"""Generic node traverser visitor"""

from __future__ import annotations

from mypy_extensions import mypyc_attr, trait

from mypy.nodes import (

REVEAL_TYPE,

AssertStmt,

AssertTypeExpr,

AssignmentExpr,

AssignmentStmt,

AwaitExpr,

Block,

BreakStmt,

BytesExpr,

CallExpr,

CastExpr,

ClassDef,

ComparisonExpr,

ComplexExpr,

ConditionalExpr,

ContinueStmt,

Decorator,

DelStmt,

DictExpr,

DictionaryComprehension,

EllipsisExpr,

EnumCallExpr,

Expression,

ExpressionStmt,

FloatExpr,

ForStmt,

FuncBase,

FuncDef,

FuncItem,

GeneratorExpr,

GlobalDecl,

IfStmt,

Import,

ImportAll,

ImportFrom,

IndexExpr,

IntExpr,

LambdaExpr,

ListComprehension,

ListExpr,

MatchStmt,

MemberExpr,

MypyFile,

NamedTupleExpr,

NameExpr,

NewTypeExpr,

Node,

NonlocalDecl,

OperatorAssignmentStmt,

OpExpr,

OverloadedFuncDef,

ParamSpecExpr,

PassStmt,

RaiseStmt,

ReturnStmt,

RevealExpr,

SetComprehension,

SetExpr,

SliceExpr,

StarExpr,

StrExpr,

SuperExpr,

TryStmt,

TupleExpr,

TypeAlias,

TypeAliasExpr,

TypeApplication,

TypedDictExpr,

TypeVarExpr,

TypeVarTupleExpr,

UnaryExpr,

WhileStmt,

WithStmt,

YieldExpr,

YieldFromExpr,

)

from mypy.patterns import (

AsPattern,

ClassPattern,

MappingPattern,

OrPattern,

SequencePattern,

SingletonPattern,

StarredPattern,

ValuePattern,

)

from mypy.visitor import NodeVisitor

@trait

@mypyc_attr(allow_interpreted_subclasses=True)

class TraverserVisitor(NodeVisitor[None]):

"""A parse tree visitor that traverses the parse tree during visiting.

It does not perform any actions outside the traversal. Subclasses

should override visit methods to perform actions during

traversal. Calling the superclass method allows reusing the

traversal implementation.

"""

def __init__(self) -> None:

pass

# Visit methods

def visit_mypy_file(self, o: MypyFile) -> None:

for d in o.defs:

d.accept(self)

def visit_block(self, block: Block) -> None:

for s in block.body:

s.accept(self)

def visit_func(self, o: FuncItem) -> None:

if o.arguments is not None:

for arg in o.arguments:

init = arg.initializer

if init is not None:

init.accept(self)

for arg in o.arguments:

self.visit_var(arg.variable)

o.body.accept(self)

def visit_func_def(self, o: FuncDef) -> None:

self.visit_func(o)

def visit_overloaded_func_def(self, o: OverloadedFuncDef) -> None:

for item in o.items:

item.accept(self)

if o.impl:

o.impl.accept(self)

def visit_class_def(self, o: ClassDef) -> None:

for d in o.decorators:

d.accept(self)

for base in o.base_type_exprs:

base.accept(self)

if o.metaclass:

o.metaclass.accept(self)

for v in o.keywords.values():

v.accept(self)

o.defs.accept(self)

if o.analyzed:

o.analyzed.accept(self)

def visit_decorator(self, o: Decorator) -> None:

o.func.accept(self)

o.var.accept(self)

for decorator in o.decorators:

decorator.accept(self)

def visit_expression_stmt(self, o: ExpressionStmt) -> None:

o.expr.accept(self)

def visit_assignment_stmt(self, o: AssignmentStmt) -> None:

o.rvalue.accept(self)

for l in o.lvalues:

l.accept(self)

def visit_operator_assignment_stmt(self, o: OperatorAssignmentStmt) -> None:

o.rvalue.accept(self)

o.lvalue.accept(self)

def visit_while_stmt(self, o: WhileStmt) -> None:

o.expr.accept(self)

o.body.accept(self)

if o.else_body:

o.else_body.accept(self)

def visit_for_stmt(self, o: ForStmt) -> None:

o.index.accept(self)

o.expr.accept(self)

o.body.accept(self)

if o.else_body:

o.else_body.accept(self)

def visit_return_stmt(self, o: ReturnStmt) -> None:

if o.expr is not None:

o.expr.accept(self)

def visit_assert_stmt(self, o: AssertStmt) -> None:

if o.expr is not None:

o.expr.accept(self)

if o.msg is not None:

o.msg.accept(self)

def visit_del_stmt(self, o: DelStmt) -> None:

if o.expr is not None:

o.expr.accept(self)

def visit_if_stmt(self, o: IfStmt) -> None:

for e in o.expr:

e.accept(self)

for b in o.body:

b.accept(self)

if o.else_body:

o.else_body.accept(self)

def visit_raise_stmt(self, o: RaiseStmt) -> None:

if o.expr is not None:

o.expr.accept(self)

if o.from_expr is not None:

o.from_expr.accept(self)

def visit_try_stmt(self, o: TryStmt) -> None:

o.body.accept(self)

for i in range(len(o.types)):

tp = o.types[i]

if tp is not None:

tp.accept(self)

o.handlers[i].accept(self)

for v in o.vars:

if v is not None:

v.accept(self)

if o.else_body is not None:

o.else_body.accept(self)

if o.finally_body is not None:

o.finally_body.accept(self)

def visit_with_stmt(self, o: WithStmt) -> None:

for i in range(len(o.expr)):

o.expr[i].accept(self)

targ = o.target[i]

if targ is not None:

targ.accept(self)

o.body.accept(self)

def visit_match_stmt(self, o: MatchStmt) -> None:

o.subject.accept(self)

for i in range(len(o.patterns)):

o.patterns[i].accept(self)

guard = o.guards[i]

if guard is not None:

guard.accept(self)

o.bodies[i].accept(self)

def visit_member_expr(self, o: MemberExpr) -> None:

o.expr.accept(self)

def visit_yield_from_expr(self, o: YieldFromExpr) -> None:

o.expr.accept(self)

def visit_yield_expr(self, o: YieldExpr) -> None:

if o.expr:

o.expr.accept(self)

def visit_call_expr(self, o: CallExpr) -> None:

o.callee.accept(self)

for a in o.args:

a.accept(self)

if o.analyzed:

o.analyzed.accept(self)

def visit_op_expr(self, o: OpExpr) -> None:

o.left.accept(self)

o.right.accept(self)

if o.analyzed is not None:

o.analyzed.accept(self)

def visit_comparison_expr(self, o: ComparisonExpr) -> None:

for operand in o.operands:

operand.accept(self)

def visit_slice_expr(self, o: SliceExpr) -> None:

if o.begin_index is not None:

o.begin_index.accept(self)

if o.end_index is not None:

o.end_index.accept(self)

if o.stride is not None:

o.stride.accept(self)

def visit_cast_expr(self, o: CastExpr) -> None:

o.expr.accept(self)

def visit_assert_type_expr(self, o: AssertTypeExpr) -> None:

o.expr.accept(self)

def visit_reveal_expr(self, o: RevealExpr) -> None:

if o.kind == REVEAL_TYPE:

assert o.expr is not None

o.expr.accept(self)

else:

# RevealLocalsExpr doesn't have an inner expression

pass

def visit_assignment_expr(self, o: AssignmentExpr) -> None:

o.target.accept(self)

o.value.accept(self)

def visit_unary_expr(self, o: UnaryExpr) -> None:

o.expr.accept(self)

def visit_list_expr(self, o: ListExpr) -> None:

for item in o.items:

item.accept(self)

def visit_tuple_expr(self, o: TupleExpr) -> None:

for item in o.items:

item.accept(self)

def visit_dict_expr(self, o: DictExpr) -> None:

for k, v in o.items:

if k is not None:

k.accept(self)

v.accept(self)

def visit_set_expr(self, o: SetExpr) -> None:

for item in o.items:

item.accept(self)

def visit_index_expr(self, o: IndexExpr) -> None:

o.base.accept(self)

o.index.accept(self)

if o.analyzed:

o.analyzed.accept(self)

def visit_generator_expr(self, o: GeneratorExpr) -> None:

for index, sequence, conditions in zip(o.indices, o.sequences, o.condlists):

sequence.accept(self)

index.accept(self)

for cond in conditions:

cond.accept(self)

o.left_expr.accept(self)

def visit_dictionary_comprehension(self, o: DictionaryComprehension) -> None:

for index, sequence, conditions in zip(o.indices, o.sequences, o.condlists):

sequence.accept(self)

index.accept(self)

for cond in conditions:

cond.accept(self)

o.key.accept(self)

o.value.accept(self)

def visit_list_comprehension(self, o: ListComprehension) -> None:

o.generator.accept(self)

def visit_set_comprehension(self, o: SetComprehension) -> None:

o.generator.accept(self)

def visit_conditional_expr(self, o: ConditionalExpr) -> None:

o.cond.accept(self)

o.if_expr.accept(self)

o.else_expr.accept(self)

def visit_type_application(self, o: TypeApplication) -> None:

o.expr.accept(self)

def visit_lambda_expr(self, o: LambdaExpr) -> None:

self.visit_func(o)

def visit_star_expr(self, o: StarExpr) -> None:

o.expr.accept(self)

def visit_await_expr(self, o: AwaitExpr) -> None:

o.expr.accept(self)

def visit_super_expr(self, o: SuperExpr) -> None:

o.call.accept(self)

def visit_as_pattern(self, o: AsPattern) -> None:

if o.pattern is not None:

o.pattern.accept(self)

if o.name is not None:

o.name.accept(self)

def visit_or_pattern(self, o: OrPattern) -> None:

for p in o.patterns:

p.accept(self)

def visit_value_pattern(self, o: ValuePattern) -> None:

o.expr.accept(self)

def visit_sequence_pattern(self, o: SequencePattern) -> None:

for p in o.patterns:

p.accept(self)

def visit_starred_pattern(self, o: StarredPattern) -> None:

if o.capture is not None:

o.capture.accept(self)

def visit_mapping_pattern(self, o: MappingPattern) -> None:

for key in o.keys:

key.accept(self)

for value in o.values:

value.accept(self)

if o.rest is not None:

o.rest.accept(self)

def visit_class_pattern(self, o: ClassPattern) -> None:

o.class_ref.accept(self)

for p in o.positionals:

p.accept(self)

for v in o.keyword_values:

v.accept(self)

def visit_import(self, o: Import) -> None:

for a in o.assignments:

a.accept(self)

def visit_import_from(self, o: ImportFrom) -> None:

for a in o.assignments:

a.accept(self)

class ExtendedTraverserVisitor(TraverserVisitor):

"""This is a more flexible traverser.

In addition to the base traverser it:

* has visit_ methods for leaf nodes

* has common method that is called for all nodes

* allows to skip recursing into a node

Note that this traverser still doesn't visit some internal

mypy constructs like _promote expression and Var.

"""

def visit(self, o: Node) -> bool:

# If returns True, will continue to nested nodes.

return True

def visit_mypy_file(self, o: MypyFile) -> None:

if not self.visit(o):

return

super().visit_mypy_file(o)

# Module structure

def visit_import(self, o: Import) -> None:

if not self.visit(o):

return

super().visit_import(o)

def visit_import_from(self, o: ImportFrom) -> None:

if not self.visit(o):

return

super().visit_import_from(o)

def visit_import_all(self, o: ImportAll) -> None:

if not self.visit(o):

return

super().visit_import_all(o)

# Definitions

def visit_func_def(self, o: FuncDef) -> None:

if not self.visit(o):

return

super().visit_func_def(o)

def visit_overloaded_func_def(self, o: OverloadedFuncDef) -> None:

if not self.visit(o):

return

super().visit_overloaded_func_def(o)

def visit_class_def(self, o: ClassDef) -> None:

if not self.visit(o):

return

super().visit_class_def(o)

def visit_global_decl(self, o: GlobalDecl) -> None:

if not self.visit(o):

return

super().visit_global_decl(o)

def visit_nonlocal_decl(self, o: NonlocalDecl) -> None:

if not self.visit(o):

return

super().visit_nonlocal_decl(o)

def visit_decorator(self, o: Decorator) -> None:

if not self.visit(o):

return

super().visit_decorator(o)

def visit_type_alias(self, o: TypeAlias) -> None:

if not self.visit(o):

return

super().visit_type_alias(o)

# Statements

def visit_block(self, block: Block) -> None:

if not self.visit(block):

return

super().visit_block(block)

def visit_expression_stmt(self, o: ExpressionStmt) -> None:

if not self.visit(o):

return

super().visit_expression_stmt(o)

def visit_assignment_stmt(self, o: AssignmentStmt) -> None:

if not self.visit(o):

return

super().visit_assignment_stmt(o)

def visit_operator_assignment_stmt(self, o: OperatorAssignmentStmt) -> None:

if not self.visit(o):

return

super().visit_operator_assignment_stmt(o)

def visit_while_stmt(self, o: WhileStmt) -> None:

if not self.visit(o):

return

super().visit_while_stmt(o)

def visit_for_stmt(self, o: ForStmt) -> None:

if not self.visit(o):

return

super().visit_for_stmt(o)

def visit_return_stmt(self, o: ReturnStmt) -> None:

if not self.visit(o):

return

super().visit_return_stmt(o)

def visit_assert_stmt(self, o: AssertStmt) -> None:

if not self.visit(o):

return

super().visit_assert_stmt(o)

def visit_del_stmt(self, o: DelStmt) -> None:

if not self.visit(o):

return

super().visit_del_stmt(o)

def visit_if_stmt(self, o: IfStmt) -> None:

if not self.visit(o):

return

super().visit_if_stmt(o)

def visit_break_stmt(self, o: BreakStmt) -> None:

if not self.visit(o):

return

super().visit_break_stmt(o)

def visit_continue_stmt(self, o: ContinueStmt) -> None:

if not self.visit(o):

return

super().visit_continue_stmt(o)

def visit_pass_stmt(self, o: PassStmt) -> None:

if not self.visit(o):

return

super().visit_pass_stmt(o)

def visit_raise_stmt(self, o: RaiseStmt) -> None:

if not self.visit(o):

return

super().visit_raise_stmt(o)

def visit_try_stmt(self, o: TryStmt) -> None:

if not self.visit(o):

return

super().visit_try_stmt(o)

def visit_with_stmt(self, o: WithStmt) -> None:

if not self.visit(o):

return

super().visit_with_stmt(o)

def visit_match_stmt(self, o: MatchStmt) -> None:

if not self.visit(o):

return

super().visit_match_stmt(o)

# Expressions (default no-op implementation)

def visit_int_expr(self, o: IntExpr) -> None:

if not self.visit(o):

return

super().visit_int_expr(o)

def visit_str_expr(self, o: StrExpr) -> None:

if not self.visit(o):

return

super().visit_str_expr(o)

def visit_bytes_expr(self, o: BytesExpr) -> None:

if not self.visit(o):

return

super().visit_bytes_expr(o)

def visit_float_expr(self, o: FloatExpr) -> None:

if not self.visit(o):

return

super().visit_float_expr(o)

def visit_complex_expr(self, o: ComplexExpr) -> None:

if not self.visit(o):

return

super().visit_complex_expr(o)

def visit_ellipsis(self, o: EllipsisExpr) -> None:

if not self.visit(o):

return

super().visit_ellipsis(o)

def visit_star_expr(self, o: StarExpr) -> None:

if not self.visit(o):

return

super().visit_star_expr(o)

def visit_name_expr(self, o: NameExpr) -> None:

if not self.visit(o):

return

super().visit_name_expr(o)

def visit_member_expr(self, o: MemberExpr) -> None:

if not self.visit(o):

return

super().visit_member_expr(o)

def visit_yield_from_expr(self, o: YieldFromExpr) -> None:

if not self.visit(o):

return

super().visit_yield_from_expr(o)

def visit_yield_expr(self, o: YieldExpr) -> None:

if not self.visit(o):

return

super().visit_yield_expr(o)

def visit_call_expr(self, o: CallExpr) -> None:

if not self.visit(o):

return

super().visit_call_expr(o)

def visit_op_expr(self, o: OpExpr) -> None:

if not self.visit(o):

return

super().visit_op_expr(o)

def visit_comparison_expr(self, o: ComparisonExpr) -> None:

if not self.visit(o):

return

super().visit_comparison_expr(o)

def visit_cast_expr(self, o: CastExpr) -> None:

if not self.visit(o):

return

super().visit_cast_expr(o)

def visit_assert_type_expr(self, o: AssertTypeExpr) -> None:

if not self.visit(o):

return

super().visit_assert_type_expr(o)

def visit_reveal_expr(self, o: RevealExpr) -> None:

if not self.visit(o):

return

super().visit_reveal_expr(o)

def visit_super_expr(self, o: SuperExpr) -> None:

if not self.visit(o):

return

super().visit_super_expr(o)

def visit_assignment_expr(self, o: AssignmentExpr) -> None:

if not self.visit(o):

return

super().visit_assignment_expr(o)

def visit_unary_expr(self, o: UnaryExpr) -> None:

if not self.visit(o):

return

super().visit_unary_expr(o)

def visit_list_expr(self, o: ListExpr) -> None:

if not self.visit(o):

return

super().visit_list_expr(o)

def visit_dict_expr(self, o: DictExpr) -> None:

if not self.visit(o):

return

super().visit_dict_expr(o)

def visit_tuple_expr(self, o: TupleExpr) -> None:

if not self.visit(o):

return

super().visit_tuple_expr(o)

def visit_set_expr(self, o: SetExpr) -> None:

if not self.visit(o):

return

super().visit_set_expr(o)

def visit_index_expr(self, o: IndexExpr) -> None:

if not self.visit(o):

return

super().visit_index_expr(o)

def visit_type_application(self, o: TypeApplication) -> None:

if not self.visit(o):

return

super().visit_type_application(o)

def visit_lambda_expr(self, o: LambdaExpr) -> None:

if not self.visit(o):

return

super().visit_lambda_expr(o)

def visit_list_comprehension(self, o: ListComprehension) -> None:

if not self.visit(o):

return

super().visit_list_comprehension(o)

def visit_set_comprehension(self, o: SetComprehension) -> None:

if not self.visit(o):

return

super().visit_set_comprehension(o)

def visit_dictionary_comprehension(self, o: DictionaryComprehension) -> None:

if not self.visit(o):

return

super().visit_dictionary_comprehension(o)

def visit_generator_expr(self, o: GeneratorExpr) -> None:

if not self.visit(o):

return

super().visit_generator_expr(o)

def visit_slice_expr(self, o: SliceExpr) -> None:

if not self.visit(o):

return

super().visit_slice_expr(o)

def visit_conditional_expr(self, o: ConditionalExpr) -> None:

if not self.visit(o):

return

super().visit_conditional_expr(o)

def visit_type_var_expr(self, o: TypeVarExpr) -> None:

if not self.visit(o):

return

super().visit_type_var_expr(o)

def visit_paramspec_expr(self, o: ParamSpecExpr) -> None:

if not self.visit(o):

return

super().visit_paramspec_expr(o)

def visit_type_var_tuple_expr(self, o: TypeVarTupleExpr) -> None:

if not self.visit(o):

return

super().visit_type_var_tuple_expr(o)

def visit_type_alias_expr(self, o: TypeAliasExpr) -> None:

if not self.visit(o):

return

super().visit_type_alias_expr(o)

def visit_namedtuple_expr(self, o: NamedTupleExpr) -> None:

if not self.visit(o):

return

super().visit_namedtuple_expr(o)

def visit_enum_call_expr(self, o: EnumCallExpr) -> None:

if not self.visit(o):

return

super().visit_enum_call_expr(o)

def visit_typeddict_expr(self, o: TypedDictExpr) -> None:

if not self.visit(o):

return

super().visit_typeddict_expr(o)

def visit_newtype_expr(self, o: NewTypeExpr) -> None:

if not self.visit(o):

return

super().visit_newtype_expr(o)

def visit_await_expr(self, o: AwaitExpr) -> None:

if not self.visit(o):

return

super().visit_await_expr(o)

# Patterns

def visit_as_pattern(self, o: AsPattern) -> None:

if not self.visit(o):

return

super().visit_as_pattern(o)

def visit_or_pattern(self, o: OrPattern) -> None:

if not self.visit(o):

return

super().visit_or_pattern(o)

def visit_value_pattern(self, o: ValuePattern) -> None:

if not self.visit(o):

return

super().visit_value_pattern(o)

def visit_singleton_pattern(self, o: SingletonPattern) -> None:

if not self.visit(o):

return

super().visit_singleton_pattern(o)

def visit_sequence_pattern(self, o: SequencePattern) -> None:

if not self.visit(o):

return

super().visit_sequence_pattern(o)

def visit_starred_pattern(self, o: StarredPattern) -> None:

if not self.visit(o):

return

super().visit_starred_pattern(o)

def visit_mapping_pattern(self, o: MappingPattern) -> None:

if not self.visit(o):

return

super().visit_mapping_pattern(o)

def visit_class_pattern(self, o: ClassPattern) -> None:

if not self.visit(o):

return

super().visit_class_pattern(o)

class ReturnSeeker(TraverserVisitor):

def __init__(self) -> None:

self.found = False

def visit_return_stmt(self, o: ReturnStmt) -> None:

if o.expr is None or isinstance(o.expr, NameExpr) and o.expr.name == "None":

return

self.found = True

def has_return_statement(fdef: FuncBase) -> bool:

"""Find if a function has a non-trivial return statement.

Plain 'return' and 'return None' don't count.

"""

seeker = ReturnSeeker()

fdef.accept(seeker)

return seeker.found

class FuncCollectorBase(TraverserVisitor):

def __init__(self) -> None:

self.inside_func = False

def visit_func_def(self, defn: FuncDef) -> None:

if not self.inside_func:

self.inside_func = True

super().visit_func_def(defn)

self.inside_func = False

class YieldSeeker(FuncCollectorBase):

def __init__(self) -> None:

super().__init__()

self.found = False

def visit_yield_expr(self, o: YieldExpr) -> None:

self.found = True

def has_yield_expression(fdef: FuncBase) -> bool:

seeker = YieldSeeker()

fdef.accept(seeker)

return seeker.found

class YieldFromSeeker(FuncCollectorBase):

def __init__(self) -> None:

super().__init__()

self.found = False

def visit_yield_from_expr(self, o: YieldFromExpr) -> None:

self.found = True

def has_yield_from_expression(fdef: FuncBase) -> bool:

seeker = YieldFromSeeker()

fdef.accept(seeker)

return seeker.found

class AwaitSeeker(TraverserVisitor):

def __init__(self) -> None:

super().__init__()

self.found = False

def visit_await_expr(self, o: AwaitExpr) -> None:

self.found = True

def has_await_expression(expr: Expression) -> bool:

seeker = AwaitSeeker()

expr.accept(seeker)

return seeker.found

class ReturnCollector(FuncCollectorBase):

def __init__(self) -> None:

super().__init__()

self.return_statements: list[ReturnStmt] = []

def visit_return_stmt(self, stmt: ReturnStmt) -> None:

self.return_statements.append(stmt)

def all_return_statements(node: Node) -> list[ReturnStmt]:

v = ReturnCollector()

node.accept(v)

return v.return_statements

class YieldCollector(FuncCollectorBase):

def __init__(self) -> None:

super().__init__()

self.in_assignment = False

self.yield_expressions: list[tuple[YieldExpr, bool]] = []

def visit_assignment_stmt(self, stmt: AssignmentStmt) -> None:

self.in_assignment = True

super().visit_assignment_stmt(stmt)

self.in_assignment = False

def visit_yield_expr(self, expr: YieldExpr) -> None:

self.yield_expressions.append((expr, self.in_assignment))

def all_yield_expressions(node: Node) -> list[tuple[YieldExpr, bool]]:

v = YieldCollector()

node.accept(v)

return v.yield_expressions

class YieldFromCollector(FuncCollectorBase):

def __init__(self) -> None:

super().__init__()

self.in_assignment = False

self.yield_from_expressions: list[tuple[YieldFromExpr, bool]] = []

def visit_assignment_stmt(self, stmt: AssignmentStmt) -> None:

self.in_assignment = True

super().visit_assignment_stmt(stmt)

self.in_assignment = False

def visit_yield_from_expr(self, expr: YieldFromExpr) -> None:

self.yield_from_expressions.append((expr, self.in_assignment))

def all_yield_from_expressions(node: Node) -> list[tuple[YieldFromExpr, bool]]:

v = YieldFromCollector()

node.accept(v)

return v.yield_from_expressions