bjoernager/rust
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Suggest replace parentheses with angle brackets

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This commit is contained in:
EdwinRy 2022-06-02 18:22:25 +01:00
parent 9598b4b594
commit cd03fe18d8
3 changed files with 73 additions and 9 deletions
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46
compiler/rustc_ast_lowering/src/lib.rs
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@ -46,7 +46,7 @@ use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::sorted_map::SortedMap;
use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
use rustc_data_structures::sync::Lrc;
use rustc_errors::struct_span_err;
use rustc_errors::{struct_span_err, Applicability};
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Namespace, PartialRes, PerNS, Res};
use rustc_hir::def_id::{DefId, DefPathHash, LocalDefId, CRATE_DEF_ID};
@ -901,7 +901,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
mut itctx: ImplTraitContext<'_, 'hir>,
) -> hir::TypeBinding<'hir> {
debug!("lower_assoc_ty_constraint(constraint={:?}, itctx={:?})", constraint, itctx);
// lower generic arguments of identifier in constraint
let gen_args = if let Some(ref gen_args) = constraint.gen_args {
let gen_args_ctor = match gen_args {
@ -914,12 +913,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
.0
}
GenericArgs::Parenthesized(ref data) => {
let mut err = self.sess.struct_span_err(
gen_args.span(),
"parenthesized generic arguments cannot be used in associated type constraints"
);
// FIXME: try to write a suggestion here
err.emit();
self.assoc_ty_contraint_param_error_emit(data);
self.lower_angle_bracketed_parameter_data(
&data.as_angle_bracketed_args(),
ParamMode::Explicit,
@ -1033,6 +1027,42 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
fn assoc_ty_contraint_param_error_emit(&self, data: &ParenthesizedArgs) -> () {
let mut err = self.sess.struct_span_err(
data.span,
"parenthesized generic arguments cannot be used in associated type constraints",
);
// Suggest removing empty parentheses: "Trait()" -> "Trait"
if data.inputs.is_empty() {
let parentheses_span =
data.inputs_span.shrink_to_lo().to(data.inputs_span.shrink_to_hi());
err.multipart_suggestion(
"remove these parentheses",
vec![(parentheses_span, String::new())],
Applicability::MaybeIncorrect,
);
}
// Suggest replacing parentheses with angle brackets `Trait(params...)` to `Trait<params...>`
else {
// Start of parameters to the 1st argument
let open_param = data.inputs_span.shrink_to_lo().to(data
.inputs
.first()
.unwrap()
.span
.shrink_to_lo());
// End of last argument to end of parameters
let close_param =
data.inputs.last().unwrap().span.shrink_to_hi().to(data.inputs_span.shrink_to_hi());
err.multipart_suggestion(
&format!("use angle brackets instead",),
vec![(open_param, String::from("<")), (close_param, String::from(">"))],
Applicability::MaybeIncorrect,
);
}
err.emit();
}
fn lower_generic_arg(
&mut self,
arg: &ast::GenericArg,