ruff/crates/red_knot/src/semantic.rs

883 lines
32 KiB
Rust

use std::num::NonZeroU32;
use ruff_python_ast as ast;
use ruff_python_ast::visitor::source_order::SourceOrderVisitor;
use ruff_python_ast::AstNode;
use crate::ast_ids::{NodeKey, TypedNodeKey};
use crate::cache::KeyValueCache;
use crate::db::{QueryResult, SemanticDb, SemanticJar};
use crate::files::FileId;
use crate::module::Module;
use crate::module::ModuleName;
use crate::parse::parse;
use crate::Name;
pub(crate) use definitions::Definition;
use definitions::{ImportDefinition, ImportFromDefinition};
pub(crate) use flow_graph::ConstrainedDefinition;
use flow_graph::{FlowGraph, FlowGraphBuilder, FlowNodeId, ReachableDefinitionsIterator};
use ruff_index::{newtype_index, IndexVec};
use rustc_hash::FxHashMap;
use std::ops::{Deref, DerefMut};
use std::sync::Arc;
pub(crate) use symbol_table::{Dependency, SymbolId};
use symbol_table::{ScopeId, ScopeKind, SymbolFlags, SymbolTable, SymbolTableBuilder};
pub(crate) use types::{infer_definition_type, infer_symbol_public_type, Type, TypeStore};
mod definitions;
mod flow_graph;
mod symbol_table;
mod types;
#[tracing::instrument(level = "debug", skip(db))]
pub fn semantic_index(db: &dyn SemanticDb, file_id: FileId) -> QueryResult<Arc<SemanticIndex>> {
let jar: &SemanticJar = db.jar()?;
jar.semantic_indices.get(&file_id, |_| {
let parsed = parse(db.upcast(), file_id)?;
Ok(Arc::from(SemanticIndex::from_ast(parsed.syntax())))
})
}
#[tracing::instrument(level = "debug", skip(db))]
pub fn resolve_global_symbol(
db: &dyn SemanticDb,
module: Module,
name: &str,
) -> QueryResult<Option<GlobalSymbolId>> {
let file_id = module.path(db)?.file();
let symbol_table = &semantic_index(db, file_id)?.symbol_table;
let Some(symbol_id) = symbol_table.root_symbol_id_by_name(name) else {
return Ok(None);
};
Ok(Some(GlobalSymbolId { file_id, symbol_id }))
}
#[newtype_index]
pub struct ExpressionId;
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub struct GlobalSymbolId {
pub(crate) file_id: FileId,
pub(crate) symbol_id: SymbolId,
}
#[derive(Debug)]
pub struct SemanticIndex {
symbol_table: SymbolTable,
flow_graph: FlowGraph,
expressions: FxHashMap<NodeKey, ExpressionId>,
expressions_by_id: IndexVec<ExpressionId, NodeKey>,
}
impl SemanticIndex {
pub fn from_ast(module: &ast::ModModule) -> Self {
let root_scope_id = SymbolTable::root_scope_id();
let mut indexer = SemanticIndexer {
symbol_table_builder: SymbolTableBuilder::new(),
flow_graph_builder: FlowGraphBuilder::new(),
scopes: vec![ScopeState {
scope_id: root_scope_id,
current_flow_node_id: FlowGraph::start(),
}],
expressions: FxHashMap::default(),
expressions_by_id: IndexVec::default(),
current_definition: None,
};
indexer.visit_body(&module.body);
indexer.finish()
}
fn resolve_expression_id<'a>(
&self,
ast: &'a ast::ModModule,
expression_id: ExpressionId,
) -> ast::AnyNodeRef<'a> {
let node_key = self.expressions_by_id[expression_id];
node_key
.resolve(ast.as_any_node_ref())
.expect("node to resolve")
}
/// Return an iterator over all definitions of `symbol_id` reachable from `use_expr`. The value
/// of `symbol_id` in `use_expr` must originate from one of the iterated definitions (or from
/// an external reassignment of the name outside of this scope).
pub fn reachable_definitions(
&self,
symbol_id: SymbolId,
use_expr: &ast::Expr,
) -> ReachableDefinitionsIterator {
let expression_id = self.expression_id(use_expr);
ReachableDefinitionsIterator::new(
&self.flow_graph,
symbol_id,
self.flow_graph.for_expr(expression_id),
)
}
pub fn expression_id(&self, expression: &ast::Expr) -> ExpressionId {
self.expressions[&NodeKey::from_node(expression.into())]
}
pub fn symbol_table(&self) -> &SymbolTable {
&self.symbol_table
}
}
#[derive(Debug)]
struct ScopeState {
scope_id: ScopeId,
current_flow_node_id: FlowNodeId,
}
#[derive(Debug)]
struct SemanticIndexer {
symbol_table_builder: SymbolTableBuilder,
flow_graph_builder: FlowGraphBuilder,
scopes: Vec<ScopeState>,
/// the definition whose target(s) we are currently walking
current_definition: Option<Definition>,
expressions: FxHashMap<NodeKey, ExpressionId>,
expressions_by_id: IndexVec<ExpressionId, NodeKey>,
}
impl SemanticIndexer {
pub(crate) fn finish(mut self) -> SemanticIndex {
let SemanticIndexer {
flow_graph_builder,
symbol_table_builder,
..
} = self;
self.expressions.shrink_to_fit();
self.expressions_by_id.shrink_to_fit();
SemanticIndex {
flow_graph: flow_graph_builder.finish(),
symbol_table: symbol_table_builder.finish(),
expressions: self.expressions,
expressions_by_id: self.expressions_by_id,
}
}
fn set_current_flow_node(&mut self, new_flow_node_id: FlowNodeId) {
let scope_state = self.scopes.last_mut().expect("scope stack is never empty");
scope_state.current_flow_node_id = new_flow_node_id;
}
fn current_flow_node(&self) -> FlowNodeId {
self.scopes
.last()
.expect("scope stack is never empty")
.current_flow_node_id
}
fn add_or_update_symbol(&mut self, identifier: &str, flags: SymbolFlags) -> SymbolId {
self.symbol_table_builder
.add_or_update_symbol(self.cur_scope(), identifier, flags)
}
fn add_or_update_symbol_with_def(
&mut self,
identifier: &str,
definition: Definition,
) -> SymbolId {
let symbol_id = self.add_or_update_symbol(identifier, SymbolFlags::IS_DEFINED);
self.symbol_table_builder
.add_definition(symbol_id, definition.clone());
let new_flow_node_id =
self.flow_graph_builder
.add_definition(symbol_id, definition, self.current_flow_node());
self.set_current_flow_node(new_flow_node_id);
symbol_id
}
fn push_scope(
&mut self,
name: &str,
kind: ScopeKind,
definition: Option<Definition>,
defining_symbol: Option<SymbolId>,
) -> ScopeId {
let scope_id = self.symbol_table_builder.add_child_scope(
self.cur_scope(),
name,
kind,
definition,
defining_symbol,
);
self.scopes.push(ScopeState {
scope_id,
current_flow_node_id: FlowGraph::start(),
});
scope_id
}
fn pop_scope(&mut self) -> ScopeId {
self.scopes
.pop()
.expect("Scope stack should never be empty")
.scope_id
}
fn cur_scope(&self) -> ScopeId {
self.scopes
.last()
.expect("Scope stack should never be empty")
.scope_id
}
fn record_scope_for_node(&mut self, node_key: NodeKey, scope_id: ScopeId) {
self.symbol_table_builder
.record_scope_for_node(node_key, scope_id);
}
fn insert_constraint(&mut self, expr: &ast::Expr) {
let node_key = NodeKey::from_node(expr.into());
let expression_id = self.expressions[&node_key];
let constraint = self
.flow_graph_builder
.add_constraint(self.current_flow_node(), expression_id);
self.set_current_flow_node(constraint);
}
fn with_type_params(
&mut self,
name: &str,
params: &Option<Box<ast::TypeParams>>,
definition: Option<Definition>,
defining_symbol: Option<SymbolId>,
nested: impl FnOnce(&mut Self) -> ScopeId,
) -> ScopeId {
if let Some(type_params) = params {
self.push_scope(name, ScopeKind::Annotation, definition, defining_symbol);
for type_param in &type_params.type_params {
let name = match type_param {
ast::TypeParam::TypeVar(ast::TypeParamTypeVar { name, .. }) => name,
ast::TypeParam::ParamSpec(ast::TypeParamParamSpec { name, .. }) => name,
ast::TypeParam::TypeVarTuple(ast::TypeParamTypeVarTuple { name, .. }) => name,
};
self.add_or_update_symbol(name, SymbolFlags::IS_DEFINED);
}
}
let scope_id = nested(self);
if params.is_some() {
self.pop_scope();
}
scope_id
}
}
impl SourceOrderVisitor<'_> for SemanticIndexer {
fn visit_expr(&mut self, expr: &ast::Expr) {
let node_key = NodeKey::from_node(expr.into());
let expression_id = self.expressions_by_id.push(node_key);
let flow_expression_id = self
.flow_graph_builder
.record_expr(self.current_flow_node());
debug_assert_eq!(expression_id, flow_expression_id);
let symbol_expression_id = self
.symbol_table_builder
.record_expression(self.cur_scope());
debug_assert_eq!(expression_id, symbol_expression_id);
self.expressions.insert(node_key, expression_id);
match expr {
ast::Expr::Name(ast::ExprName { id, ctx, .. }) => {
let flags = match ctx {
ast::ExprContext::Load => SymbolFlags::IS_USED,
ast::ExprContext::Store => SymbolFlags::IS_DEFINED,
ast::ExprContext::Del => SymbolFlags::IS_DEFINED,
ast::ExprContext::Invalid => SymbolFlags::empty(),
};
self.add_or_update_symbol(id, flags);
if flags.contains(SymbolFlags::IS_DEFINED) {
if let Some(curdef) = self.current_definition.clone() {
self.add_or_update_symbol_with_def(id, curdef);
}
}
ast::visitor::source_order::walk_expr(self, expr);
}
ast::Expr::Named(node) => {
debug_assert!(self.current_definition.is_none());
self.current_definition =
Some(Definition::NamedExpr(TypedNodeKey::from_node(node)));
// TODO walrus in comprehensions is implicitly nonlocal
self.visit_expr(&node.target);
self.current_definition = None;
self.visit_expr(&node.value);
}
ast::Expr::If(ast::ExprIf {
body, test, orelse, ..
}) => {
// TODO detect statically known truthy or falsy test (via type inference, not naive
// AST inspection, so we can't simplify here, need to record test expression in CFG
// for later checking)
self.visit_expr(test);
let if_branch = self.flow_graph_builder.add_branch(self.current_flow_node());
self.set_current_flow_node(if_branch);
self.insert_constraint(test);
self.visit_expr(body);
let post_body = self.current_flow_node();
self.set_current_flow_node(if_branch);
self.visit_expr(orelse);
let post_else = self
.flow_graph_builder
.add_phi(self.current_flow_node(), post_body);
self.set_current_flow_node(post_else);
}
_ => {
ast::visitor::source_order::walk_expr(self, expr);
}
}
}
fn visit_stmt(&mut self, stmt: &ast::Stmt) {
// TODO need to capture more definition statements here
match stmt {
ast::Stmt::ClassDef(node) => {
let node_key = TypedNodeKey::from_node(node);
let def = Definition::ClassDef(node_key.clone());
let symbol_id = self.add_or_update_symbol_with_def(&node.name, def.clone());
for decorator in &node.decorator_list {
self.visit_decorator(decorator);
}
let scope_id = self.with_type_params(
&node.name,
&node.type_params,
Some(def.clone()),
Some(symbol_id),
|indexer| {
if let Some(arguments) = &node.arguments {
indexer.visit_arguments(arguments);
}
let scope_id = indexer.push_scope(
&node.name,
ScopeKind::Class,
Some(def.clone()),
Some(symbol_id),
);
indexer.visit_body(&node.body);
indexer.pop_scope();
scope_id
},
);
self.record_scope_for_node(*node_key.erased(), scope_id);
}
ast::Stmt::FunctionDef(node) => {
let node_key = TypedNodeKey::from_node(node);
let def = Definition::FunctionDef(node_key.clone());
let symbol_id = self.add_or_update_symbol_with_def(&node.name, def.clone());
for decorator in &node.decorator_list {
self.visit_decorator(decorator);
}
let scope_id = self.with_type_params(
&node.name,
&node.type_params,
Some(def.clone()),
Some(symbol_id),
|indexer| {
indexer.visit_parameters(&node.parameters);
for expr in &node.returns {
indexer.visit_annotation(expr);
}
let scope_id = indexer.push_scope(
&node.name,
ScopeKind::Function,
Some(def.clone()),
Some(symbol_id),
);
indexer.visit_body(&node.body);
indexer.pop_scope();
scope_id
},
);
self.record_scope_for_node(*node_key.erased(), scope_id);
}
ast::Stmt::Import(ast::StmtImport { names, .. }) => {
for alias in names {
let symbol_name = if let Some(asname) = &alias.asname {
asname.id.as_str()
} else {
alias.name.id.split('.').next().unwrap()
};
let module = ModuleName::new(&alias.name.id);
let def = Definition::Import(ImportDefinition {
module: module.clone(),
});
self.add_or_update_symbol_with_def(symbol_name, def);
self.symbol_table_builder
.add_dependency(Dependency::Module(module));
}
}
ast::Stmt::ImportFrom(ast::StmtImportFrom {
module,
names,
level,
..
}) => {
let module = module.as_ref().map(|m| ModuleName::new(&m.id));
for alias in names {
let symbol_name = if let Some(asname) = &alias.asname {
asname.id.as_str()
} else {
alias.name.id.as_str()
};
let def = Definition::ImportFrom(ImportFromDefinition {
module: module.clone(),
name: Name::new(&alias.name.id),
level: *level,
});
self.add_or_update_symbol_with_def(symbol_name, def);
}
let dependency = if let Some(module) = module {
match NonZeroU32::new(*level) {
Some(level) => Dependency::Relative {
level,
module: Some(module),
},
None => Dependency::Module(module),
}
} else {
Dependency::Relative {
level: NonZeroU32::new(*level)
.expect("Import without a module to have a level > 0"),
module,
}
};
self.symbol_table_builder.add_dependency(dependency);
}
ast::Stmt::Assign(node) => {
debug_assert!(self.current_definition.is_none());
self.visit_expr(&node.value);
self.current_definition =
Some(Definition::Assignment(TypedNodeKey::from_node(node)));
for expr in &node.targets {
self.visit_expr(expr);
}
self.current_definition = None;
}
ast::Stmt::If(node) => {
// TODO detect statically known truthy or falsy test (via type inference, not naive
// AST inspection, so we can't simplify here, need to record test expression in CFG
// for later checking)
// we visit the if "test" condition first regardless
self.visit_expr(&node.test);
// create branch node: does the if test pass or not?
let if_branch = self.flow_graph_builder.add_branch(self.current_flow_node());
// visit the body of the `if` clause
self.set_current_flow_node(if_branch);
self.insert_constraint(&node.test);
self.visit_body(&node.body);
// Flow node for the last if/elif condition branch; represents the "no branch
// taken yet" possibility (where "taking a branch" means that the condition in an
// if or elif evaluated to true and control flow went into that clause).
let mut prior_branch = if_branch;
// Flow node for the state after the prior if/elif/else clause; represents "we have
// taken one of the branches up to this point." Initially set to the post-if-clause
// state, later will be set to the phi node joining that possible path with the
// possibility that we took a later if/elif/else clause instead.
let mut post_prior_clause = self.current_flow_node();
// Flag to mark if the final clause is an "else" -- if so, that means the "match no
// clauses" path is not possible, we have to go through one of the clauses.
let mut last_branch_is_else = false;
for clause in &node.elif_else_clauses {
if let Some(test) = &clause.test {
self.visit_expr(test);
// This is an elif clause. Create a new branch node. Its predecessor is the
// previous branch node, because we can only take one branch in an entire
// if/elif/else chain, so if we take this branch, it can only be because we
// didn't take the previous one.
prior_branch = self.flow_graph_builder.add_branch(prior_branch);
self.set_current_flow_node(prior_branch);
self.insert_constraint(test);
} else {
// This is an else clause. No need to create a branch node; there's no
// branch here, if we haven't taken any previous branch, we definitely go
// into the "else" clause.
self.set_current_flow_node(prior_branch);
last_branch_is_else = true;
}
self.visit_elif_else_clause(clause);
// Update `post_prior_clause` to a new phi node joining the possibility that we
// took any of the previous branches with the possibility that we took the one
// just visited.
post_prior_clause = self
.flow_graph_builder
.add_phi(self.current_flow_node(), post_prior_clause);
}
if !last_branch_is_else {
// Final branch was not an "else", which means it's possible we took zero
// branches in the entire if/elif chain, so we need one more phi node to join
// the "no branches taken" possibility.
post_prior_clause = self
.flow_graph_builder
.add_phi(post_prior_clause, prior_branch);
}
// Onward, with current flow node set to our final Phi node.
self.set_current_flow_node(post_prior_clause);
}
_ => {
ast::visitor::source_order::walk_stmt(self, stmt);
}
}
}
}
#[derive(Debug, Default)]
pub struct SemanticIndexStorage(KeyValueCache<FileId, Arc<SemanticIndex>>);
impl Deref for SemanticIndexStorage {
type Target = KeyValueCache<FileId, Arc<SemanticIndex>>;
fn deref(&self) -> &Self::Target {
&self.0
}
}
impl DerefMut for SemanticIndexStorage {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.0
}
}
#[cfg(test)]
mod tests {
use crate::semantic::symbol_table::{Symbol, SymbolIterator};
use ruff_python_ast as ast;
use ruff_python_ast::ModModule;
use ruff_python_parser::{Mode, Parsed};
use super::{Definition, ScopeKind, SemanticIndex, SymbolId};
fn parse(code: &str) -> Parsed<ModModule> {
ruff_python_parser::parse_unchecked(code, Mode::Module)
.try_into_module()
.unwrap()
}
fn names<I>(it: SymbolIterator<I>) -> Vec<&str>
where
I: Iterator<Item = SymbolId>,
{
let mut symbols: Vec<_> = it.map(Symbol::name).collect();
symbols.sort_unstable();
symbols
}
#[test]
fn empty() {
let parsed = parse("");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()).len(), 0);
}
#[test]
fn simple() {
let parsed = parse("x");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["x"]);
assert_eq!(
table
.definitions(table.root_symbol_id_by_name("x").unwrap())
.len(),
0
);
}
#[test]
fn annotation_only() {
let parsed = parse("x: int");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["int", "x"]);
// TODO record definition
}
#[test]
fn import() {
let parsed = parse("import foo");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["foo"]);
assert_eq!(
table
.definitions(table.root_symbol_id_by_name("foo").unwrap())
.len(),
1
);
}
#[test]
fn import_sub() {
let parsed = parse("import foo.bar");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["foo"]);
}
#[test]
fn import_as() {
let parsed = parse("import foo.bar as baz");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["baz"]);
}
#[test]
fn import_from() {
let parsed = parse("from bar import foo");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["foo"]);
assert_eq!(
table
.definitions(table.root_symbol_id_by_name("foo").unwrap())
.len(),
1
);
assert!(
table.root_symbol_id_by_name("foo").is_some_and(|sid| {
let s = sid.symbol(&table);
s.is_defined() || !s.is_used()
}),
"symbols that are defined get the defined flag"
);
}
#[test]
fn assign() {
let parsed = parse("x = foo");
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["foo", "x"]);
assert_eq!(
table
.definitions(table.root_symbol_id_by_name("x").unwrap())
.len(),
1
);
assert!(
table.root_symbol_id_by_name("foo").is_some_and(|sid| {
let s = sid.symbol(&table);
!s.is_defined() && s.is_used()
}),
"a symbol used but not defined in a scope should have only the used flag"
);
}
#[test]
fn class_scope() {
let parsed = parse(
"
class C:
x = 1
y = 2
",
);
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["C", "y"]);
let scopes = table.root_child_scope_ids();
assert_eq!(scopes.len(), 1);
let c_scope = scopes[0].scope(&table);
assert_eq!(c_scope.kind(), ScopeKind::Class);
assert_eq!(c_scope.name(), "C");
assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
assert_eq!(
table
.definitions(table.root_symbol_id_by_name("C").unwrap())
.len(),
1
);
}
#[test]
fn func_scope() {
let parsed = parse(
"
def func():
x = 1
y = 2
",
);
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["func", "y"]);
let scopes = table.root_child_scope_ids();
assert_eq!(scopes.len(), 1);
let func_scope = scopes[0].scope(&table);
assert_eq!(func_scope.kind(), ScopeKind::Function);
assert_eq!(func_scope.name(), "func");
assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
assert_eq!(
table
.definitions(table.root_symbol_id_by_name("func").unwrap())
.len(),
1
);
}
#[test]
fn dupes() {
let parsed = parse(
"
def func():
x = 1
def func():
y = 2
",
);
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["func"]);
let scopes = table.root_child_scope_ids();
assert_eq!(scopes.len(), 2);
let func_scope_1 = scopes[0].scope(&table);
let func_scope_2 = scopes[1].scope(&table);
assert_eq!(func_scope_1.kind(), ScopeKind::Function);
assert_eq!(func_scope_1.name(), "func");
assert_eq!(func_scope_2.kind(), ScopeKind::Function);
assert_eq!(func_scope_2.name(), "func");
assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
assert_eq!(names(table.symbols_for_scope(scopes[1])), vec!["y"]);
assert_eq!(
table
.definitions(table.root_symbol_id_by_name("func").unwrap())
.len(),
2
);
}
#[test]
fn generic_func() {
let parsed = parse(
"
def func[T]():
x = 1
",
);
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["func"]);
let scopes = table.root_child_scope_ids();
assert_eq!(scopes.len(), 1);
let ann_scope_id = scopes[0];
let ann_scope = ann_scope_id.scope(&table);
assert_eq!(ann_scope.kind(), ScopeKind::Annotation);
assert_eq!(ann_scope.name(), "func");
assert_eq!(names(table.symbols_for_scope(ann_scope_id)), vec!["T"]);
let scopes = table.child_scope_ids_of(ann_scope_id);
assert_eq!(scopes.len(), 1);
let func_scope_id = scopes[0];
let func_scope = func_scope_id.scope(&table);
assert_eq!(func_scope.kind(), ScopeKind::Function);
assert_eq!(func_scope.name(), "func");
assert_eq!(names(table.symbols_for_scope(func_scope_id)), vec!["x"]);
}
#[test]
fn generic_class() {
let parsed = parse(
"
class C[T]:
x = 1
",
);
let table = SemanticIndex::from_ast(parsed.syntax()).symbol_table;
assert_eq!(names(table.root_symbols()), vec!["C"]);
let scopes = table.root_child_scope_ids();
assert_eq!(scopes.len(), 1);
let ann_scope_id = scopes[0];
let ann_scope = ann_scope_id.scope(&table);
assert_eq!(ann_scope.kind(), ScopeKind::Annotation);
assert_eq!(ann_scope.name(), "C");
assert_eq!(names(table.symbols_for_scope(ann_scope_id)), vec!["T"]);
assert!(
table
.symbol_by_name(ann_scope_id, "T")
.is_some_and(|s| s.is_defined() && !s.is_used()),
"type parameters are defined by the scope that introduces them"
);
let scopes = table.child_scope_ids_of(ann_scope_id);
assert_eq!(scopes.len(), 1);
let func_scope_id = scopes[0];
let func_scope = func_scope_id.scope(&table);
assert_eq!(func_scope.kind(), ScopeKind::Class);
assert_eq!(func_scope.name(), "C");
assert_eq!(names(table.symbols_for_scope(func_scope_id)), vec!["x"]);
}
#[test]
fn reachability_trivial() {
let parsed = parse("x = 1; x");
let ast = parsed.syntax();
let index = SemanticIndex::from_ast(ast);
let table = &index.symbol_table;
let x_sym = table
.root_symbol_id_by_name("x")
.expect("x symbol should exist");
let ast::Stmt::Expr(ast::StmtExpr { value: x_use, .. }) = &ast.body[1] else {
panic!("should be an expr")
};
let x_defs: Vec<_> = index
.reachable_definitions(x_sym, x_use)
.map(|constrained_definition| constrained_definition.definition)
.collect();
assert_eq!(x_defs.len(), 1);
let Definition::Assignment(node_key) = &x_defs[0] else {
panic!("def should be an assignment")
};
let Some(def_node) = node_key.resolve(ast.into()) else {
panic!("node key should resolve")
};
let ast::Expr::NumberLiteral(ast::ExprNumberLiteral {
value: ast::Number::Int(num),
..
}) = &*def_node.value
else {
panic!("should be a number literal")
};
assert_eq!(*num, 1);
}
#[test]
fn expression_scope() {
let parsed = parse("x = 1;\ndef test():\n y = 4");
let ast = parsed.syntax();
let index = SemanticIndex::from_ast(ast);
let table = &index.symbol_table;
let x_sym = table
.root_symbol_by_name("x")
.expect("x symbol should exist");
let x_stmt = ast.body[0].as_assign_stmt().unwrap();
let x_id = index.expression_id(&x_stmt.targets[0]);
assert_eq!(table.scope_of_expression(x_id).kind(), ScopeKind::Module);
assert_eq!(table.scope_id_of_expression(x_id), x_sym.scope_id());
let def = ast.body[1].as_function_def_stmt().unwrap();
let y_stmt = def.body[0].as_assign_stmt().unwrap();
let y_id = index.expression_id(&y_stmt.targets[0]);
assert_eq!(table.scope_of_expression(y_id).kind(), ScopeKind::Function);
}
}