Display linear/multiplicity arrows correctly (#1238)

Previously we were ignoring multiplicity and displayed
a %1 -> b as a -> b.

(cherry picked from commit b4b4d896d2d68d6c48e7db7bfe95c185ca0709cb)

4 files changed, 112 insertions, 0 deletions

diff --git a/latex-test/ref/LinearTypes/LinearTypes.tex b/latex-test/ref/LinearTypes/LinearTypes.tex
new file mode 100644
index 00000000..cb583ca8
--- /dev/null
+++ b/latex-test/ref/LinearTypes/LinearTypes.tex
@@ -0,0 +1,30 @@
+\haddockmoduleheading{LinearTypes}
+\label{module:LinearTypes}
+\haddockbeginheader
+{\haddockverb\begin{verbatim}
+module LinearTypes (
+    unrestricted, linear, poly
+  ) where\end{verbatim}}
+\haddockendheader
+
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+unrestricted :: a -> b
+\end{tabular}]
+{\haddockbegindoc
+Does something unrestricted.\par}
+\end{haddockdesc}
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+linear :: a {\char '45}1 -> b
+\end{tabular}]
+{\haddockbegindoc
+Does something linear.\par}
+\end{haddockdesc}
+\begin{haddockdesc}
+\item[\begin{tabular}{@{}l}
+poly :: a {\char '45}m -> b
+\end{tabular}]
+{\haddockbegindoc
+Does something polymorphic.\par}
+\end{haddockdesc}
\ No newline at end of file
diff --git a/latex-test/ref/LinearTypes/haddock.sty b/latex-test/ref/LinearTypes/haddock.sty
new file mode 100644
index 00000000..6e031a98
--- /dev/null
+++ b/latex-test/ref/LinearTypes/haddock.sty
@@ -0,0 +1,57 @@
+% Default Haddock style definitions.  To use your own style, invoke
+% Haddock with the option --latex-style=mystyle.
+
+\usepackage{tabulary} % see below
+
+% make hyperlinks in the PDF, and add an expandabale index
+\usepackage[pdftex,bookmarks=true]{hyperref}
+
+\newenvironment{haddocktitle}
+  {\begin{center}\bgroup\large\bfseries}
+  {\egroup\end{center}}
+\newenvironment{haddockprologue}{\vspace{1in}}{}
+
+\newcommand{\haddockmoduleheading}[1]{\chapter{\texttt{#1}}}
+
+\newcommand{\haddockbeginheader}{\hrulefill}
+\newcommand{\haddockendheader}{\noindent\hrulefill}
+
+% a little gap before the ``Methods'' header
+\newcommand{\haddockpremethods}{\vspace{2ex}}
+
+% inserted before \\begin{verbatim}
+\newcommand{\haddockverb}{\small}
+
+% an identifier: add an index entry
+\newcommand{\haddockid}[1]{\haddocktt{#1}\index{#1@\texttt{#1}}}
+
+% The tabulary environment lets us have a column that takes up ``the
+% rest of the space''.  Unfortunately it doesn't allow
+% the \end{tabulary} to be in the expansion of a macro, it must appear
+% literally in the document text, so Haddock inserts
+% the \end{tabulary} itself.
+\newcommand{\haddockbeginconstrs}{\begin{tabulary}{\linewidth}{@{}llJ@{}}}
+\newcommand{\haddockbeginargs}{\begin{tabulary}{\linewidth}{@{}llJ@{}}}
+
+\newcommand{\haddocktt}[1]{{\small \texttt{#1}}}
+\newcommand{\haddockdecltt}[1]{{\small\bfseries \texttt{#1}}}
+
+\makeatletter
+\newenvironment{haddockdesc}
+               {\list{}{\labelwidth\z@ \itemindent-\leftmargin
+                        \let\makelabel\haddocklabel}}
+               {\endlist}
+\newcommand*\haddocklabel[1]{\hspace\labelsep\haddockdecltt{#1}}
+\makeatother
+
+% after a declaration, start a new line for the documentation.
+% Otherwise, the documentation starts right after the declaration,
+% because we're using the list environment and the declaration is the
+% ``label''.  I tried making this newline part of the label, but
+% couldn't get that to work reliably (the space seemed to stretch
+% sometimes).
+\newcommand{\haddockbegindoc}{\hfill\\[1ex]}
+
+% spacing between paragraphs and no \parindent looks better
+\parskip=10pt plus2pt minus2pt
+\setlength{\parindent}{0cm}
diff --git a/latex-test/ref/LinearTypes/main.tex b/latex-test/ref/LinearTypes/main.tex
new file mode 100644
index 00000000..655261c3
--- /dev/null
+++ b/latex-test/ref/LinearTypes/main.tex
@@ -0,0 +1,11 @@
+\documentclass{book}
+\usepackage{haddock}
+\begin{document}
+\begin{titlepage}
+\begin{haddocktitle}
+
+\end{haddocktitle}
+\end{titlepage}
+\tableofcontents
+\input{LinearTypes}
+\end{document}
\ No newline at end of file
diff --git a/latex-test/src/LinearTypes/LinearTypes.hs b/latex-test/src/LinearTypes/LinearTypes.hs
new file mode 100644
index 00000000..cb4eb138
--- /dev/null
+++ b/latex-test/src/LinearTypes/LinearTypes.hs
@@ -0,0 +1,14 @@
+{-# LANGUAGE LinearTypes #-}
+module LinearTypes where
+
+-- | Does something unrestricted.
+unrestricted :: a -> b
+unrestricted = undefined
+
+-- | Does something linear.
+linear :: a %1 -> b
+linear = linear
+
+-- | Does something polymorphic.
+poly :: a %m -> b
+poly = poly