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Rollup merge of #123924 - compiler-errors:tuple-sugg, r=estebank

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Fix various bugs in `ty_kind_suggestion`

Consolidates two implementations of `ty_kind_suggestion`
Fixes some misuse of the empty param-env
Fixes a problem where we suggested `(42)` instead of `(42,)` for tuple suggestions
Suggest a value when `return;`, making it consistent with `break;`
Fixes #123906
This commit is contained in:
Michael Goulet 2024-04-15 15:18:06 -04:00 • committed by GitHub
commit 20a5fb3b4a
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12 changed files with 139 additions and 130 deletions
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1
compiler/rustc_trait_selection/src/lib.rs
View file

@ -22,6 +22,7 @@
#![feature(box_patterns)]
#![feature(control_flow_enum)]
#![feature(extract_if)]
#![feature(if_let_guard)]
#![feature(let_chains)]
#![feature(option_take_if)]
#![feature(never_type)]

55
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file

@ -4540,6 +4540,61 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
Applicability::MachineApplicable,
);
}
fn ty_kind_suggestion(&self, param_env: ty::ParamEnv<'tcx>, ty: Ty<'tcx>) -> Option<String> {
let tcx = self.infcx.tcx;
let implements_default = |ty| {
let Some(default_trait) = tcx.get_diagnostic_item(sym::Default) else {
return false;
};
self.type_implements_trait(default_trait, [ty], param_env).must_apply_modulo_regions()
};
Some(match ty.kind() {
ty::Never | ty::Error(_) => return None,
ty::Bool => "false".to_string(),
ty::Char => "\'x\'".to_string(),
ty::Int(_) | ty::Uint(_) => "42".into(),
ty::Float(_) => "3.14159".into(),
ty::Slice(_) => "[]".to_string(),
ty::Adt(def, _) if Some(def.did()) == tcx.get_diagnostic_item(sym::Vec) => {
"vec![]".to_string()
}
ty::Adt(def, _) if Some(def.did()) == tcx.get_diagnostic_item(sym::String) => {
"String::new()".to_string()
}
ty::Adt(def, args) if def.is_box() => {
format!("Box::new({})", self.ty_kind_suggestion(param_env, args[0].expect_ty())?)
}
ty::Adt(def, _) if Some(def.did()) == tcx.get_diagnostic_item(sym::Option) => {
"None".to_string()
}
ty::Adt(def, args) if Some(def.did()) == tcx.get_diagnostic_item(sym::Result) => {
format!("Ok({})", self.ty_kind_suggestion(param_env, args[0].expect_ty())?)
}
ty::Adt(_, _) if implements_default(ty) => "Default::default()".to_string(),
ty::Ref(_, ty, mutability) => {
if let (ty::Str, hir::Mutability::Not) = (ty.kind(), mutability) {
"\"\"".to_string()
} else {
let ty = self.ty_kind_suggestion(param_env, *ty)?;
format!("&{}{ty}", mutability.prefix_str())
}
}
ty::Array(ty, len) if let Some(len) = len.try_eval_target_usize(tcx, param_env) => {
format!("[{}; {}]", self.ty_kind_suggestion(param_env, *ty)?, len)
}
ty::Tuple(tys) => format!(
"({}{})",
tys.iter()
.map(|ty| self.ty_kind_suggestion(param_env, ty))
.collect::<Option<Vec<String>>>()?
.join(", "),
if tys.len() == 1 { "," } else { "" }
),
_ => "value".to_string(),
})
}
}
/// Add a hint to add a missing borrow or remove an unnecessary one.