Correctly remove support for \stackrel.

anntzer · anntzer · commit 759351e3ce7b · 2020-09-20T15:34:10.000+02:00
This was done incompletely in c4d3cd4, after which `\stackrel{x}{y}` just behaved (incorrectly) like `xy`.
diff --git a/lib/matplotlib/_mathtext.py b/lib/matplotlib/_mathtext.py
@@ -2059,7 +2059,6 @@ def __init__(self):
         p.accentprefixed   = Forward()
         p.space            = Forward()
         p.sqrt             = Forward()
-        p.stackrel         = Forward()
         p.start_group      = Forward()
         p.subsuper         = Forward()
         p.subsuperop       = Forward()
@@ -2144,12 +2143,6 @@ def __init__(self):
                | Error(r"Expected \dfrac{num}{den}"))
         )
 
-        p.stackrel      <<= Group(
-            Suppress(Literal(r"\stackrel"))
-            - ((p.required_group + p.required_group)
-               | Error(r"Expected \stackrel{num}{den}"))
-        )
-
         p.binom         <<= Group(
             Suppress(Literal(r"\binom"))
             - ((p.required_group + p.required_group)
@@ -2206,7 +2199,6 @@ def __init__(self):
             | p.group
             | p.frac
             | p.dfrac
-            | p.stackrel
             | p.binom
             | p.genfrac
             | p.sqrt
diff --git a/lib/matplotlib/tests/test_mathtext.py b/lib/matplotlib/tests/test_mathtext.py
@@ -218,8 +218,6 @@ def test_fontinfo():
         (r'$\hspace{foo}$', r'Expected \hspace{n}'),
         (r'$\frac$', r'Expected \frac{num}{den}'),
         (r'$\frac{}{}$', r'Expected \frac{num}{den}'),
-        (r'$\stackrel$', r'Expected \stackrel{num}{den}'),
-        (r'$\stackrel{}{}$', r'Expected \stackrel{num}{den}'),
         (r'$\binom$', r'Expected \binom{num}{den}'),
         (r'$\binom{}{}$', r'Expected \binom{num}{den}'),
         (r'$\genfrac$',
@@ -242,8 +240,6 @@ def test_fontinfo():
         'hspace with invalid value',
         'frac without parameters',
         'frac with empty parameters',
-        'stackrel without parameters',
-        'stackrel with empty parameters',
         'binom without parameters',
         'binom with empty parameters',
         'genfrac without parameters',
