bjoernager/rust
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use param instead of ty

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Signed-off-by: Alex Chi <iskyzh@gmail.com>
This commit is contained in:
Alex Chi 2023-03-17 23:21:01 -04:00
parent 54c11a688f
commit 173b8567ee
4 changed files with 63 additions and 75 deletions
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22
compiler/rustc_infer/src/infer/error_reporting/suggest.rs
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@ -547,7 +547,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
diag: &mut Diagnostic,
) {
// 0. Extract fn_decl from hir
let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(hir::Closure { fn_decl, .. }), .. }) = hir else { return; };
let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Closure(hir::Closure { body, fn_decl, .. }), .. }) = hir else { return; };
let hir::Body { params, .. } = self.tcx.hir().body(*body);
// 1. Get the substs of the closure.
// 2. Assume exp_found is FnOnce / FnMut / Fn, we can extract function parameters from [1].
@ -565,7 +566,10 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
let mut is_first = true;
let mut has_suggestion = false;
for ((expected, found), arg_hir) in expected.iter().zip(found.iter()).zip(fn_decl.inputs.iter()) {
for (((expected, found), param_hir), arg_hir) in expected.iter()
.zip(found.iter())
.zip(params.iter())
.zip(fn_decl.inputs.iter()) {
if is_first {
is_first = false;
} else {
@ -579,11 +583,19 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
let hir::TyKind::Infer = arg_hir.kind {
// If the expected region is late bound, the found region is not, and users are asking compiler
// to infer the type, we can suggest adding `: &_`.
let Ok(arg) = self.tcx.sess.source_map().span_to_snippet(arg_hir.span) else { return; };
suggestion += &format!("{}: &_", arg);
if param_hir.pat.span == param_hir.ty_span {
// for `|x|`, `|_|`, `|x: impl Foo|`
let Ok(pat) = self.tcx.sess.source_map().span_to_snippet(param_hir.pat.span) else { return; };
suggestion += &format!("{}: &_", pat);
} else {
// for `|x: ty|`, `|_: ty|`
let Ok(pat) = self.tcx.sess.source_map().span_to_snippet(param_hir.pat.span) else { return; };
let Ok(ty) = self.tcx.sess.source_map().span_to_snippet(param_hir.ty_span) else { return; };
suggestion += &format!("{}: &{}", pat, ty);
}
has_suggestion = true;
} else {
let Ok(arg) = self.tcx.sess.source_map().span_to_snippet(arg_hir.span) else { return; };
let Ok(arg) = self.tcx.sess.source_map().span_to_snippet(param_hir.span) else { return; };
// Otherwise, keep it as-is.
suggestion += &arg;
}