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//! Overload-resolution helpers shared by the function-call validator: per-
//! overload match testing, mutable-argument convention checks, and qualified-
//! path lookup through nested module symbol tables.
use super::super::super::module_resolver::ModuleResolver;
use super::super::super::sem_type::SemType;
use super::super::super::SemanticAnalyzer;
use crate::ast::File;
use crate::error::CompilerError;
use crate::location::Span;
impl<R: ModuleResolver> SemanticAnalyzer<R> {
/// For each `mut`-convention parameter, verify the corresponding call argument is mutable.
pub(super) fn validate_mut_param_args(
&mut self,
params: &[crate::semantic::symbol_table::ParamInfo],
args: &[(Option<crate::ast::Ident>, crate::ast::Expr)],
span: Span,
file: &File,
) {
use crate::ast::ParamConvention;
let non_self: Vec<_> = params.iter().filter(|p| p.name.name != "self").collect();
for (i, (label_opt, arg_expr)) in args.iter().enumerate() {
let param = label_opt.as_ref().map_or_else(
|| non_self.get(i).copied(),
|label| {
non_self
.iter()
.find(|p| {
p.external_label
.as_ref()
.is_some_and(|l| l.name == label.name)
|| p.name.name == label.name
})
.map(|v| &**v)
},
);
if let Some(param) = param {
if param.convention == ParamConvention::Mut && !self.is_expr_mutable(arg_expr, file)
{
self.errors.push(CompilerError::MutabilityMismatch {
param: param.name.name.clone(),
span,
});
}
if param.convention == ParamConvention::Sink {
if let Some(root) = Self::root_binding(arg_expr) {
self.consumed_bindings.insert(root);
}
// Escape analysis: a closure value passed to a sink param
// escapes with its captures — mark them consumed.
self.escape_closure_value(arg_expr);
}
}
}
}
/// Check whether a single overload matches the given call arguments.
///
/// Resolution order:
/// 1. If all call arguments have labels, match by label set.
/// 2. If no call arguments have labels, try to match by first-argument type.
pub(super) fn overload_matches(
&self,
overload: &crate::semantic::symbol_table::FunctionInfo,
call_labels: &[Option<String>],
args: &[(Option<crate::ast::Ident>, crate::ast::Expr)],
file: &File,
) -> bool {
let params = &overload.params;
// Collect overload parameter labels (external_label if set, else param name)
let param_labels: Vec<String> = params
.iter()
.filter(|p| p.name.name != "self")
.map(|p| {
p.external_label
.as_ref()
.map_or_else(|| p.name.name.clone(), |l| l.name.clone())
})
.collect();
let all_labeled = call_labels.iter().all(Option::is_some);
let none_labeled = call_labels.iter().all(Option::is_none);
if all_labeled && !call_labels.is_empty() {
// Mode A: match by label set, accepting omitted parameters
// when they have defaults. Required = labels without defaults.
// The call's labels must be a subset of param_labels covering
// every required label.
let call_label_set: std::collections::HashSet<&str> =
call_labels.iter().filter_map(|l| l.as_deref()).collect();
let required_labels: std::collections::HashSet<&str> = params
.iter()
.filter(|p| p.name.name != "self" && p.default.is_none())
.map(|p| {
p.external_label
.as_ref()
.map_or(p.name.name.as_str(), |l| l.name.as_str())
})
.collect();
let param_label_set: std::collections::HashSet<&str> =
param_labels.iter().map(String::as_str).collect();
// Every call label must exist on the param; every required
// label must be present in the call.
call_label_set.iter().all(|l| param_label_set.contains(l))
&& required_labels.iter().all(|l| call_label_set.contains(l))
} else if none_labeled && args.is_empty() {
// Zero-arg call: matches a zero-required-arg overload. With
// default values, an overload with all defaults (e.g.
// `fn f(x: I32 = 0)`) also matches a zero-arg call.
// Without context-type disambiguation (e.g., from a let
// annotation), multiple zero-required-arg overloads will be
// reported as AmbiguousCall by the caller.
let required = params
.iter()
.filter(|p| p.name.name != "self" && p.default.is_none())
.count();
required == 0
} else if none_labeled && !args.is_empty() {
// Mode B: arity range check first, then match by first-argument type.
// Defaults broaden the acceptable arity to [required, total].
let non_self_count = params.iter().filter(|p| p.name.name != "self").count();
let required = params
.iter()
.filter(|p| p.name.name != "self" && p.default.is_none())
.count();
if args.len() < required || args.len() > non_self_count {
return false;
}
let first_arg_sem = args.first().map_or(SemType::Unknown, |(_, expr)| {
self.infer_type_sem(expr, file)
});
let first_param_sem = params
.iter()
.find(|p| p.name.name != "self")
.and_then(|p| p.ty.as_ref())
.map_or(SemType::Unknown, SemType::from_ast);
// Indeterminate either side means we can't tell — accept it
// (conservative). `is_unknown` returns true only for the bare
// `SemType::Unknown` variant; deeper compound types
// containing `Unknown` are caught by `is_indeterminate`.
first_arg_sem.is_indeterminate()
|| first_param_sem.is_indeterminate()
|| self.type_strings_compatible(&first_param_sem.display(), &first_arg_sem.display())
} else {
// Mixed labeled/unlabeled args have no defined match — overload
// resolution is all-labeled (mode A) or all-unlabeled (mode B).
false
}
}
/// Resolve a qualified function path like `math::compute` by traversing module symbol tables.
#[expect(clippy::indexing_slicing, reason = "parts length checked above")]
pub(super) fn resolve_qualified_function(&self, name: &str) -> bool {
let parts: Vec<&str> = name.splitn(2, "::").collect();
if parts.len() != 2 {
return false;
}
let (module_name, rest) = (parts[0], parts[1]);
if let Some(module_info) = self.symbols.modules.get(module_name) {
// Recurse into nested module paths
if rest.contains("::") {
let parts2: Vec<&str> = rest.splitn(2, "::").collect();
if parts2.len() == 2 {
let (sub_module, fn_name) = (parts2[0], parts2[1]);
if let Some(sub_mod) = module_info.symbols.modules.get(sub_module) {
return sub_mod.symbols.get_function(fn_name).is_some();
}
}
false
} else {
module_info.symbols.get_function(rest).is_some()
}
} else {
false
}
}
}