Potential fix for GH issue #3203

Gets the specialized type if possible from
NameNode.analyse_as_type

This does introduce a potential new bug:
```
cimport cython

just_float = cython.fused_type(float)

cdef OK1(just_float x):
    return just_float in floating

cdef fail1(just_float x, floating y):
    return just_float in floating

cdef fail2(floating x):
    return floating in floating

def show():
    """
    >>> show()
    True
    True
    True
    True
    """
    print(OK1(1.0))
    print(fail1(1.0, 2.0))
    print(fail1[float, double](1.0, 2.0))
    print(fail2[float](1.0))
```
fail1 and fail2 work before this patch but fail with it. It isn't
clear to me if this should actually be considered a bug. It
works in both versions with `cython.floating`, which possibly
suggests analyse_as_type in AttributeNode should also be changed

Cython/Compiler/ExprNodes.py

@@ -1961,6 +1961,12 @@ class NameNode(AtomicExprNode):
         if not entry:
             entry = env.lookup(self.name)
         if entry and entry.is_type:
+            if entry.type.is_fused and env.fused_to_specific:
+                try:
+                    return entry.type.specialize(env.fused_to_specific)
+                except KeyError:
+                    pass # lots of valid reasons why we may not be able to get a specific type
+                    # so don't fail
             return entry.type
         else:
             return None

tests/run/fused_cpp.pyx

@@ -2,6 +2,8 @@
 
 cimport cython
 from libcpp.vector cimport vector
+from libcpp.typeinfo cimport type_info
+from cython.operator cimport typeid
 
 def test_cpp_specialization(cython.floating element):
     """
@@ -14,3 +16,17 @@ def test_cpp_specialization(cython.floating element):
     cdef vector[cython.floating] *v = new vector[cython.floating]()
     v.push_back(element)
     print cython.typeof(v), cython.typeof(element), v.at(0)
+
+cdef fused C:
+   int
+   object
+
+cdef const type_info* tidint = &typeid(int)
+def typeid_call(C x):
+    """
+    For GH issue 3203
+    >>> typeid_call(1)
+    True
+    """
+    cdef const type_info* a = &typeid(C)
+    return a[0] == tidint[0]