paragraphs have latex_language; consider this when checking
    previous language
    
    Fixes: #10793.
---
 src/output_latex.cpp |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/output_latex.cpp b/src/output_latex.cpp
index c36ed25..25ec597 100644
--- a/src/output_latex.cpp
+++ b/src/output_latex.cpp
@@ -790,6 +790,9 @@ void TeXOnePar(Buffer const & buf,
        // environment with nesting depth greater than (or equal to, but with
        // a different layout) the current one. If there is no previous
        // paragraph, the previous language is the outer language.
+       // Note further that we take the outer language also if the prior par
+       // is PassThru, since in that case it has latex_language, and all 
secondary
+       // languages have been closed (#10793).
        bool const use_prev_env_language = state->prev_env_language_ != 0
                        && priorpar
                        && priorpar->layout().isEnvironment()
@@ -797,12 +800,11 @@ void TeXOnePar(Buffer const & buf,
                            || (priorpar->getDepth() == par.getDepth()
                                    && priorpar->layout() != par.layout()));
        Language const * const prev_language =
-               (pit != 0)
+               (priorpar && !priorpar->isPassThru())
                ? (use_prev_env_language ? state->prev_env_language_
                                         : priorpar->getParLanguage(bparams))
                : outer_language;
 
-
        bool const use_polyglossia = runparams.use_polyglossia;
        string const par_lang = use_polyglossia ?
                getPolyglossiaEnvName(par_language): par_language->babel();