currently it does only basic behavior and works only for module known to path resolver and loaded modules (variable module)

no test yet. require many refactorings

…-server into addimport

… diagnostic cached for latest analysis

the reason it was assert was due to code like below that defines 2 functions with same signature and we only keep 1 symbol out of it.
...
       def f(x):
            class C:
                x = 12
                def m(self):
                    return x
                locals()
            return C

        self.assertEqual(f(1).x, 12)

        def f(x):
            class C:
                y = x
                def m(self):
                    return x
                z = list(locals())
            return C
...

added just one since it is very expensive.

…lready loaded by users code.

for closed files that are never loaded in the editor before, it will use SymbolIndexer to find candidates.

but since the indexer is syntax based, it wont be able to provide information that require semantic info such as imported members

ex) from os import * or __all__.extend(core.__all__)

which means we will not propose

from os.path import join

if os module is not already loaded, instead we will propose ntpath or mac/posixpath since that is where join is actually defined.

unfortunately we can't load modules just for add import, it is too expensive.

we might in future add another index that is based on analyzed data which could have correct info saved. but for now, this is what we decided.

…t numpy

…or abbreviation

now we show them at the top if there is any.

…-server into addimport