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Keep track of the start of the argument block of a closure

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This commit is contained in:
Sarthak Singh 2022-11-09 20:39:28 +05:30
parent 872631d0f0
commit 8f705e2425
15 changed files with 53 additions and 29 deletions
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35
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
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@ -70,7 +70,7 @@ pub trait InferCtxtExt<'tcx> {
/// returns a span and `ArgKind` information that describes the
/// arguments it expects. This can be supplied to
/// `report_arg_count_mismatch`.
fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Vec<ArgKind>)>;
fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Option<Span>, Vec<ArgKind>)>;
/// Reports an error when the number of arguments needed by a
/// trait match doesn't match the number that the expression
@ -82,6 +82,7 @@ pub trait InferCtxtExt<'tcx> {
expected_args: Vec<ArgKind>,
found_args: Vec<ArgKind>,
is_closure: bool,
closure_pipe_span: Option<Span>,
) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
/// Checks if the type implements one of `Fn`, `FnMut`, or `FnOnce`
@ -134,15 +135,16 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
/// returns a span and `ArgKind` information that describes the
/// arguments it expects. This can be supplied to
/// `report_arg_count_mismatch`.
fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Vec<ArgKind>)> {
fn get_fn_like_arguments(&self, node: Node<'_>) -> Option<(Span, Option<Span>, Vec<ArgKind>)> {
let sm = self.tcx.sess.source_map();
let hir = self.tcx.hir();
Some(match node {
Node::Expr(&hir::Expr {
kind: hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, .. }),
kind: hir::ExprKind::Closure(&hir::Closure { body, fn_decl_span, fn_arg_span, .. }),
..
}) => (
fn_decl_span,
fn_arg_span,
hir.body(body)
.params
.iter()
@ -173,6 +175,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
kind: hir::TraitItemKind::Fn(ref sig, _), ..
}) => (
sig.span,
None,
sig.decl
.inputs
.iter()
@ -187,7 +190,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
),
Node::Ctor(ref variant_data) => {
let span = variant_data.ctor_hir_id().map_or(DUMMY_SP, |id| hir.span(id));
(span, vec![ArgKind::empty(); variant_data.fields().len()])
(span, None, vec![ArgKind::empty(); variant_data.fields().len()])
}
_ => panic!("non-FnLike node found: {:?}", node),
})
@ -203,6 +206,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
expected_args: Vec<ArgKind>,
found_args: Vec<ArgKind>,
is_closure: bool,
closure_arg_span: Option<Span>,
) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
let kind = if is_closure { "closure" } else { "function" };
@ -240,24 +244,13 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
if let Some(found_span) = found_span {
err.span_label(found_span, format!("takes {}", found_str));
// move |_| { ... }
// ^^^^^^^^-- def_span
//
// move |_| { ... }
// ^^^^^-- prefix
let prefix_span = self.tcx.sess.source_map().span_until_non_whitespace(found_span);
// move |_| { ... }
// ^^^-- pipe_span
let pipe_span =
if let Some(span) = found_span.trim_start(prefix_span) { span } else { found_span };
// Suggest to take and ignore the arguments with expected_args_length `_`s if
// found arguments is empty (assume the user just wants to ignore args in this case).
// For example, if `expected_args_length` is 2, suggest `|_, _|`.
if found_args.is_empty() && is_closure {
let underscores = vec!["_"; expected_args.len()].join(", ");
err.span_suggestion_verbose(
pipe_span,
closure_arg_span.unwrap_or(found_span),
&format!(
"consider changing the closure to take and ignore the expected argument{}",
pluralize!(expected_args.len())
@ -1251,13 +1244,14 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
obligation.cause.code(),
)
} else {
let (closure_span, found) = found_did
let (closure_span, closure_arg_span, found) = found_did
.and_then(|did| {
let node = self.tcx.hir().get_if_local(did)?;
let (found_span, found) = self.get_fn_like_arguments(node)?;
Some((Some(found_span), found))
let (found_span, closure_arg_span, found) =
self.get_fn_like_arguments(node)?;
Some((Some(found_span), closure_arg_span, found))
})
.unwrap_or((found_span, found));
.unwrap_or((found_span, None, found));
self.report_arg_count_mismatch(
span,
@ -1265,6 +1259,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
expected,
found,
found_trait_ty.is_closure(),
closure_arg_span,
)
}
}