mypyc: run pyupgrade (#12708)

Re-attempt of #10741
Ran: `pyupgrade --py36-plus $(fd -e py) --keep-runtime-typing`
I mostly only needed to change things where NamedTuple comments got
dropped.

mypyc/analysis/dataflow.py

@@ -125,7 +125,7 @@ def __init__(self, before: 'AnalysisDict[T]', after: 'AnalysisDict[T]') -> None:
         self.after = after
 
     def __str__(self) -> str:
-        return 'before: %s\nafter: %s\n' % (self.before, self.after)
+        return f'before: {self.before}\nafter: {self.after}\n'
 
 
 GenAndKill = Tuple[Set[Value], Set[Value]]

mypyc/analysis/ircheck.py

@@ -17,7 +17,7 @@
 from mypyc.ir.func_ir import FuncIR, FUNC_STATICMETHOD
 
 
-class FnError(object):
+class FnError:
     def __init__(self, source: Union[Op, BasicBlock], desc: str) -> None:
         self.source = source
         self.desc = desc
@@ -129,8 +129,7 @@ def check_op_sources_valid(fn: FuncIR) -> List[FnError]:
     return errors
 
 
-disjoint_types = set(
-    [
+disjoint_types = {
         int_rprimitive.name,
         bytes_rprimitive.name,
         str_rprimitive.name,
@@ -139,8 +138,7 @@ def check_op_sources_valid(fn: FuncIR) -> List[FnError]:
         set_rprimitive.name,
         tuple_rprimitive.name,
         range_rprimitive.name,
-    ]
-)
+}
 
 
 def can_coerce_to(src: RType, dest: RType) -> bool:

mypyc/build.py

@@ -200,7 +200,7 @@ def generate_c(sources: List[BuildSource],
 
     t1 = time.time()
     if compiler_options.verbose:
-        print("Parsed and typechecked in {:.3f}s".format(t1 - t0))
+        print(f"Parsed and typechecked in {t1 - t0:.3f}s")
 
     if not messages and result:
         errors = Errors()
@@ -212,7 +212,7 @@ def generate_c(sources: List[BuildSource],
 
     t2 = time.time()
     if compiler_options.verbose:
-        print("Compiled to C in {:.3f}s".format(t2 - t1))
+        print(f"Compiled to C in {t2 - t1:.3f}s")
 
     # ... you know, just in case.
     if options.junit_xml:
@@ -304,7 +304,7 @@ def write_file(path: str, contents: str) -> None:
     try:
         with open(path, 'rb') as f:
             old_contents: Optional[bytes] = f.read()
-    except IOError:
+    except OSError:
         old_contents = None
     if old_contents != encoded_contents:
         os.makedirs(os.path.dirname(path), exist_ok=True)
@@ -513,8 +513,8 @@ def mypycify(
     cflags: List[str] = []
     if compiler.compiler_type == 'unix':
         cflags += [
-            '-O{}'.format(opt_level),
-            '-g{}'.format(debug_level),
+            f'-O{opt_level}',
+            f'-g{debug_level}',
             '-Werror', '-Wno-unused-function', '-Wno-unused-label',
             '-Wno-unreachable-code', '-Wno-unused-variable',
             '-Wno-unused-command-line-argument', '-Wno-unknown-warning-option',
@@ -535,7 +535,7 @@ def mypycify(
         elif debug_level in ('2', '3'):
             debug_level = "FULL"
         cflags += [
-            '/O{}'.format(opt_level),
+            f'/O{opt_level}',
             f'/DEBUG:{debug_level}',
             '/wd4102',  # unreferenced label
             '/wd4101',  # unreferenced local variable

mypyc/codegen/cstring.py

@@ -23,7 +23,7 @@
 from typing_extensions import Final
 
 
-CHAR_MAP: Final = ["\\{:03o}".format(i) for i in range(256)]
+CHAR_MAP: Final = [f"\\{i:03o}" for i in range(256)]
 
 # It is safe to use string.printable as it always uses the C locale.
 for c in string.printable:
@@ -32,7 +32,7 @@
 # These assignments must come last because we prioritize simple escape
 # sequences over any other representation.
 for c in ('\'', '"', '\\', 'a', 'b', 'f', 'n', 'r', 't', 'v'):
-    escaped = '\\{}'.format(c)
+    escaped = f'\\{c}'
     decoded = escaped.encode('ascii').decode('unicode_escape')
     CHAR_MAP[ord(decoded)] = escaped