replace dead left-over code by the actually intended fast bint->True/False...

replace dead left-over code by the actually intended fast bint->True/False formatting implementation

Cython/Compiler/PyrexTypes.py

@@ -1765,7 +1765,22 @@ class CBIntType(CIntType):
     exception_check = 1 # for C++ bool
 
     def can_coerce_to_pystring(self, env, format_spec=None):
-        return False
+        return not format_spec
+
+    def to_pystring_function(self, code):
+        if self.to_pyunicode_utility is None:
+            utility_code_name = "__Pyx_PyUnicode_FromBInt_" + self.specialization_name()
+            to_pyunicode_utility = TempitaUtilityCode.load_cached(
+                "CBIntToPyUnicode", "TypeConversion.c", context={
+                    "TRUE_CONST":  code.globalstate.get_py_string_const(StringEncoding.EncodedString("True")).cname,
+                    "FALSE_CONST": code.globalstate.get_py_string_const(StringEncoding.EncodedString("False")).cname,
+                    "TO_PY_FUNCTION": utility_code_name,
+                })
+            self.to_pyunicode_utility = (utility_code_name, to_pyunicode_utility)
+        else:
+            utility_code_name, to_pyunicode_utility = self.to_pyunicode_utility
+        code.globalstate.use_utility_code(to_pyunicode_utility)
+        return utility_code_name
 
     def declaration_code(self, entity_code,
             for_display = 0, dll_linkage = None, pyrex = 0):

Cython/Utility/TypeConversion.c

@@ -654,16 +654,10 @@ static CYTHON_INLINE PyObject* {{TO_PY_FUNCTION}}({{TYPE}} value, char format_ch
 }
 
 
-/////////////// NewOwnedRef.proto ///////////////
+/////////////// CBIntToPyUnicode.proto ///////////////
 
-static CYTHON_INLINE PyObject* __Pyx_NewOwnedRef(PyObject* value);
-
-/////////////// NewOwnedRef ///////////////
-
-static CYTHON_INLINE PyObject* __Pyx_NewOwnedRef(PyObject* value) {
-    Py_INCREF(value);
-    return value;
-}
+#define {{TO_PY_FUNCTION}}(value, format_char)  \
+    ((value) ? (Py_INCREF({{TRUE_CONST}}), {{TRUE_CONST}}) :  (Py_INCREF({{FALSE_CONST}}), {{FALSE_CONST}}))
 
 
 /////////////// PyIntFromDouble.proto ///////////////

tests/run/fstring.pyx

@@ -66,6 +66,41 @@ def format_c_numbers(signed char c, short s, int n, long l, float f, double d):
     return s1, s2, s3, s4
 
 
+def format_bool(bint x):
+    """
+    >>> a, b, c, d = format_bool(1)
+    >>> print(a)  # 1
+    True
+    >>> print(b)  # 1
+    True
+    >>> print(c)  # 1
+    False
+    >>> print(d)  # 1
+    False
+
+    >>> a, b, c, d = format_bool(2)
+    >>> print(a)  # 2
+    True
+    >>> print(b)  # 2
+    True
+    >>> print(c)  # 2
+    False
+    >>> print(d)  # 2
+    False
+
+    >>> a, b, c, d = format_bool(0)
+    >>> print(a)  # 3
+    False
+    >>> print(b)  # 3
+    True
+    >>> print(c)  # 3
+    False
+    >>> print(d)  # 3
+    False
+    """
+    return f'{x}', f'{True}', f'{x == 2}', f'{2 > 3}'
+
+
 def format_c_values(Py_UCS4 uchar, Py_UNICODE pyunicode):
     """
     >>> s, s1, s2 = format_c_values(b'A'.decode('ascii'), b'X'.decode('ascii'))