bjoernager/rust
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Simplify for loop desugar

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This commit is contained in:
Cameron Steffen 2021-10-25 23:33:12 -05:00
parent 3bfde2f1f4
commit 9c83f8c4d1
26 changed files with 181 additions and 256 deletions
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24
compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
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@ -5,13 +5,12 @@ use rustc_hir as hir;
use rustc_hir::def::{DefKind, Namespace};
use rustc_hir::def_id::DefId;
use rustc_hir::intravisit::{self, NestedVisitorMap, Visitor};
use rustc_hir::{Body, Expr, ExprKind, FnRetTy, HirId, Local, Pat};
use rustc_hir::{Body, Expr, ExprKind, FnRetTy, HirId, Local, MatchSource, Pat};
use rustc_middle::hir::map::Map;
use rustc_middle::infer::unify_key::ConstVariableOriginKind;
use rustc_middle::ty::print::Print;
use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
use rustc_middle::ty::{self, DefIdTree, InferConst, Ty, TyCtxt};
use rustc_span::source_map::DesugaringKind;
use rustc_span::symbol::kw;
use rustc_span::Span;
use std::borrow::Cow;
@ -26,6 +25,7 @@ struct FindHirNodeVisitor<'a, 'tcx> {
found_closure: Option<&'tcx Expr<'tcx>>,
found_method_call: Option<&'tcx Expr<'tcx>>,
found_exact_method_call: Option<&'tcx Expr<'tcx>>,
found_for_loop_iter: Option<&'tcx Expr<'tcx>>,
found_use_diagnostic: Option<UseDiagnostic<'tcx>>,
}
@ -41,6 +41,7 @@ impl<'a, 'tcx> FindHirNodeVisitor<'a, 'tcx> {
found_closure: None,
found_method_call: None,
found_exact_method_call: None,
found_for_loop_iter: None,
found_use_diagnostic: None,
}
}
@ -111,6 +112,15 @@ impl<'a, 'tcx> Visitor<'tcx> for FindHirNodeVisitor<'a, 'tcx> {
}
fn visit_expr(&mut self, expr: &'tcx Expr<'tcx>) {
if let ExprKind::Match(scrutinee, [_, arm], MatchSource::ForLoopDesugar) = expr.kind {
if let Some(pat) = arm.pat.for_loop_some() {
if let Some(ty) = self.node_ty_contains_target(pat.hir_id) {
self.found_for_loop_iter = Some(scrutinee);
self.found_node_ty = Some(ty);
return;
}
}
}
if let ExprKind::MethodCall(_, call_span, exprs, _) = expr.kind {
if call_span == self.target_span
&& Some(self.target)
@ -643,10 +653,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
let msg = if let Some(simple_ident) = pattern.simple_ident() {
match pattern.span.desugaring_kind() {
None => format!("consider giving `{}` {}", simple_ident, suffix),
Some(DesugaringKind::ForLoop(_)) => {
"the element type for this iterator is not specified".to_string()
}
_ => format!("this needs {}", suffix),
Some(_) => format!("this needs {}", suffix),
}
} else {
format!("consider giving this pattern {}", suffix)
@ -719,6 +726,11 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
// = note: type must be known at this point
self.annotate_method_call(segment, e, &mut err);
}
} else if let Some(scrutinee) = local_visitor.found_for_loop_iter {
err.span_label(
scrutinee.span,
"the element type for this iterator is not specified".to_string(),
);
}
// Instead of the following:
// error[E0282]: type annotations needed