Remove from_python_3 field from StrExpr (#13262)

mypy/exprtotype.py

@@ -169,11 +169,7 @@ def expr_to_unanalyzed_type(
  )
  elif isinstance(expr, StrExpr):
  return parse_type_string(
- expr.value,
- "builtins.str",
- expr.line,
- expr.column,
- assume_str_is_unicode=expr.from_python_3,
+ expr.value, "builtins.str", expr.line, expr.column, assume_str_is_unicode=True
  )
  elif isinstance(expr, BytesExpr):
  return parse_type_string(

mypy/literals.py

@@ -140,7 +140,7 @@ def visit_int_expr(self, e: IntExpr) -> Key:
  return ("Literal", e.value)
 
  def visit_str_expr(self, e: StrExpr) -> Key:
- return ("Literal", e.value, e.from_python_3)
+ return ("Literal", e.value)
 
  def visit_bytes_expr(self, e: BytesExpr) -> Key:
  return ("Literal", e.value)

mypy/nodes.py

@@ -1568,28 +1568,13 @@ def accept(self, visitor: ExpressionVisitor[T]) -> T:
 class StrExpr(Expression):
  """String literal"""
 
- __slots__ = ("value", "from_python_3")
+ __slots__ = ("value",)
 
  value: str # '' by default
 
- # Keeps track of whether this string originated from Python 2 source code vs
- # Python 3 source code. We need to keep track of this information so we can
- # correctly handle types that have "nested strings". For example, consider this
- # type alias, where we have a forward reference to a literal type:
- #
- # Alias = List["Literal['foo']"]
- #
- # When parsing this, we need to know whether the outer string and alias came from
- # Python 2 code vs Python 3 code so we can determine whether the inner `Literal['foo']`
- # is meant to be `Literal[u'foo']` or `Literal[b'foo']`.
- #
- # This field keeps track of that information.
- from_python_3: bool
-
- def __init__(self, value: str, from_python_3: bool = False) -> None:
+ def __init__(self, value: str) -> None:
  super().__init__()
  self.value = value
- self.from_python_3 = from_python_3
 
  def accept(self, visitor: ExpressionVisitor[T]) -> T:
  return visitor.visit_str_expr(self)

mypy/treetransform.py

@@ -386,7 +386,7 @@ def visit_int_expr(self, node: IntExpr) -> IntExpr:
  return IntExpr(node.value)
 
  def visit_str_expr(self, node: StrExpr) -> StrExpr:
- return StrExpr(node.value, node.from_python_3)
+ return StrExpr(node.value)
 
  def visit_bytes_expr(self, node: BytesExpr) -> BytesExpr:
  return BytesExpr(node.value)