compilers: Tell mypy that the compiler mixins are just that

We do this by making the mixins inherit the Compiler class only when
mypy is examining the code (using some clever inheritance shenanigans).
This caught a bunch of issues, and also lets us delete a ton of code.

1 files changed, 8 insertions, 6 deletions

diff --git a/mesonbuild/compilers/mixins/pgi.py b/mesonbuild/compilers/mixins/pgi.py
index d69abda..f6ad279 100644
--- a/mesonbuild/compilers/mixins/pgi.py
+++ b/mesonbuild/compilers/mixins/pgi.py
@@ -21,8 +21,14 @@ from pathlib import Path
 from ..compilers import clike_debug_args, clike_optimization_args
 
 if T.TYPE_CHECKING:
-    from ...envconfig import MachineInfo
     from ...environment import Environment
+    from ...compilers.compilers import Compiler
+else:
+    # This is a bit clever, for mypy we pretend that these mixins descend from
+    # Compiler, so we get all of the methods and attributes defined for us, but
+    # for runtime we make them descend from object (which all classes normally
+    # do). This gives up DRYer type checking, with no runtime impact
+    Compiler = object
 
 pgi_buildtype_args = {
     'plain': [],
@@ -34,11 +40,7 @@ pgi_buildtype_args = {
 }  # type: T.Dict[str, T.List[str]]
 
 
-class PGICompiler:
-
-    if T.TYPE_CHECKING:
-        info = MachineInfo('', '', '', '')
-        language = ''
+class PGICompiler(Compiler):
 
     def __init__(self) -> None:
         self.base_options = ['b_pch']