Better error for missing tuple pattern in args (#44150)
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sinkuu
parent
3ed8b69842
commit
8782d0fe78
3 changed files with 87 additions and 27 deletions
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@ -718,7 +718,9 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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return;
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}
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let expected_trait_ty = expected_trait_ref.self_ty();
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let found_span = expected_trait_ty.ty_to_def_id().and_then(|did| {
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let found_did = expected_trait_ty.ty_to_def_id();
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let found_span = found_did.and_then(|did| {
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self.tcx.hir.span_if_local(did)
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});
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@ -727,10 +729,11 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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ty::TyTuple(ref tys, _) => tys.len(),
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_ => 1,
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};
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let arg_ty_count =
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let (arg_tys, arg_ty_count) =
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match actual_trait_ref.skip_binder().substs.type_at(1).sty {
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ty::TyTuple(ref tys, _) => tys.len(),
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_ => 1,
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ty::TyTuple(ref tys, _) =>
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(tys.iter().map(|t| &t.sty).collect(), tys.len()),
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ref sty => (vec![sty], 1),
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};
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if self_ty_count == arg_ty_count {
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self.report_closure_arg_mismatch(span,
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@ -738,12 +741,45 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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expected_trait_ref,
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actual_trait_ref)
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} else {
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// Expected `|| { }`, found `|x, y| { }`
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// Expected `fn(x) -> ()`, found `|| { }`
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let arg_tuple = if arg_ty_count == 1 {
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arg_tys.first().and_then(|t| {
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if let &&ty::TyTuple(ref tuptys, _) = t {
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Some(tuptys.len())
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} else {
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None
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}
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})
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} else {
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None
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};
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// FIXME(#44150): Expand this to "N args expected bug a N-tuple found".
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// Type of the 1st expected argument is somehow provided as type of a
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// found one in that case.
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//
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// ```
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// [1i32, 2, 3].sort_by(|(a, b)| ..)
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// // ^^^^^^^^
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// // actual_trait_ref: std::ops::FnMut<(&i32, &i32)>
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// // expected_trait_ref: std::ops::FnMut<(&i32,)>
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// ```
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let closure_args_span = found_did.and_then(|did| self.tcx.hir.get_if_local(did))
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.and_then(|node| {
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if let hir::map::NodeExpr(
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&hir::Expr { node: hir::ExprClosure(_, _, _, span, _), .. }) = node
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{
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Some(span)
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} else {
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None
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}
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});
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self.report_arg_count_mismatch(
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span,
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found_span,
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closure_args_span.or(found_span),
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arg_ty_count,
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arg_tuple,
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self_ty_count,
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expected_trait_ty.is_closure()
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)
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@ -771,28 +807,42 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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span: Span,
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found_span: Option<Span>,
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expected: usize,
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expected_tuple: Option<usize>,
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found: usize,
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is_closure: bool)
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-> DiagnosticBuilder<'tcx>
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{
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let mut err = struct_span_err!(self.tcx.sess, span, E0593,
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"{} takes {} argument{} but {} argument{} {} required",
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if is_closure { "closure" } else { "function" },
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found,
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if found == 1 { "" } else { "s" },
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expected,
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if expected == 1 { "" } else { "s" },
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if expected == 1 { "is" } else { "are" });
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let kind = if is_closure { "closure" } else { "function" };
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let tuple_or_args = |tuple, args| if let Some(n) = tuple {
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format!("a {}-tuple", n)
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} else {
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format!(
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"{} argument{}",
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args,
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if args == 1 { "" } else { "s" }
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)
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};
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let found_str = tuple_or_args(None, found);
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let expected_str = tuple_or_args(expected_tuple, expected);
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let mut err = struct_span_err!(self.tcx.sess, span, E0593,
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"{} takes {} but {} {} required",
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kind,
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found_str,
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expected_str,
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if expected_tuple.is_some() || expected == 1 { "is" } else { "are" });
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err.span_label(
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span,
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format!("expected {} that takes {}", kind, expected_str)
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);
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err.span_label(span, format!("expected {} that takes {} argument{}",
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if is_closure { "closure" } else { "function" },
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expected,
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if expected == 1 { "" } else { "s" }));
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if let Some(span) = found_span {
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err.span_label(span, format!("takes {} argument{}",
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found,
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if found == 1 { "" } else { "s" }));
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err.span_label(span, format!("takes {}", found_str));
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}
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err
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}
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@ -16,4 +16,6 @@ fn main() {
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[1, 2, 3].sort_by(|tuple| panic!());
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[1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
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f(|| panic!());
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let _it = vec![1, 2, 3].into_iter().enumerate().map(|i, x| i);
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}
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@ -2,7 +2,7 @@ error[E0593]: closure takes 0 arguments but 2 arguments are required
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--> $DIR/closure-arg-count.rs:15:15
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15 | [1, 2, 3].sort_by(|| panic!());
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| ^^^^^^^ ----------- takes 0 arguments
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| ^^^^^^^ -- takes 0 arguments
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| |
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| expected closure that takes 2 arguments
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@ -10,7 +10,7 @@ error[E0593]: closure takes 1 argument but 2 arguments are required
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--> $DIR/closure-arg-count.rs:16:15
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16 | [1, 2, 3].sort_by(|tuple| panic!());
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| ^^^^^^^ ---------------- takes 1 argument
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| ^^^^^^^ ------- takes 1 argument
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| |
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| expected closure that takes 2 arguments
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@ -27,7 +27,7 @@ error[E0593]: closure takes 1 argument but 2 arguments are required
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--> $DIR/closure-arg-count.rs:17:15
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17 | [1, 2, 3].sort_by(|(tuple, tuple2)| panic!());
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| ^^^^^^^ -------------------------- takes 1 argument
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| ^^^^^^^ ----------------- takes 1 argument
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| |
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| expected closure that takes 2 arguments
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@ -35,11 +35,19 @@ error[E0593]: closure takes 0 arguments but 1 argument is required
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--> $DIR/closure-arg-count.rs:18:5
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18 | f(|| panic!());
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| ^ ----------- takes 0 arguments
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| ^ -- takes 0 arguments
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| |
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| expected closure that takes 1 argument
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= note: required by `f`
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error: aborting due to 5 previous errors
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error[E0593]: closure takes 2 arguments but a 2-tuple is required
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--> $DIR/closure-arg-count.rs:20:53
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20 | let _it = vec![1, 2, 3].into_iter().enumerate().map(|i, x| i);
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| ^^^ ------ takes 2 arguments
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| |
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| expected closure that takes a 2-tuple
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error: aborting due to 6 previous errors
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