Fix skeleton for csv.register_dialect in Py2 so 'dialect' parameter type is resolved and PyTypeCheckerInspectionTest is able to match args with params

python/helpers/python-skeletons/_csv.py

@@ -1,10 +1,13 @@
 """Skeleton for 'csv' stdlib module."""
 
-def register_dialect(name, dialect=None, **fmtparams=None):
+import _csv
+
+
+def register_dialect(name, dialect=None, **fmtparams):
     """Associate dialect with name.
 
     :type name: string
-    :type dialect: Dialect
+    :type dialect: _csv.Dialect
     :rtype: None
     """
     pass

python/testData/inspections/PyTypeCheckerInspection/CsvRegisterDialect/_csv.py

@@ -0,0 +1,5 @@
+def register_dialect(name, dialect):
+    pass
+
+class Dialect(object):
+    pass

python/testData/inspections/PyTypeCheckerInspection/CsvRegisterDialect/a.py

@@ -0,0 +1,6 @@
+import csv
+
+class A(object):
+    pass
+
+csv.register_dialect(<warning descr="Expected type 'Union[str, unicode]', got 'A' instead">A()</warning>, <warning descr="Expected type 'Dialect', got 'A' instead">A()</warning>, delimiter=':', quoting=csv.QUOTE_NONE)

python/testData/inspections/PyTypeCheckerInspection/CsvRegisterDialect/csv.py

@@ -0,0 +1,3 @@
+from _csv import register_dialect
+
+__all__ = ["register_dialect"]

python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java

@@ -326,4 +326,9 @@ public class PyTypeCheckerInspectionTest extends PyTestCase {
   public void testFunctionReturnType() {
     doTest();
   }
+
+  // PY-19522
+  public void testCsvRegisterDialect() {
+    doMultiFileTest();
+  }
 }