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Copy pathmodel.rs
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3043 lines (2748 loc) · 116 KB
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use std::path::Path;
use bitflags::bitflags;
use rustc_hash::FxHashMap;
use ruff_python_ast::helpers::{from_relative_import, map_subscript};
use ruff_python_ast::name::{QualifiedName, UnqualifiedName};
use ruff_python_ast::{self as ast, Expr, ExprContext, PySourceType, PythonVersion, Stmt};
use ruff_python_stdlib::builtins::{is_python_builtin, python_builtins, python_magic_globals};
use ruff_text_size::{Ranged, TextRange, TextSize};
use crate::Imported;
use crate::analyze::visibility;
use crate::binding::{
Binding, BindingFlags, BindingId, BindingKind, Bindings, Exceptions, FromImport, Import,
SubmoduleImport,
};
use crate::branches::{BranchId, Branches};
use crate::context::ExecutionContext;
use crate::definition::{Definition, DefinitionId, Definitions, Member, Module};
use crate::globals::{Globals, GlobalsArena};
use crate::nodes::{NodeId, NodeRef, Nodes};
use crate::reference::{
ResolvedReference, ResolvedReferenceId, ResolvedReferences, UnresolvedReference,
UnresolvedReferenceFlags, UnresolvedReferences,
};
use crate::scope::{Scope, ScopeId, ScopeKind, Scopes};
pub mod all;
/// The result of looking up a symbol in a [`SemanticModel`].
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub enum Symbol {
/// The symbol resolves to a concrete binding.
Binding(BindingId),
/// The symbol resolves to a builtin that has not been materialized yet.
Builtin,
/// The symbol does not resolve to any binding.
Unbound,
}
impl Symbol {
/// Returns the [`BindingId`] if this symbol resolves to a concrete binding.
pub const fn binding_id(self) -> Option<BindingId> {
match self {
Self::Binding(binding_id) => Some(binding_id),
Self::Builtin | Self::Unbound => None,
}
}
/// Returns `true` if this symbol resolves to any binding, including a builtin.
pub const fn is_bound(self) -> bool {
!matches!(self, Self::Unbound)
}
}
/// A semantic model for a Python module, to enable querying the module's semantic information.
pub struct SemanticModel<'a> {
typing_modules: &'a [String],
custom_builtins: &'a [String],
target_version: PythonVersion,
source_type: PySourceType,
module: Module<'a>,
/// Stack of all AST nodes in the program.
nodes: Nodes<'a>,
/// The ID of the current AST node.
node_id: Option<NodeId>,
/// Stack of all branches in the program.
branches: Branches,
/// The ID of the current branch.
branch_id: Option<BranchId>,
/// Stack of all scopes, along with the identifier of the current scope.
pub scopes: Scopes<'a>,
pub scope_id: ScopeId,
/// Stack of all definitions created in any scope, at any point in execution.
pub definitions: Definitions<'a>,
/// The ID of the current definition.
pub definition_id: DefinitionId,
/// A stack of all bindings created in any scope, at any point in execution.
pub bindings: Bindings<'a>,
/// Stack of all references created in any scope, at any point in execution.
resolved_references: ResolvedReferences,
/// Stack of all unresolved references created in any scope, at any point in execution.
unresolved_references: UnresolvedReferences,
/// Arena of global bindings.
globals: GlobalsArena<'a>,
/// Map from binding ID to binding ID that it shadows (in another scope).
///
/// For example, given:
/// ```python
/// import x
///
/// def f():
/// x = 1
/// ```
///
/// In this case, the binding created by `x = 1` shadows the binding created by `import x`,
/// despite the fact that they're in different scopes.
pub shadowed_bindings: FxHashMap<BindingId, BindingId>,
/// Map from binding index to indexes of bindings that annotate it (in the same scope).
///
/// For example, given:
/// ```python
/// x = 1
/// x: int
/// ```
///
/// In this case, the binding created by `x = 1` is annotated by the binding created by
/// `x: int`. We don't consider the latter binding to _shadow_ the former, because it doesn't
/// change the value of the binding, and so we don't store in on the scope. But we _do_ want to
/// track the annotation in some form, since it's a reference to `x`.
///
/// Note that, given:
/// ```python
/// x: int
/// ```
///
/// In this case, we _do_ store the binding created by `x: int` directly on the scope, and not
/// as a delayed annotation. Annotations are thus treated as bindings only when they are the
/// first binding in a scope; any annotations that follow are treated as "delayed" annotations.
delayed_annotations: FxHashMap<BindingId, Vec<BindingId>>,
/// Map from binding ID to the IDs of all scopes in which it is declared a `global` or
/// `nonlocal`.
///
/// For example, given:
/// ```python
/// x = 1
///
/// def f():
/// global x
/// ```
///
/// In this case, the binding created by `x = 1` is rebound within the scope created by `f`
/// by way of the `global x` statement.
rebinding_scopes: FxHashMap<BindingId, Vec<ScopeId>>,
/// Flags for the semantic model.
pub flags: SemanticModelFlags,
/// Modules that have been seen by the semantic model.
pub seen: Modules,
/// Exceptions that are handled by the current `try` block.
///
/// For example, if we're visiting the `x = 1` assignment below,
/// `AttributeError` is considered to be a "handled exception",
/// but `TypeError` is not:
///
/// ```py
/// try:
/// try:
/// foo()
/// except TypeError:
/// pass
/// except AttributeError:
/// pass
/// ```
pub handled_exceptions: Vec<Exceptions>,
/// Map from [`ast::ExprName`] node (represented as a [`NameId`]) to the [`Binding`] to which
/// it resolved (represented as a [`BindingId`]).
resolved_names: FxHashMap<NameId, BindingId>,
}
impl<'a> SemanticModel<'a> {
pub fn new(
typing_modules: &'a [String],
custom_builtins: &'a [String],
target_version: PythonVersion,
source_type: PySourceType,
path: &Path,
module: Module<'a>,
) -> Self {
let mut semantic = Self {
typing_modules,
custom_builtins,
target_version,
source_type,
module,
nodes: Nodes::default(),
node_id: None,
branches: Branches::default(),
branch_id: None,
scopes: Scopes::default(),
scope_id: ScopeId::global(),
definitions: Definitions::for_module(module),
definition_id: DefinitionId::module(),
bindings: Bindings::default(),
resolved_references: ResolvedReferences::default(),
unresolved_references: UnresolvedReferences::default(),
globals: GlobalsArena::default(),
shadowed_bindings: FxHashMap::default(),
delayed_annotations: FxHashMap::default(),
rebinding_scopes: FxHashMap::default(),
flags: SemanticModelFlags::new(path),
seen: Modules::empty(),
handled_exceptions: Vec::default(),
resolved_names: FxHashMap::default(),
};
let builtin_count = python_builtins(target_version.minor, source_type.is_ipynb()).count()
+ python_magic_globals(target_version.minor).count()
+ custom_builtins.len();
// Match the capacity that repeated `push` calls would reach while avoiding the
// intermediate allocations.
semantic
.bindings
.reserve_exact(builtin_count.next_power_of_two());
semantic.global_scope_mut().reserve_bindings(builtin_count);
semantic
}
/// Return the [`Binding`] for the given [`BindingId`].
#[inline]
pub fn binding(&self, id: BindingId) -> &Binding<'a> {
&self.bindings[id]
}
/// Resolve the [`ResolvedReference`] for the given [`ResolvedReferenceId`].
#[inline]
pub fn reference(&self, id: ResolvedReferenceId) -> &ResolvedReference {
&self.resolved_references[id]
}
/// Return `true` if the `Expr` is a reference to `typing.${target}`.
pub fn match_typing_expr(&self, expr: &Expr, target: &str) -> bool {
self.seen_typing()
&& self
.resolve_qualified_name(expr)
.is_some_and(|qualified_name| {
self.match_typing_qualified_name(&qualified_name, target)
})
}
/// Return `true` if the call path is a reference to `typing.${target}`.
pub fn match_typing_qualified_name(
&self,
qualified_name: &QualifiedName,
target: &str,
) -> bool {
if matches!(
qualified_name.segments(),
["typing" | "_typeshed" | "typing_extensions", member] if *member == target
) {
return true;
}
if self.typing_modules.iter().any(|module| {
let module = QualifiedName::user_defined(module);
qualified_name == &module.append_member(target)
}) {
return true;
}
false
}
/// Return an iterator over the set of `typing` modules allowed in the semantic model.
pub fn typing_modules(&self) -> impl Iterator<Item = &'a str> {
["typing", "_typeshed", "typing_extensions"]
.iter()
.copied()
.chain(self.typing_modules.iter().map(String::as_str))
}
/// Returns `true` if `name` is provided by the configured Python runtime.
///
/// This includes version- and source-type-specific builtins, magic globals, and custom
/// builtins. It does not account for bindings that shadow the name in a scope.
fn is_builtin_name(&self, name: &str) -> bool {
is_python_builtin(name, self.target_version.minor, self.source_type.is_ipynb())
|| python_magic_globals(self.target_version.minor).any(|builtin| builtin == name)
|| self.custom_builtins.iter().any(|builtin| builtin == name)
}
/// Creates and returns a concrete binding for an unmaterialized builtin.
fn materialize_builtin_binding(&mut self, name: &'a str) -> Option<BindingId> {
if let Some(binding_id) = self.global_scope().get(name) {
return self.bindings[binding_id]
.kind
.is_builtin()
.then_some(binding_id);
}
if !self.is_builtin_name(name) {
return None;
}
let binding_id = self.push_builtin();
self.global_scope_mut().add(name, binding_id);
Some(binding_id)
}
/// Create a new [`Binding`] for a builtin.
fn push_builtin(&mut self) -> BindingId {
self.bindings.push(Binding {
range: TextRange::default(),
kind: BindingKind::Builtin,
scope: ScopeId::global(),
references: Vec::new(),
flags: BindingFlags::empty(),
source: None,
context: ExecutionContext::Runtime,
exceptions: Exceptions::empty(),
})
}
/// Create a new [`Binding`] for the given `name` and `range`.
pub fn push_binding(
&mut self,
name: &'a str,
range: TextRange,
kind: BindingKind<'a>,
flags: BindingFlags,
) -> BindingId {
self.materialize_builtin_binding(name);
self.bindings.push(Binding {
range,
kind,
flags,
references: Vec::new(),
scope: self.scope_id,
source: self.node_id,
context: self.execution_context(),
exceptions: self.exceptions(),
})
}
/// Return the [`BindingId`] that the given [`BindingId`] shadows, if any.
///
/// Note that this will only return bindings that are shadowed by a binding in a parent scope.
pub fn shadowed_binding(&self, binding_id: BindingId) -> Option<BindingId> {
self.shadowed_bindings.get(&binding_id).copied()
}
/// Return `true` if `member` is bound as a builtin *in the scope we are currently visiting*.
///
/// Note that a "builtin binding" does *not* include explicit lookups via the `builtins`
/// module, e.g. `import builtins; builtins.open`. It *only* includes the bindings
/// that are pre-populated in Python's global scope before any imports have taken place.
pub fn has_builtin_binding(&self, member: &str) -> bool {
self.has_builtin_binding_in_scope(member, self.scope_id)
}
/// Return `true` if `member` is bound as a builtin *in a given scope*.
///
/// Note that a "builtin binding" does *not* include explicit lookups via the `builtins`
/// module, e.g. `import builtins; builtins.open`. It *only* includes the bindings
/// that are pre-populated in Python's global scope before any imports have taken place.
pub fn has_builtin_binding_in_scope(&self, member: &str, scope: ScopeId) -> bool {
match self.lookup_symbol_in_scope(member, scope, false) {
Symbol::Binding(binding_id) => self.bindings[binding_id].kind.is_builtin(),
Symbol::Builtin => true,
Symbol::Unbound => false,
}
}
/// If `expr` is a reference to a builtins symbol,
/// return the name of that symbol. Else, return `None`.
///
/// This method returns `true` both for "builtin bindings"
/// (present even without any imports, e.g. `open()`), and for explicit lookups
/// via the `builtins` module (e.g. `import builtins; builtins.open()`).
pub fn resolve_builtin_symbol<'expr>(&'a self, expr: &'expr Expr) -> Option<&'a str>
where
'expr: 'a,
{
// Fast path: we only need to worry about name expressions
if !self.seen_module(Modules::BUILTINS) {
let name = &expr.as_name_expr()?.id;
return if self.has_builtin_binding(name) {
Some(name)
} else {
None
};
}
// Slow path: we have to consider names and attributes
let qualified_name = self.resolve_qualified_name(expr)?;
match qualified_name.segments() {
["" | "builtins", name] => Some(*name),
_ => None,
}
}
/// Return `true` if `expr` is a reference to `builtins.$target`,
/// i.e. either `object` (where `object` is not overridden in the global scope),
/// or `builtins.object` (where `builtins` is imported as a module at the top level)
pub fn match_builtin_expr(&self, expr: &Expr, symbol: &str) -> bool {
debug_assert!(!symbol.contains('.'));
// fast path with more short-circuiting
if !self.seen_module(Modules::BUILTINS) {
let Expr::Name(ast::ExprName { id, .. }) = expr else {
return false;
};
return id == symbol && self.has_builtin_binding(symbol);
}
// slow path: we need to consider attribute accesses and aliased imports
let Some(qualified_name) = self.resolve_qualified_name(expr) else {
return false;
};
matches!(qualified_name.segments(), ["" | "builtins", name] if *name == symbol)
}
/// Return `true` if `member` is an "available" symbol, i.e., a symbol that has not been bound
/// in the current scope currently being visited, or in any containing scope.
pub fn is_available(&self, member: &str) -> bool {
self.is_available_in_scope(member, self.scope_id)
}
/// Return `true` if `member` is an "available" symbol in a given scope, i.e.,
/// a symbol that has not been bound in that current scope, or in any containing scope.
pub fn is_available_in_scope(&self, member: &str, scope_id: ScopeId) -> bool {
match self.lookup_symbol_in_scope(member, scope_id, false) {
Symbol::Binding(binding_id) => self.bindings[binding_id].kind.is_builtin(),
Symbol::Builtin | Symbol::Unbound => true,
}
}
/// Resolve a `del` reference to `symbol` at `range`.
pub fn resolve_del(&mut self, symbol: &'a str, range: TextRange) {
self.materialize_builtin_binding(symbol);
let is_unbound = self.scopes[self.scope_id]
.get(symbol)
.is_none_or(|binding_id| {
// Treat the deletion of a name as a reference to that name.
self.add_local_reference(binding_id, ExprContext::Del, range);
self.bindings[binding_id].is_unbound()
});
// If the binding is unbound, we need to add an unresolved reference.
if is_unbound {
self.unresolved_references.push(
range,
self.exceptions(),
None,
UnresolvedReferenceFlags::empty(),
);
}
}
/// Resolve a `load` reference to an [`ast::ExprName`].
pub fn resolve_load(&mut self, name: &'a ast::ExprName) -> ReadResult {
// PEP 563 indicates that if a forward reference can be resolved in the module scope, we
// should prefer it over local resolutions.
if self.in_forward_reference() {
if let Some(binding_id) = self.scopes.global().get(name.id.as_str()) {
if !self.bindings[binding_id].is_unbound() {
// Mark the binding as used.
let reference_id = self.resolved_references.push(
ScopeId::global(),
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
// Mark any submodule aliases as used.
if let Some(binding_id) =
self.resolve_submodule(name.id.as_str(), ScopeId::global(), binding_id)
{
let reference_id = self.resolved_references.push(
ScopeId::global(),
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
}
self.resolved_names.insert(name.into(), binding_id);
return ReadResult::Resolved(binding_id);
}
}
}
let mut import_starred = false;
let mut class_variables_visible = true;
for (index, scope_id) in self.scopes.ancestor_ids(self.scope_id).enumerate() {
let scope = &self.scopes[scope_id];
if scope.kind.is_class() {
// Do not allow usages of class symbols unless it is the immediate parent
// (excluding type scopes), e.g.:
//
// ```python
// class Foo:
// a = 0
//
// b = a # allowed
// def c(self, arg=a): # allowed
// print(arg)
//
// def d(self):
// print(a) # not allowed
// ```
if !class_variables_visible {
continue;
}
}
// Allow class variables to be visible for an additional scope level
// when a type scope is seen — this covers the type scope present between
// function and class definitions and their parent class scope.
//
// Also allow an additional level beyond that to cover the implicit
// `__class__` closure created around methods and enclosing the type scope.
class_variables_visible = matches!(
(scope.kind, index),
(ScopeKind::Type, 0) | (ScopeKind::DunderClassCell, 1)
);
if let Some(binding_id) = scope.get(name.id.as_str()) {
// Mark the binding as used.
let reference_id = self.resolved_references.push(
self.scope_id,
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
// Mark any submodule aliases as used.
if let Some(binding_id) =
self.resolve_submodule(name.id.as_str(), scope_id, binding_id)
{
let reference_id = self.resolved_references.push(
self.scope_id,
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
}
match self.bindings[binding_id].kind {
// Type annotations are generally not treated as resolved. For example, given:
//
// ```python
// name: str
// print(name)
// ```
//
// The `name` in `print(name)` should be treated as unresolved, but the `name` in
// `name: str` should be treated as used.
//
// There are two exceptions to this rule:
// 1. Stub files. In a stub file, it _is_ considered valid to resolve to a
// type annotation.
// 2. Bare annotations inside functions. Per PEP 526, these create local
// variables, so we stop searching outer scopes and resolve them as unbound
// locals (or not found, if accessed from a nested scope). The binding ID
// is recorded in the unresolved reference so the linter can suppress the
// error if a nested scope initializes the variable via `nonlocal`.
BindingKind::Annotation if !self.in_stub_file() => {
if self.scopes[self.bindings[binding_id].scope]
.kind
.is_function()
{
self.unresolved_references.push(
name.range,
self.exceptions(),
Some(binding_id),
UnresolvedReferenceFlags::empty(),
);
if index == 0 {
return ReadResult::UnboundLocal(binding_id);
}
return ReadResult::NotFound;
}
continue;
}
// If it's a deletion, don't treat it as resolved, since the name is now
// unbound. For example, given:
//
// ```python
// x = 1
// del x
// print(x)
// ```
//
// The `x` in `print(x)` should be treated as unresolved.
//
// Similarly, given:
//
// ```python
// try:
// pass
// except ValueError as x:
// pass
//
// print(x)
//
// The `x` in `print(x)` should be treated as unresolved.
BindingKind::Deletion => {
// In stub files, `del` is used to hide names from re-export
// while the name is still valid for use in type annotations
// within the same file. Since annotations are deferred in
// stubs, the `Deletion` binding is seen at resolve time even
// though the reference textually precedes the `del`. Resolve
// to the shadowed (pre-`del`) binding when available.
if self.in_stub_file() {
if let Some(shadowed_id) =
self.scopes[scope_id].shadowed_binding(binding_id)
{
// Only suppress F821 when the reference textually precedes
// the `del` statement. If `del` comes before the reference,
// the name is genuinely undefined at that point and F821
// should still fire.
let deletion_range = self.bindings[binding_id].range;
if !self.bindings[shadowed_id].is_unbound()
&& name.range.start() < deletion_range.start()
{
let reference_id = self.resolved_references.push(
self.scope_id,
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[shadowed_id].references.push(reference_id);
self.resolved_names.insert(name.into(), shadowed_id);
return ReadResult::Resolved(shadowed_id);
}
}
}
self.unresolved_references.push(
name.range,
self.exceptions(),
None,
UnresolvedReferenceFlags::empty(),
);
return ReadResult::UnboundLocal(binding_id);
}
BindingKind::UnboundException(None) => {
self.unresolved_references.push(
name.range,
self.exceptions(),
None,
UnresolvedReferenceFlags::empty(),
);
return ReadResult::UnboundLocal(binding_id);
}
// If we hit an unbound exception that shadowed a bound name, resole to the
// bound name. For example, given:
//
// ```python
// x = 1
//
// try:
// pass
// except ValueError as x:
// pass
//
// print(x)
// ```
//
// The `x` in `print(x)` should resolve to the `x` in `x = 1`.
BindingKind::UnboundException(Some(binding_id)) => {
// Mark the binding as used.
let reference_id = self.resolved_references.push(
self.scope_id,
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
// Mark any submodule aliases as used.
if let Some(binding_id) =
self.resolve_submodule(name.id.as_str(), scope_id, binding_id)
{
let reference_id = self.resolved_references.push(
self.scope_id,
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
}
self.resolved_names.insert(name.into(), binding_id);
return ReadResult::Resolved(binding_id);
}
BindingKind::Global(Some(binding_id))
| BindingKind::Nonlocal(binding_id, _) => {
// Mark the shadowed binding as used.
let reference_id = self.resolved_references.push(
self.scope_id,
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
// Treat it as resolved.
self.resolved_names.insert(name.into(), binding_id);
return ReadResult::Resolved(binding_id);
}
_ => {
// Otherwise, treat it as resolved.
self.resolved_names.insert(name.into(), binding_id);
return ReadResult::Resolved(binding_id);
}
}
}
// Allow usages of `__module__` and `__qualname__` within class scopes, e.g.:
//
// ```python
// class Foo:
// print(__qualname__)
// ```
//
// Intentionally defer this check to _after_ the standard `scope.get` logic, so that
// we properly attribute reads to overridden class members, e.g.:
//
// ```python
// class Foo:
// __qualname__ = "Bar"
// print(__qualname__)
// ```
if index == 0 && scope.kind.is_class() {
if matches!(name.id.as_str(), "__module__" | "__qualname__") {
return ReadResult::ImplicitGlobal;
}
}
import_starred = import_starred || scope.uses_star_imports();
}
if let Some(binding_id) = self.materialize_builtin_binding(name.id.as_str()) {
let reference_id = self.resolved_references.push(
self.scope_id,
self.node_id,
ExprContext::Load,
self.flags,
name.range,
);
self.bindings[binding_id].references.push(reference_id);
self.resolved_names.insert(name.into(), binding_id);
return ReadResult::Resolved(binding_id);
}
if import_starred {
self.unresolved_references.push(
name.range,
self.exceptions(),
None,
UnresolvedReferenceFlags::WILDCARD_IMPORT,
);
ReadResult::WildcardImport
} else {
self.unresolved_references.push(
name.range,
self.exceptions(),
None,
UnresolvedReferenceFlags::empty(),
);
ReadResult::NotFound
}
}
/// Lookup a symbol in the current scope without materializing lazy builtins.
pub fn lookup_symbol(&self, symbol: &str) -> Symbol {
self.lookup_symbol_in_scope(symbol, self.scope_id, self.in_forward_reference())
}
/// Lookup a concrete binding in the current scope.
///
/// If `symbol` resolves to an unmaterialized builtin, this creates its binding before
/// returning the [`BindingId`].
pub fn lookup_binding(&mut self, symbol: &'a str) -> Option<BindingId> {
self.lookup_binding_in_scope(symbol, self.scope_id, self.in_forward_reference())
}
/// Return a binding from the global scope, materializing it first if it is a builtin.
pub fn global_binding(&mut self, symbol: &'a str) -> Option<BindingId> {
self.materialize_builtin_binding(symbol);
self.global_scope().get(symbol)
}
/// Lookup a concrete binding in a certain scope.
///
/// If `symbol` resolves to an unmaterialized builtin, this creates its binding before
/// returning the [`BindingId`].
fn lookup_binding_in_scope(
&mut self,
symbol: &'a str,
scope_id: ScopeId,
in_forward_reference: bool,
) -> Option<BindingId> {
match self.lookup_symbol_in_scope(symbol, scope_id, in_forward_reference) {
Symbol::Binding(binding_id) => Some(binding_id),
Symbol::Builtin => self.materialize_builtin_binding(symbol),
Symbol::Unbound => None,
}
}
/// Lookup a symbol in a certain scope without materializing lazy builtins.
///
/// This is a carbon copy of [`Self::resolve_load`], but
/// doesn't add any read references to the resolved symbol.
pub fn lookup_symbol_in_scope(
&self,
symbol: &str,
scope_id: ScopeId,
in_forward_reference: bool,
) -> Symbol {
if in_forward_reference {
if let Some(binding_id) = self.scopes.global().get(symbol) {
if !self.bindings[binding_id].is_unbound() {
return Symbol::Binding(binding_id);
}
}
}
let mut class_variables_visible = true;
for (index, scope_id) in self.scopes.ancestor_ids(scope_id).enumerate() {
let scope = &self.scopes[scope_id];
if scope.kind.is_class() {
if !class_variables_visible {
continue;
}
}
class_variables_visible = matches!(
(scope.kind, index),
(ScopeKind::Type, 0) | (ScopeKind::DunderClassCell, 1)
);
if let Some(binding_id) = scope.get(symbol) {
match self.bindings[binding_id].kind {
BindingKind::Annotation => continue,
BindingKind::Deletion | BindingKind::UnboundException(None) => {
return Symbol::Unbound;
}
BindingKind::UnboundException(Some(binding_id)) => {
return Symbol::Binding(binding_id);
}
_ => return Symbol::Binding(binding_id),
}
}
if index == 0 && scope.kind.is_class() {
if matches!(symbol, "__module__" | "__qualname__") {
return Symbol::Unbound;
}
}
}
if self.is_builtin_name(symbol) {
Symbol::Builtin
} else {
Symbol::Unbound
}
}
/// Simulates a runtime load of a given [`ast::ExprName`].
///
/// This should not be run until after all the bindings have been visited.
///
/// The main purpose of this method and what makes this different
/// from methods like [`SemanticModel::lookup_symbol`] and
/// [`SemanticModel::resolve_name`] is that it may be used
/// to perform speculative name lookups.
///
/// In most cases a load can be accurately modeled simply by calling
/// [`SemanticModel::resolve_name`] at the right time during semantic
/// analysis, however for speculative lookups this is not the case,
/// since we're aiming to change the semantic meaning of our load.
/// E.g. we want to check what would happen if we changed a forward
/// reference to an immediate load or vice versa.
///
/// Use caution when utilizing this method, since it was primarily designed
/// to work for speculative lookups from within type definitions, which
/// happen to share some nice properties, where attaching each binding
/// to a range in the source code and ordering those bindings based on
/// that range is a good enough approximation of which bindings are
/// available at runtime for which reference.
///
/// References from within an [`ast::Comprehension`] can produce incorrect
/// results when referring to a [`BindingKind::NamedExprAssignment`].
pub fn simulate_runtime_load(
&self,
name: &ast::ExprName,
typing_only_bindings_status: TypingOnlyBindingsStatus,
) -> Option<BindingId> {
self.simulate_runtime_load_at_location_in_scope(
name.id.as_str(),
name.range,
self.scope_id,
typing_only_bindings_status,
)
}
/// Simulates a runtime load of the given symbol.
///
/// This should not be run until after all the bindings have been visited.
///
/// The main purpose of this method and what makes this different from
/// [`SemanticModel::lookup_symbol_in_scope`] is that it may be used to
/// perform speculative name lookups.
///
/// In most cases a load can be accurately modeled simply by calling
/// [`SemanticModel::lookup_symbol`] at the right time during semantic
/// analysis, however for speculative lookups this is not the case,
/// since we're aiming to change the semantic meaning of our load.
/// E.g. we want to check what would happen if we changed a forward
/// reference to an immediate load or vice versa.
///
/// Use caution when utilizing this method, since it was primarily designed
/// to work for speculative lookups from within type definitions, which
/// happen to share some nice properties, where attaching each binding
/// to a range in the source code and ordering those bindings based on
/// that range is a good enough approximation of which bindings are
/// available at runtime for which reference.
///
/// References from within an [`ast::Comprehension`] can produce incorrect
/// results when referring to a [`BindingKind::NamedExprAssignment`].
pub fn simulate_runtime_load_at_location_in_scope(
&self,
symbol: &str,
symbol_range: TextRange,
scope_id: ScopeId,
typing_only_bindings_status: TypingOnlyBindingsStatus,
) -> Option<BindingId> {
let mut seen_function = false;
let mut class_variables_visible = true;
let mut source_order_sensitive_lookup = true;
for (index, scope_id) in self.scopes.ancestor_ids(scope_id).enumerate() {
let scope = &self.scopes[scope_id];
// Only once we leave a function scope and its enclosing type scope should
// we stop doing source-order lookups. We could e.g. have nested classes
// where we lookup symbols from the innermost class scope, which can only see
// things from the outer class(es) that have been defined before the inner
// class. Source-order lookups take advantage of the fact that most of the
// bindings are created sequentially in source order, so if we want to
// determine whether or not a given reference can refer to another binding
// we can look at their text ranges to check whether or not the binding
// could actually be referred to. This is not as robust as back-tracking
// the AST, since that can properly take care of the few out-of order
// corner-cases, but back-tracking the AST from the reference to the binding
// is a lot more expensive than comparing a pair of text ranges.
if seen_function && !scope.kind.is_type() {
source_order_sensitive_lookup = false;
}
if scope.kind.is_class() {
if !class_variables_visible {
continue;
}
}
class_variables_visible = matches!(
(scope.kind, index),
(ScopeKind::Type, 0) | (ScopeKind::DunderClassCell, 1)
);
seen_function |= scope.kind.is_function();
if let Some(binding_id) = scope.get(symbol) {
if source_order_sensitive_lookup {
// we need to look through all the shadowed bindings
// since we may be shadowing a source-order accurate
// runtime binding with a source-order inaccurate one
for shadowed_id in scope.shadowed_bindings(binding_id) {
let binding = &self.bindings[shadowed_id];
if typing_only_bindings_status.is_disallowed()
&& binding.context.is_typing()