correct spelling mistakes (#4042)

Author: EdwardBetts

docs/source/cheat_sheet_py3.rst

@@ -239,7 +239,7 @@ Other stuff
        else:
            return sys.stdout
 
-   # forward references are useful if you want to referemce a class before it is designed
+   # forward references are useful if you want to reference a class before it is designed
    
    def f(foo: A) -> int:  # this will fail
        ...
@@ -304,4 +304,4 @@ Mypy brings limited support for PEP 526 annotations.
         def __init__(self) -> None:
             self.items: List[str] = []
    
-Please see :ref:`python-36` for more on mypy's compatability with Python 3.6's new features.
+Please see :ref:`python-36` for more on mypy's compatibility with Python 3.6's new features.

docs/source/kinds_of_types.rst

@@ -977,7 +977,7 @@ a value, you should use the
 Note that unlike many other generics in the typing module, the ``SendType`` of
 ``Generator`` behaves contravariantly, not covariantly or invariantly.
 
-If you do not plan on recieving or returning values, then set the ``SendType``
+If you do not plan on receiving or returning values, then set the ``SendType``
 or ``ReturnType`` to ``None``, as appropriate. For example, we could have
 annotated the first example as the following:
 

misc/incremental_checker.py

@@ -9,7 +9,7 @@
 re-runs mypy on the commits with incremental mode enabled to make sure it returns
 the same results.
 
-This script will download and test the offical mypy repo by default. Running:
+This script will download and test the official mypy repo by default. Running:
 
     python3 misc/incremental_checker.py last 30
 

misc/upload-pypi.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python3
 """Build and upload mypy packages for Linux and macOS to PyPI.
 
-Note: This should be run on macOS using offical python.org Python 3.6 or
+Note: This should be run on macOS using official python.org Python 3.6 or
       later, as this is the only tested configuration. Use --force to
       run anyway.
 

mypy/checker.py

@@ -1146,7 +1146,7 @@ def check_override(self, override: FunctionLike, original: FunctionLike,
                 # variables. If an argument or return type of override
                 # does not have the correct subtyping relationship
                 # with the original type even after these variables
-                # are erased, then it is definitely an incompatiblity.
+                # are erased, then it is definitely an incompatibility.
 
                 override_ids = override.type_var_ids()
 

mypy/checkexpr.py

@@ -66,7 +66,7 @@ def extract_refexpr_names(expr: RefExpr) -> Set[str]:
     while expr.kind == MODULE_REF or expr.fullname is not None:
         if expr.kind == MODULE_REF and expr.fullname is not None:
             # If it's None, something's wrong (perhaps due to an
-            # import cycle or a supressed error).  For now we just
+            # import cycle or a suppressed error).  For now we just
             # skip it.
             output.add(expr.fullname)
 

mypy/semanal.py

@@ -156,7 +156,7 @@
 # nested functions. In the first phase we add the function to the symbol table
 # but don't process body. In the second phase we process function body. This
 # way we can have mutually recursive nested functions.
-FUNCTION_BOTH_PHASES = 0  # Everthing in one go
+FUNCTION_BOTH_PHASES = 0  # Everything in one go
 FUNCTION_FIRST_PHASE_POSTPONE_SECOND = 1  # Add to symbol table but postpone body
 FUNCTION_SECOND_PHASE = 2  # Only analyze body
 

mypy/test/testcheck.py

@@ -171,7 +171,7 @@ def run_case_once(self, testcase: DataDrivenTestCase, incremental_step: int = 0)
         if incremental_step:
             options.incremental = True
         else:
-            options.cache_dir = os.devnull  # Dont waste time writing cache
+            options.cache_dir = os.devnull  # Don't waste time writing cache
 
         sources = []
         for module_name, program_path, program_text in module_data: