mirror of
https://github.com/rust-lang/rust-analyzer
synced 2025-01-08 03:08:48 +00:00
1d5c4a77fb
Still far too much binder skipping going on; I find it hard to imagine this is all correct, but the tests pass.
963 lines
43 KiB
Rust
963 lines
43 KiB
Rust
//! Type inference for expressions.
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use std::iter::{repeat, repeat_with};
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use std::{mem, sync::Arc};
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use chalk_ir::{cast::Cast, Mutability, TyVariableKind};
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use hir_def::{
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expr::{Array, BinaryOp, Expr, ExprId, Literal, Statement, UnaryOp},
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path::{GenericArg, GenericArgs},
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resolver::resolver_for_expr,
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AssocContainerId, FieldId, Lookup,
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};
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use hir_expand::name::{name, Name};
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use stdx::always;
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use syntax::ast::RangeOp;
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use crate::{
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autoderef,
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lower::lower_to_chalk_mutability,
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method_resolution, op,
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primitive::{self, UintTy},
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to_assoc_type_id, to_chalk_trait_id,
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traits::{chalk::from_chalk, FnTrait, InEnvironment},
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utils::{generics, variant_data, Generics},
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AdtId, Binders, CallableDefId, DomainGoal, FnPointer, FnSig, Interner, Rawness, Scalar,
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Substitution, TraitRef, Ty, TyKind,
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};
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use super::{
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find_breakable, BindingMode, BreakableContext, Diverges, Expectation, InferenceContext,
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InferenceDiagnostic, TypeMismatch,
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};
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impl<'a> InferenceContext<'a> {
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pub(super) fn infer_expr(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
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let ty = self.infer_expr_inner(tgt_expr, expected);
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if ty.is_never() {
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// Any expression that produces a value of type `!` must have diverged
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self.diverges = Diverges::Always;
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}
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let could_unify = self.unify(&ty, &expected.ty);
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if !could_unify {
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self.result.type_mismatches.insert(
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tgt_expr,
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TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() },
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);
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}
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self.resolve_ty_as_possible(ty)
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}
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/// Infer type of expression with possibly implicit coerce to the expected type.
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/// Return the type after possible coercion.
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pub(super) fn infer_expr_coerce(&mut self, expr: ExprId, expected: &Expectation) -> Ty {
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let ty = self.infer_expr_inner(expr, &expected);
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let ty = if !self.coerce(&ty, &expected.coercion_target()) {
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self.result
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.type_mismatches
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.insert(expr, TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() });
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// Return actual type when type mismatch.
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// This is needed for diagnostic when return type mismatch.
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ty
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} else if expected.coercion_target().is_unknown() {
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ty
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} else {
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expected.ty.clone()
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};
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self.resolve_ty_as_possible(ty)
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}
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fn callable_sig_from_fn_trait(&mut self, ty: &Ty, num_args: usize) -> Option<(Vec<Ty>, Ty)> {
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let krate = self.resolver.krate()?;
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let fn_once_trait = FnTrait::FnOnce.get_id(self.db, krate)?;
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let output_assoc_type =
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self.db.trait_data(fn_once_trait).associated_type_by_name(&name![Output])?;
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let generic_params = generics(self.db.upcast(), fn_once_trait.into());
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if generic_params.len() != 2 {
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return None;
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}
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let mut param_builder = Substitution::builder(num_args);
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let mut arg_tys = vec![];
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for _ in 0..num_args {
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let arg = self.table.new_type_var();
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param_builder = param_builder.push(arg.clone());
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arg_tys.push(arg);
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}
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let parameters = param_builder.build();
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let arg_ty = TyKind::Tuple(num_args, parameters).intern(&Interner);
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let substs =
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Substitution::build_for_generics(&generic_params).push(ty.clone()).push(arg_ty).build();
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let trait_env = Arc::clone(&self.trait_env);
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let implements_fn_trait: DomainGoal =
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TraitRef { trait_id: to_chalk_trait_id(fn_once_trait), substitution: substs.clone() }
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.cast(&Interner);
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let goal = self.canonicalizer().canonicalize_obligation(InEnvironment {
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value: implements_fn_trait.clone(),
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environment: trait_env,
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});
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if self.db.trait_solve(krate, goal.value).is_some() {
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self.obligations.push(implements_fn_trait);
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let output_proj_ty = crate::ProjectionTy {
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associated_ty_id: to_assoc_type_id(output_assoc_type),
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substitution: substs,
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};
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let return_ty = self.normalize_projection_ty(output_proj_ty);
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Some((arg_tys, return_ty))
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} else {
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None
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}
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}
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pub(crate) fn callable_sig(&mut self, ty: &Ty, num_args: usize) -> Option<(Vec<Ty>, Ty)> {
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match ty.callable_sig(self.db) {
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Some(sig) => Some((sig.params().to_vec(), sig.ret().clone())),
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None => self.callable_sig_from_fn_trait(ty, num_args),
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}
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}
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fn infer_expr_inner(&mut self, tgt_expr: ExprId, expected: &Expectation) -> Ty {
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let body = Arc::clone(&self.body); // avoid borrow checker problem
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let ty = match &body[tgt_expr] {
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Expr::Missing => self.err_ty(),
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Expr::If { condition, then_branch, else_branch } => {
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// if let is desugared to match, so this is always simple if
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self.infer_expr(
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*condition,
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&Expectation::has_type(TyKind::Scalar(Scalar::Bool).intern(&Interner)),
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);
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let condition_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
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let mut both_arms_diverge = Diverges::Always;
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let then_ty = self.infer_expr_inner(*then_branch, &expected);
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both_arms_diverge &= mem::replace(&mut self.diverges, Diverges::Maybe);
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let else_ty = match else_branch {
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Some(else_branch) => self.infer_expr_inner(*else_branch, &expected),
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None => Ty::unit(),
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};
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both_arms_diverge &= self.diverges;
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self.diverges = condition_diverges | both_arms_diverge;
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self.coerce_merge_branch(&then_ty, &else_ty)
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}
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Expr::Block { statements, tail, label, id: _ } => {
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let old_resolver = mem::replace(
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&mut self.resolver,
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resolver_for_expr(self.db.upcast(), self.owner, tgt_expr),
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);
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let ty = match label {
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Some(_) => {
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let break_ty = self.table.new_type_var();
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self.breakables.push(BreakableContext {
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may_break: false,
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break_ty: break_ty.clone(),
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label: label.map(|label| self.body[label].name.clone()),
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});
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let ty =
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self.infer_block(statements, *tail, &Expectation::has_type(break_ty));
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let ctxt = self.breakables.pop().expect("breakable stack broken");
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if ctxt.may_break {
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ctxt.break_ty
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} else {
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ty
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}
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}
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None => self.infer_block(statements, *tail, expected),
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};
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self.resolver = old_resolver;
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ty
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}
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Expr::Unsafe { body } | Expr::Const { body } => self.infer_expr(*body, expected),
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Expr::TryBlock { body } => {
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let _inner = self.infer_expr(*body, expected);
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// FIXME should be std::result::Result<{inner}, _>
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self.err_ty()
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}
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Expr::Async { body } => {
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// Use the first type parameter as the output type of future.
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// existenail type AsyncBlockImplTrait<InnerType>: Future<Output = InnerType>
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let inner_ty = self.infer_expr(*body, &Expectation::none());
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let impl_trait_id = crate::ImplTraitId::AsyncBlockTypeImplTrait(self.owner, *body);
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let opaque_ty_id = self.db.intern_impl_trait_id(impl_trait_id).into();
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TyKind::OpaqueType(opaque_ty_id, Substitution::single(inner_ty)).intern(&Interner)
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}
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Expr::Loop { body, label } => {
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self.breakables.push(BreakableContext {
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may_break: false,
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break_ty: self.table.new_type_var(),
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label: label.map(|label| self.body[label].name.clone()),
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});
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self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
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let ctxt = self.breakables.pop().expect("breakable stack broken");
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if ctxt.may_break {
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self.diverges = Diverges::Maybe;
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}
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if ctxt.may_break {
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ctxt.break_ty
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} else {
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TyKind::Never.intern(&Interner)
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}
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}
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Expr::While { condition, body, label } => {
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self.breakables.push(BreakableContext {
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may_break: false,
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break_ty: self.err_ty(),
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label: label.map(|label| self.body[label].name.clone()),
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});
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// while let is desugared to a match loop, so this is always simple while
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self.infer_expr(
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*condition,
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&Expectation::has_type(TyKind::Scalar(Scalar::Bool).intern(&Interner)),
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);
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self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
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let _ctxt = self.breakables.pop().expect("breakable stack broken");
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// the body may not run, so it diverging doesn't mean we diverge
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self.diverges = Diverges::Maybe;
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Ty::unit()
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}
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Expr::For { iterable, body, pat, label } => {
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let iterable_ty = self.infer_expr(*iterable, &Expectation::none());
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self.breakables.push(BreakableContext {
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may_break: false,
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break_ty: self.err_ty(),
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label: label.map(|label| self.body[label].name.clone()),
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});
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let pat_ty =
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self.resolve_associated_type(iterable_ty, self.resolve_into_iter_item());
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self.infer_pat(*pat, &pat_ty, BindingMode::default());
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self.infer_expr(*body, &Expectation::has_type(Ty::unit()));
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let _ctxt = self.breakables.pop().expect("breakable stack broken");
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// the body may not run, so it diverging doesn't mean we diverge
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self.diverges = Diverges::Maybe;
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Ty::unit()
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}
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Expr::Lambda { body, args, ret_type, arg_types } => {
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assert_eq!(args.len(), arg_types.len());
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let mut sig_tys = Vec::new();
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// collect explicitly written argument types
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for arg_type in arg_types.iter() {
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let arg_ty = if let Some(type_ref) = arg_type {
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self.make_ty(type_ref)
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} else {
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self.table.new_type_var()
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};
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sig_tys.push(arg_ty);
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}
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// add return type
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let ret_ty = match ret_type {
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Some(type_ref) => self.make_ty(type_ref),
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None => self.table.new_type_var(),
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};
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sig_tys.push(ret_ty.clone());
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let sig_ty = TyKind::Function(FnPointer {
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num_args: sig_tys.len() - 1,
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sig: FnSig { abi: (), safety: chalk_ir::Safety::Safe, variadic: false },
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substs: Substitution(sig_tys.clone().into()),
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})
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.intern(&Interner);
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let closure_id = self.db.intern_closure((self.owner, tgt_expr)).into();
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let closure_ty =
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TyKind::Closure(closure_id, Substitution::single(sig_ty)).intern(&Interner);
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// Eagerly try to relate the closure type with the expected
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// type, otherwise we often won't have enough information to
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// infer the body.
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self.coerce(&closure_ty, &expected.ty);
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// Now go through the argument patterns
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for (arg_pat, arg_ty) in args.iter().zip(sig_tys) {
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let resolved = self.resolve_ty_as_possible(arg_ty);
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self.infer_pat(*arg_pat, &resolved, BindingMode::default());
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}
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let prev_diverges = mem::replace(&mut self.diverges, Diverges::Maybe);
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let prev_ret_ty = mem::replace(&mut self.return_ty, ret_ty.clone());
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self.infer_expr_coerce(*body, &Expectation::has_type(ret_ty));
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self.diverges = prev_diverges;
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self.return_ty = prev_ret_ty;
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closure_ty
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}
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Expr::Call { callee, args } => {
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let callee_ty = self.infer_expr(*callee, &Expectation::none());
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let canonicalized = self.canonicalizer().canonicalize_ty(callee_ty.clone());
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let mut derefs = autoderef(
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self.db,
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self.resolver.krate(),
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InEnvironment {
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value: canonicalized.value.clone(),
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environment: self.trait_env.clone(),
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},
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);
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let (param_tys, ret_ty): (Vec<Ty>, Ty) = derefs
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.find_map(|callee_deref_ty| {
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self.callable_sig(
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&canonicalized.decanonicalize_ty(callee_deref_ty.value),
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args.len(),
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)
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})
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.unwrap_or((Vec::new(), self.err_ty()));
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self.register_obligations_for_call(&callee_ty);
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self.check_call_arguments(args, ¶m_tys);
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self.normalize_associated_types_in(ret_ty)
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}
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Expr::MethodCall { receiver, args, method_name, generic_args } => self
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.infer_method_call(tgt_expr, *receiver, &args, &method_name, generic_args.as_ref()),
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Expr::Match { expr, arms } => {
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let input_ty = self.infer_expr(*expr, &Expectation::none());
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let mut result_ty = if arms.is_empty() {
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TyKind::Never.intern(&Interner)
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} else {
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self.table.new_type_var()
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};
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let matchee_diverges = self.diverges;
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let mut all_arms_diverge = Diverges::Always;
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for arm in arms {
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self.diverges = Diverges::Maybe;
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let _pat_ty = self.infer_pat(arm.pat, &input_ty, BindingMode::default());
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if let Some(guard_expr) = arm.guard {
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self.infer_expr(
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guard_expr,
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&Expectation::has_type(TyKind::Scalar(Scalar::Bool).intern(&Interner)),
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);
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}
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let arm_ty = self.infer_expr_inner(arm.expr, &expected);
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all_arms_diverge &= self.diverges;
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result_ty = self.coerce_merge_branch(&result_ty, &arm_ty);
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}
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self.diverges = matchee_diverges | all_arms_diverge;
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result_ty
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}
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Expr::Path(p) => {
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// FIXME this could be more efficient...
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let resolver = resolver_for_expr(self.db.upcast(), self.owner, tgt_expr);
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self.infer_path(&resolver, p, tgt_expr.into()).unwrap_or(self.err_ty())
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}
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Expr::Continue { .. } => TyKind::Never.intern(&Interner),
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Expr::Break { expr, label } => {
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let val_ty = if let Some(expr) = expr {
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self.infer_expr(*expr, &Expectation::none())
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} else {
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Ty::unit()
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};
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let last_ty =
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if let Some(ctxt) = find_breakable(&mut self.breakables, label.as_ref()) {
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ctxt.break_ty.clone()
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} else {
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self.err_ty()
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};
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let merged_type = self.coerce_merge_branch(&last_ty, &val_ty);
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if let Some(ctxt) = find_breakable(&mut self.breakables, label.as_ref()) {
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ctxt.break_ty = merged_type;
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ctxt.may_break = true;
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} else {
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self.push_diagnostic(InferenceDiagnostic::BreakOutsideOfLoop {
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expr: tgt_expr,
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});
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}
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TyKind::Never.intern(&Interner)
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}
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Expr::Return { expr } => {
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if let Some(expr) = expr {
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self.infer_expr_coerce(*expr, &Expectation::has_type(self.return_ty.clone()));
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} else {
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let unit = Ty::unit();
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self.coerce(&unit, &self.return_ty.clone());
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}
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TyKind::Never.intern(&Interner)
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}
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Expr::Yield { expr } => {
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// FIXME: track yield type for coercion
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if let Some(expr) = expr {
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self.infer_expr(*expr, &Expectation::none());
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}
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TyKind::Never.intern(&Interner)
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}
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Expr::RecordLit { path, fields, spread } => {
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let (ty, def_id) = self.resolve_variant(path.as_ref());
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if let Some(variant) = def_id {
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self.write_variant_resolution(tgt_expr.into(), variant);
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}
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self.unify(&ty, &expected.ty);
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let substs = ty.substs().cloned().unwrap_or_else(Substitution::empty);
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let field_types = def_id.map(|it| self.db.field_types(it)).unwrap_or_default();
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let variant_data = def_id.map(|it| variant_data(self.db.upcast(), it));
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for field in fields.iter() {
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let field_def =
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variant_data.as_ref().and_then(|it| match it.field(&field.name) {
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Some(local_id) => Some(FieldId { parent: def_id.unwrap(), local_id }),
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None => {
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self.push_diagnostic(InferenceDiagnostic::NoSuchField {
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expr: field.expr,
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});
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None
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}
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});
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if let Some(field_def) = field_def {
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self.result.record_field_resolutions.insert(field.expr, field_def);
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}
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let field_ty = field_def.map_or(self.err_ty(), |it| {
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field_types[it.local_id].clone().subst(&substs)
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});
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self.infer_expr_coerce(field.expr, &Expectation::has_type(field_ty));
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}
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if let Some(expr) = spread {
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self.infer_expr(*expr, &Expectation::has_type(ty.clone()));
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}
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ty
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}
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Expr::Field { expr, name } => {
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let receiver_ty = self.infer_expr_inner(*expr, &Expectation::none());
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let canonicalized = self.canonicalizer().canonicalize_ty(receiver_ty);
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let ty = autoderef::autoderef(
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self.db,
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self.resolver.krate(),
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InEnvironment {
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value: canonicalized.value.clone(),
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environment: self.trait_env.clone(),
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},
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)
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.find_map(|derefed_ty| {
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match canonicalized.decanonicalize_ty(derefed_ty.value).interned(&Interner) {
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TyKind::Tuple(_, substs) => {
|
|
name.as_tuple_index().and_then(|idx| substs.0.get(idx).cloned())
|
|
}
|
|
TyKind::Adt(AdtId(hir_def::AdtId::StructId(s)), parameters) => {
|
|
self.db.struct_data(*s).variant_data.field(name).map(|local_id| {
|
|
let field = FieldId { parent: (*s).into(), local_id };
|
|
self.write_field_resolution(tgt_expr, field);
|
|
self.db.field_types((*s).into())[field.local_id]
|
|
.clone()
|
|
.subst(¶meters)
|
|
})
|
|
}
|
|
TyKind::Adt(AdtId(hir_def::AdtId::UnionId(u)), parameters) => {
|
|
self.db.union_data(*u).variant_data.field(name).map(|local_id| {
|
|
let field = FieldId { parent: (*u).into(), local_id };
|
|
self.write_field_resolution(tgt_expr, field);
|
|
self.db.field_types((*u).into())[field.local_id]
|
|
.clone()
|
|
.subst(¶meters)
|
|
})
|
|
}
|
|
_ => None,
|
|
}
|
|
})
|
|
.unwrap_or(self.err_ty());
|
|
let ty = self.insert_type_vars(ty);
|
|
self.normalize_associated_types_in(ty)
|
|
}
|
|
Expr::Await { expr } => {
|
|
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
|
|
self.resolve_associated_type(inner_ty, self.resolve_future_future_output())
|
|
}
|
|
Expr::Try { expr } => {
|
|
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
|
|
self.resolve_associated_type(inner_ty, self.resolve_ops_try_ok())
|
|
}
|
|
Expr::Cast { expr, type_ref } => {
|
|
let _inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
|
|
let cast_ty = self.make_ty(type_ref);
|
|
// FIXME check the cast...
|
|
cast_ty
|
|
}
|
|
Expr::Ref { expr, rawness, mutability } => {
|
|
let mutability = lower_to_chalk_mutability(*mutability);
|
|
let expectation = if let Some((exp_inner, exp_rawness, exp_mutability)) =
|
|
&expected.ty.as_reference_or_ptr()
|
|
{
|
|
if *exp_mutability == Mutability::Mut && mutability == Mutability::Not {
|
|
// FIXME: throw type error - expected mut reference but found shared ref,
|
|
// which cannot be coerced
|
|
}
|
|
if *exp_rawness == Rawness::Ref && *rawness == Rawness::RawPtr {
|
|
// FIXME: throw type error - expected reference but found ptr,
|
|
// which cannot be coerced
|
|
}
|
|
Expectation::rvalue_hint(Ty::clone(exp_inner))
|
|
} else {
|
|
Expectation::none()
|
|
};
|
|
let inner_ty = self.infer_expr_inner(*expr, &expectation);
|
|
match rawness {
|
|
Rawness::RawPtr => TyKind::Raw(mutability, inner_ty),
|
|
Rawness::Ref => TyKind::Ref(mutability, inner_ty),
|
|
}
|
|
.intern(&Interner)
|
|
}
|
|
Expr::Box { expr } => {
|
|
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
|
|
if let Some(box_) = self.resolve_boxed_box() {
|
|
let mut sb =
|
|
Substitution::builder(generics(self.db.upcast(), box_.into()).len());
|
|
sb = sb.push(inner_ty);
|
|
match self.db.generic_defaults(box_.into()).as_ref() {
|
|
[_, alloc_ty, ..] if !alloc_ty.value.is_unknown() => {
|
|
sb = sb.push(alloc_ty.value.clone());
|
|
}
|
|
_ => (),
|
|
}
|
|
sb = sb.fill(repeat_with(|| self.table.new_type_var()));
|
|
Ty::adt_ty(box_, sb.build())
|
|
} else {
|
|
self.err_ty()
|
|
}
|
|
}
|
|
Expr::UnaryOp { expr, op } => {
|
|
let inner_ty = self.infer_expr_inner(*expr, &Expectation::none());
|
|
match op {
|
|
UnaryOp::Deref => match self.resolver.krate() {
|
|
Some(krate) => {
|
|
let canonicalized = self.canonicalizer().canonicalize_ty(inner_ty);
|
|
match autoderef::deref(
|
|
self.db,
|
|
krate,
|
|
InEnvironment {
|
|
value: &canonicalized.value,
|
|
environment: self.trait_env.clone(),
|
|
},
|
|
) {
|
|
Some(derefed_ty) => {
|
|
canonicalized.decanonicalize_ty(derefed_ty.value)
|
|
}
|
|
None => self.err_ty(),
|
|
}
|
|
}
|
|
None => self.err_ty(),
|
|
},
|
|
UnaryOp::Neg => {
|
|
match inner_ty.interned(&Interner) {
|
|
// Fast path for builtins
|
|
TyKind::Scalar(Scalar::Int(_))
|
|
| TyKind::Scalar(Scalar::Uint(_))
|
|
| TyKind::Scalar(Scalar::Float(_))
|
|
| TyKind::InferenceVar(_, TyVariableKind::Integer)
|
|
| TyKind::InferenceVar(_, TyVariableKind::Float) => inner_ty,
|
|
// Otherwise we resolve via the std::ops::Neg trait
|
|
_ => self
|
|
.resolve_associated_type(inner_ty, self.resolve_ops_neg_output()),
|
|
}
|
|
}
|
|
UnaryOp::Not => {
|
|
match inner_ty.interned(&Interner) {
|
|
// Fast path for builtins
|
|
TyKind::Scalar(Scalar::Bool)
|
|
| TyKind::Scalar(Scalar::Int(_))
|
|
| TyKind::Scalar(Scalar::Uint(_))
|
|
| TyKind::InferenceVar(_, TyVariableKind::Integer) => inner_ty,
|
|
// Otherwise we resolve via the std::ops::Not trait
|
|
_ => self
|
|
.resolve_associated_type(inner_ty, self.resolve_ops_not_output()),
|
|
}
|
|
}
|
|
}
|
|
}
|
|
Expr::BinaryOp { lhs, rhs, op } => match op {
|
|
Some(op) => {
|
|
let lhs_expectation = match op {
|
|
BinaryOp::LogicOp(..) => {
|
|
Expectation::has_type(TyKind::Scalar(Scalar::Bool).intern(&Interner))
|
|
}
|
|
_ => Expectation::none(),
|
|
};
|
|
let lhs_ty = self.infer_expr(*lhs, &lhs_expectation);
|
|
let rhs_expectation = op::binary_op_rhs_expectation(*op, lhs_ty.clone());
|
|
let rhs_ty = self.infer_expr(*rhs, &Expectation::has_type(rhs_expectation));
|
|
|
|
let ret = op::binary_op_return_ty(*op, lhs_ty.clone(), rhs_ty.clone());
|
|
|
|
if ret.is_unknown() {
|
|
cov_mark::hit!(infer_expr_inner_binary_operator_overload);
|
|
|
|
self.resolve_associated_type_with_params(
|
|
lhs_ty,
|
|
self.resolve_binary_op_output(op),
|
|
&[rhs_ty],
|
|
)
|
|
} else {
|
|
ret
|
|
}
|
|
}
|
|
_ => self.err_ty(),
|
|
},
|
|
Expr::Range { lhs, rhs, range_type } => {
|
|
let lhs_ty = lhs.map(|e| self.infer_expr_inner(e, &Expectation::none()));
|
|
let rhs_expect = lhs_ty
|
|
.as_ref()
|
|
.map_or_else(Expectation::none, |ty| Expectation::has_type(ty.clone()));
|
|
let rhs_ty = rhs.map(|e| self.infer_expr(e, &rhs_expect));
|
|
match (range_type, lhs_ty, rhs_ty) {
|
|
(RangeOp::Exclusive, None, None) => match self.resolve_range_full() {
|
|
Some(adt) => Ty::adt_ty(adt, Substitution::empty()),
|
|
None => self.err_ty(),
|
|
},
|
|
(RangeOp::Exclusive, None, Some(ty)) => match self.resolve_range_to() {
|
|
Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
|
|
None => self.err_ty(),
|
|
},
|
|
(RangeOp::Inclusive, None, Some(ty)) => {
|
|
match self.resolve_range_to_inclusive() {
|
|
Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
|
|
None => self.err_ty(),
|
|
}
|
|
}
|
|
(RangeOp::Exclusive, Some(_), Some(ty)) => match self.resolve_range() {
|
|
Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
|
|
None => self.err_ty(),
|
|
},
|
|
(RangeOp::Inclusive, Some(_), Some(ty)) => {
|
|
match self.resolve_range_inclusive() {
|
|
Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
|
|
None => self.err_ty(),
|
|
}
|
|
}
|
|
(RangeOp::Exclusive, Some(ty), None) => match self.resolve_range_from() {
|
|
Some(adt) => Ty::adt_ty(adt, Substitution::single(ty)),
|
|
None => self.err_ty(),
|
|
},
|
|
(RangeOp::Inclusive, _, None) => self.err_ty(),
|
|
}
|
|
}
|
|
Expr::Index { base, index } => {
|
|
let base_ty = self.infer_expr_inner(*base, &Expectation::none());
|
|
let index_ty = self.infer_expr(*index, &Expectation::none());
|
|
|
|
if let (Some(index_trait), Some(krate)) =
|
|
(self.resolve_ops_index(), self.resolver.krate())
|
|
{
|
|
let canonicalized = self.canonicalizer().canonicalize_ty(base_ty);
|
|
let self_ty = method_resolution::resolve_indexing_op(
|
|
self.db,
|
|
&canonicalized.value,
|
|
self.trait_env.clone(),
|
|
krate,
|
|
index_trait,
|
|
);
|
|
let self_ty =
|
|
self_ty.map_or(self.err_ty(), |t| canonicalized.decanonicalize_ty(t.value));
|
|
self.resolve_associated_type_with_params(
|
|
self_ty,
|
|
self.resolve_ops_index_output(),
|
|
&[index_ty],
|
|
)
|
|
} else {
|
|
self.err_ty()
|
|
}
|
|
}
|
|
Expr::Tuple { exprs } => {
|
|
let mut tys = match expected.ty.interned(&Interner) {
|
|
TyKind::Tuple(_, substs) => substs
|
|
.iter()
|
|
.cloned()
|
|
.chain(repeat_with(|| self.table.new_type_var()))
|
|
.take(exprs.len())
|
|
.collect::<Vec<_>>(),
|
|
_ => (0..exprs.len()).map(|_| self.table.new_type_var()).collect(),
|
|
};
|
|
|
|
for (expr, ty) in exprs.iter().zip(tys.iter_mut()) {
|
|
self.infer_expr_coerce(*expr, &Expectation::has_type(ty.clone()));
|
|
}
|
|
|
|
TyKind::Tuple(tys.len(), Substitution(tys.into())).intern(&Interner)
|
|
}
|
|
Expr::Array(array) => {
|
|
let elem_ty = match expected.ty.interned(&Interner) {
|
|
TyKind::Array(st) | TyKind::Slice(st) => st.clone(),
|
|
_ => self.table.new_type_var(),
|
|
};
|
|
|
|
match array {
|
|
Array::ElementList(items) => {
|
|
for expr in items.iter() {
|
|
self.infer_expr_coerce(*expr, &Expectation::has_type(elem_ty.clone()));
|
|
}
|
|
}
|
|
Array::Repeat { initializer, repeat } => {
|
|
self.infer_expr_coerce(
|
|
*initializer,
|
|
&Expectation::has_type(elem_ty.clone()),
|
|
);
|
|
self.infer_expr(
|
|
*repeat,
|
|
&Expectation::has_type(
|
|
TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(&Interner),
|
|
),
|
|
);
|
|
}
|
|
}
|
|
|
|
TyKind::Array(elem_ty).intern(&Interner)
|
|
}
|
|
Expr::Literal(lit) => match lit {
|
|
Literal::Bool(..) => TyKind::Scalar(Scalar::Bool).intern(&Interner),
|
|
Literal::String(..) => {
|
|
TyKind::Ref(Mutability::Not, TyKind::Str.intern(&Interner)).intern(&Interner)
|
|
}
|
|
Literal::ByteString(..) => {
|
|
let byte_type = TyKind::Scalar(Scalar::Uint(UintTy::U8)).intern(&Interner);
|
|
let array_type = TyKind::Array(byte_type).intern(&Interner);
|
|
TyKind::Ref(Mutability::Not, array_type).intern(&Interner)
|
|
}
|
|
Literal::Char(..) => TyKind::Scalar(Scalar::Char).intern(&Interner),
|
|
Literal::Int(_v, ty) => match ty {
|
|
Some(int_ty) => {
|
|
TyKind::Scalar(Scalar::Int(primitive::int_ty_from_builtin(*int_ty)))
|
|
.intern(&Interner)
|
|
}
|
|
None => self.table.new_integer_var(),
|
|
},
|
|
Literal::Uint(_v, ty) => match ty {
|
|
Some(int_ty) => {
|
|
TyKind::Scalar(Scalar::Uint(primitive::uint_ty_from_builtin(*int_ty)))
|
|
.intern(&Interner)
|
|
}
|
|
None => self.table.new_integer_var(),
|
|
},
|
|
Literal::Float(_v, ty) => match ty {
|
|
Some(float_ty) => {
|
|
TyKind::Scalar(Scalar::Float(primitive::float_ty_from_builtin(*float_ty)))
|
|
.intern(&Interner)
|
|
}
|
|
None => self.table.new_float_var(),
|
|
},
|
|
},
|
|
};
|
|
// use a new type variable if we got unknown here
|
|
let ty = self.insert_type_vars_shallow(ty);
|
|
let ty = self.resolve_ty_as_possible(ty);
|
|
self.write_expr_ty(tgt_expr, ty.clone());
|
|
ty
|
|
}
|
|
|
|
fn infer_block(
|
|
&mut self,
|
|
statements: &[Statement],
|
|
tail: Option<ExprId>,
|
|
expected: &Expectation,
|
|
) -> Ty {
|
|
for stmt in statements {
|
|
match stmt {
|
|
Statement::Let { pat, type_ref, initializer } => {
|
|
let decl_ty =
|
|
type_ref.as_ref().map(|tr| self.make_ty(tr)).unwrap_or(self.err_ty());
|
|
|
|
// Always use the declared type when specified
|
|
let mut ty = decl_ty.clone();
|
|
|
|
if let Some(expr) = initializer {
|
|
let actual_ty =
|
|
self.infer_expr_coerce(*expr, &Expectation::has_type(decl_ty.clone()));
|
|
if decl_ty.is_unknown() {
|
|
ty = actual_ty;
|
|
}
|
|
}
|
|
|
|
let ty = self.resolve_ty_as_possible(ty);
|
|
self.infer_pat(*pat, &ty, BindingMode::default());
|
|
}
|
|
Statement::Expr(expr) => {
|
|
self.infer_expr(*expr, &Expectation::none());
|
|
}
|
|
}
|
|
}
|
|
|
|
let ty = if let Some(expr) = tail {
|
|
self.infer_expr_coerce(expr, expected)
|
|
} else {
|
|
// Citing rustc: if there is no explicit tail expression,
|
|
// that is typically equivalent to a tail expression
|
|
// of `()` -- except if the block diverges. In that
|
|
// case, there is no value supplied from the tail
|
|
// expression (assuming there are no other breaks,
|
|
// this implies that the type of the block will be
|
|
// `!`).
|
|
if self.diverges.is_always() {
|
|
// we don't even make an attempt at coercion
|
|
self.table.new_maybe_never_var()
|
|
} else {
|
|
self.coerce(&Ty::unit(), &expected.coercion_target());
|
|
Ty::unit()
|
|
}
|
|
};
|
|
ty
|
|
}
|
|
|
|
fn infer_method_call(
|
|
&mut self,
|
|
tgt_expr: ExprId,
|
|
receiver: ExprId,
|
|
args: &[ExprId],
|
|
method_name: &Name,
|
|
generic_args: Option<&GenericArgs>,
|
|
) -> Ty {
|
|
let receiver_ty = self.infer_expr(receiver, &Expectation::none());
|
|
let canonicalized_receiver = self.canonicalizer().canonicalize_ty(receiver_ty.clone());
|
|
|
|
let traits_in_scope = self.resolver.traits_in_scope(self.db.upcast());
|
|
|
|
let resolved = self.resolver.krate().and_then(|krate| {
|
|
method_resolution::lookup_method(
|
|
&canonicalized_receiver.value,
|
|
self.db,
|
|
self.trait_env.clone(),
|
|
krate,
|
|
&traits_in_scope,
|
|
method_name,
|
|
)
|
|
});
|
|
let (derefed_receiver_ty, method_ty, def_generics) = match resolved {
|
|
Some((ty, func)) => {
|
|
let ty = canonicalized_receiver.decanonicalize_ty(ty);
|
|
self.write_method_resolution(tgt_expr, func);
|
|
(ty, self.db.value_ty(func.into()), Some(generics(self.db.upcast(), func.into())))
|
|
}
|
|
None => (receiver_ty, Binders::new(0, self.err_ty()), None),
|
|
};
|
|
let substs = self.substs_for_method_call(def_generics, generic_args, &derefed_receiver_ty);
|
|
let method_ty = method_ty.subst(&substs);
|
|
let method_ty = self.insert_type_vars(method_ty);
|
|
self.register_obligations_for_call(&method_ty);
|
|
let (expected_receiver_ty, param_tys, ret_ty) = match method_ty.callable_sig(self.db) {
|
|
Some(sig) => {
|
|
if !sig.params().is_empty() {
|
|
(sig.params()[0].clone(), sig.params()[1..].to_vec(), sig.ret().clone())
|
|
} else {
|
|
(self.err_ty(), Vec::new(), sig.ret().clone())
|
|
}
|
|
}
|
|
None => (self.err_ty(), Vec::new(), self.err_ty()),
|
|
};
|
|
// Apply autoref so the below unification works correctly
|
|
// FIXME: return correct autorefs from lookup_method
|
|
let actual_receiver_ty = match expected_receiver_ty.as_reference() {
|
|
Some((_, mutability)) => TyKind::Ref(mutability, derefed_receiver_ty).intern(&Interner),
|
|
_ => derefed_receiver_ty,
|
|
};
|
|
self.unify(&expected_receiver_ty, &actual_receiver_ty);
|
|
|
|
self.check_call_arguments(args, ¶m_tys);
|
|
self.normalize_associated_types_in(ret_ty)
|
|
}
|
|
|
|
fn check_call_arguments(&mut self, args: &[ExprId], param_tys: &[Ty]) {
|
|
// Quoting https://github.com/rust-lang/rust/blob/6ef275e6c3cb1384ec78128eceeb4963ff788dca/src/librustc_typeck/check/mod.rs#L3325 --
|
|
// We do this in a pretty awful way: first we type-check any arguments
|
|
// that are not closures, then we type-check the closures. This is so
|
|
// that we have more information about the types of arguments when we
|
|
// type-check the functions. This isn't really the right way to do this.
|
|
for &check_closures in &[false, true] {
|
|
let param_iter = param_tys.iter().cloned().chain(repeat(self.err_ty()));
|
|
for (&arg, param_ty) in args.iter().zip(param_iter) {
|
|
let is_closure = matches!(&self.body[arg], Expr::Lambda { .. });
|
|
if is_closure != check_closures {
|
|
continue;
|
|
}
|
|
|
|
let param_ty = self.normalize_associated_types_in(param_ty);
|
|
self.infer_expr_coerce(arg, &Expectation::has_type(param_ty.clone()));
|
|
}
|
|
}
|
|
}
|
|
|
|
fn substs_for_method_call(
|
|
&mut self,
|
|
def_generics: Option<Generics>,
|
|
generic_args: Option<&GenericArgs>,
|
|
receiver_ty: &Ty,
|
|
) -> Substitution {
|
|
let (parent_params, self_params, type_params, impl_trait_params) =
|
|
def_generics.as_ref().map_or((0, 0, 0, 0), |g| g.provenance_split());
|
|
assert_eq!(self_params, 0); // method shouldn't have another Self param
|
|
let total_len = parent_params + type_params + impl_trait_params;
|
|
let mut substs = Vec::with_capacity(total_len);
|
|
// Parent arguments are unknown, except for the receiver type
|
|
if let Some(parent_generics) = def_generics.as_ref().map(|p| p.iter_parent()) {
|
|
for (_id, param) in parent_generics {
|
|
if param.provenance == hir_def::generics::TypeParamProvenance::TraitSelf {
|
|
substs.push(receiver_ty.clone());
|
|
} else {
|
|
substs.push(self.err_ty());
|
|
}
|
|
}
|
|
}
|
|
// handle provided type arguments
|
|
if let Some(generic_args) = generic_args {
|
|
// if args are provided, it should be all of them, but we can't rely on that
|
|
for arg in generic_args
|
|
.args
|
|
.iter()
|
|
.filter(|arg| matches!(arg, GenericArg::Type(_)))
|
|
.take(type_params)
|
|
{
|
|
match arg {
|
|
GenericArg::Type(type_ref) => {
|
|
let ty = self.make_ty(type_ref);
|
|
substs.push(ty);
|
|
}
|
|
GenericArg::Lifetime(_) => {}
|
|
}
|
|
}
|
|
};
|
|
let supplied_params = substs.len();
|
|
for _ in supplied_params..total_len {
|
|
substs.push(self.err_ty());
|
|
}
|
|
assert_eq!(substs.len(), total_len);
|
|
Substitution(substs.into())
|
|
}
|
|
|
|
fn register_obligations_for_call(&mut self, callable_ty: &Ty) {
|
|
if let TyKind::FnDef(fn_def, parameters) = callable_ty.interned(&Interner) {
|
|
let def: CallableDefId = from_chalk(self.db, *fn_def);
|
|
let generic_predicates = self.db.generic_predicates(def.into());
|
|
for predicate in generic_predicates.iter() {
|
|
let (predicate, binders) =
|
|
predicate.clone().subst(parameters).into_value_and_skipped_binders();
|
|
always!(binders == 0); // quantified where clauses not yet handled
|
|
self.obligations.push(predicate.cast(&Interner));
|
|
}
|
|
// add obligation for trait implementation, if this is a trait method
|
|
match def {
|
|
CallableDefId::FunctionId(f) => {
|
|
if let AssocContainerId::TraitId(trait_) = f.lookup(self.db.upcast()).container
|
|
{
|
|
// construct a TraitRef
|
|
let substs =
|
|
parameters.prefix(generics(self.db.upcast(), trait_.into()).len());
|
|
self.obligations.push(
|
|
TraitRef { trait_id: to_chalk_trait_id(trait_), substitution: substs }
|
|
.cast(&Interner),
|
|
);
|
|
}
|
|
}
|
|
CallableDefId::StructId(_) | CallableDefId::EnumVariantId(_) => {}
|
|
}
|
|
}
|
|
}
|
|
}
|