Fixes for mypy 0.600 (#324)

* Remove the mypy version constraint and set strict_optional to False.

* Add type annotations for `ISA` variables.

mypy 0.600 seems to require explicit annotations here.

* Annotate the ISA variables in the defs.py files too.

lib/codegen/meta/isa/arm32/__init__.py

@@ -9,6 +9,7 @@ This target ISA generates code for ARMv7 and ARMv8 CPUs in 32-bit mode
 from __future__ import absolute_import
 from . import defs
 from . import settings, registers  # noqa
+from cdsl.isa import TargetISA  # noqa
 
 # Re-export the primary target ISA definition.
-ISA = defs.ISA.finish()
+ISA = defs.ISA.finish()  # type: TargetISA

lib/codegen/meta/isa/arm32/defs.py

@@ -8,7 +8,7 @@ from cdsl.isa import TargetISA, CPUMode
 import base.instructions
 from base.legalize import narrow
 
-ISA = TargetISA('arm32', [base.instructions.GROUP])
+ISA = TargetISA('arm32', [base.instructions.GROUP])  # type: TargetISA
 
 # CPU modes for 32-bit ARM and Thumb2.
 A32 = CPUMode('A32', ISA)

lib/codegen/meta/isa/arm64/__init__.py

@@ -8,6 +8,7 @@ ARMv8 CPUs running the Aarch64 architecture.
 from __future__ import absolute_import
 from . import defs
 from . import settings, registers  # noqa
+from cdsl.isa import TargetISA  # noqa
 
 # Re-export the primary target ISA definition.
-ISA = defs.ISA.finish()
+ISA = defs.ISA.finish()  # type: TargetISA

lib/codegen/meta/isa/arm64/defs.py

@@ -8,7 +8,7 @@ from cdsl.isa import TargetISA, CPUMode
 import base.instructions
 from base.legalize import narrow
 
-ISA = TargetISA('arm64', [base.instructions.GROUP])
+ISA = TargetISA('arm64', [base.instructions.GROUP])  # type: TargetISA
 A64 = CPUMode('A64', ISA)
 
 # TODO: Refine these

lib/codegen/meta/isa/riscv/__init__.py

@@ -27,6 +27,7 @@ RV32G / RV64G
 from __future__ import absolute_import
 from . import defs
 from . import encodings, settings, registers  # noqa
+from cdsl.isa import TargetISA  # noqa
 
 # Re-export the primary target ISA definition.
-ISA = defs.ISA.finish()
+ISA = defs.ISA.finish()  # type: TargetISA

lib/codegen/meta/isa/riscv/defs.py

@@ -7,7 +7,7 @@ from __future__ import absolute_import
 from cdsl.isa import TargetISA, CPUMode
 import base.instructions
 
-ISA = TargetISA('riscv', [base.instructions.GROUP])
+ISA = TargetISA('riscv', [base.instructions.GROUP])  # type: TargetISA
 
 # CPU modes for 32-bit and 64-bit operation.
 RV32 = CPUMode('RV32', ISA)

lib/codegen/meta/isa/x86/__init__.py

@@ -16,6 +16,7 @@ This target ISA generates code for x86 CPUs with two separate CPU modes:
 from __future__ import absolute_import
 from . import defs
 from . import encodings, settings, registers  # noqa
+from cdsl.isa import TargetISA  # noqa
 
 # Re-export the primary target ISA definition.
-ISA = defs.ISA.finish()
+ISA = defs.ISA.finish()  # type: TargetISA

lib/codegen/meta/isa/x86/defs.py

@@ -9,7 +9,7 @@ import base.instructions
 from . import instructions as x86
 from base.immediates import floatcc
 
-ISA = TargetISA('x86', [base.instructions.GROUP, x86.GROUP])
+ISA = TargetISA('x86', [base.instructions.GROUP, x86.GROUP])  # type: TargetISA
 
 # CPU modes for 32-bit and 64-bit operation.
 X86_64 = CPUMode('I64', ISA)

lib/codegen/meta/mypy.ini

@@ -2,3 +2,4 @@
 disallow_untyped_defs = True
 warn_unused_ignores = True
 warn_return_any = True
+strict_optional = False