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More robust as_ref/as_deref suggestions

This commit is contained in:
Michael Goulet 2023-05-30 18:47:50 +00:00
parent 522ae84e03
commit af54d584b2
12 changed files with 208 additions and 153 deletions
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2
compiler/rustc_hir_typeck/messages.ftl
View File

@ -25,6 +25,8 @@ hir_typeck_const_select_must_be_fn = this argument must be a function item
hir_typeck_convert_to_str = try converting the passed type into a `&str`
hir_typeck_convert_using_method = try using `{$sugg}` to convert `{$found}` to `{$expected}`
hir_typeck_ctor_is_private = tuple struct constructor `{$def}` is private
hir_typeck_expected_default_return_type = expected `()` because of default return type

15
compiler/rustc_hir_typeck/src/errors.rs
View File

@ -327,3 +327,18 @@ pub struct CtorIsPrivate {
pub span: Span,
pub def: String,
}
#[derive(Subdiagnostic)]
#[suggestion(
hir_typeck_convert_using_method,
code = "{sugg}",
applicability = "machine-applicable",
style = "verbose"
)]
pub struct SuggestConvertViaMethod<'tcx> {
#[primary_span]
pub span: Span,
pub sugg: &'static str,
pub expected: Ty<'tcx>,
pub found: Ty<'tcx>,
}

121
compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
View File

@ -1,6 +1,8 @@
use super::FnCtxt;
use crate::errors::{AddReturnTypeSuggestion, ExpectedReturnTypeLabel, SuggestBoxing};
use crate::errors::{
AddReturnTypeSuggestion, ExpectedReturnTypeLabel, SuggestBoxing, SuggestConvertViaMethod,
};
use crate::fluent_generated as fluent;
use crate::method::probe::{IsSuggestion, Mode, ProbeScope};
use rustc_ast::util::parser::{ExprPrecedence, PREC_POSTFIX};
@ -275,6 +277,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
expected_ty_expr: Option<&'tcx hir::Expr<'tcx>>,
) -> bool {
let expr = expr.peel_blocks();
let methods = self.get_conversion_methods(expr.span, expected, found, expr.hir_id);
if let Some((suggestion, msg, applicability, verbose, annotation)) =
self.suggest_deref_or_ref(expr, found, expected)
{
@ -325,9 +329,13 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
}
}
return true;
} else if self.suggest_else_fn_with_closure(err, expr, found, expected) {
}
if self.suggest_else_fn_with_closure(err, expr, found, expected) {
return true;
} else if self.suggest_fn_call(err, expr, found, |output| self.can_coerce(output, expected))
}
if self.suggest_fn_call(err, expr, found, |output| self.can_coerce(output, expected))
&& let ty::FnDef(def_id, ..) = *found.kind()
&& let Some(sp) = self.tcx.hir().span_if_local(def_id)
{
@ -343,12 +351,15 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
err.span_label(sp, format!("{descr} `{name}` defined here"));
}
return true;
} else if self.suggest_cast(err, expr, found, expected, expected_ty_expr) {
}
if self.suggest_cast(err, expr, found, expected, expected_ty_expr) {
return true;
} else {
let methods = self.get_conversion_methods(expr.span, expected, found, expr.hir_id);
}
if !methods.is_empty() {
let mut suggestions = methods.iter()
let mut suggestions = methods
.iter()
.filter_map(|conversion_method| {
let receiver_method_ident = expr.method_ident();
if let Some(method_ident) = receiver_method_ident
@ -380,12 +391,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
} else {
vec![(expr.span.shrink_to_hi(), format!(".{}()", conversion_method.name))]
};
let struct_pat_shorthand_field = self.maybe_get_struct_pattern_shorthand_field(expr);
let struct_pat_shorthand_field =
self.maybe_get_struct_pattern_shorthand_field(expr);
if let Some(name) = struct_pat_shorthand_field {
sugg.insert(
0,
(expr.span.shrink_to_lo(), format!("{}: ", name)),
);
sugg.insert(0, (expr.span.shrink_to_lo(), format!("{}: ", name)));
}
Some(sugg)
})
@ -398,42 +407,86 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
);
return true;
}
} else if let ty::Adt(found_adt, found_substs) = found.kind()
&& self.tcx.is_diagnostic_item(sym::Option, found_adt.did())
&& let ty::Adt(expected_adt, expected_substs) = expected.kind()
&& self.tcx.is_diagnostic_item(sym::Option, expected_adt.did())
&& let ty::Ref(_, inner_ty, _) = expected_substs.type_at(0).kind()
&& inner_ty.is_str()
{
let ty = found_substs.type_at(0);
let mut peeled = ty;
let mut ref_cnt = 0;
while let ty::Ref(_, inner, _) = peeled.kind() {
peeled = *inner;
ref_cnt += 1;
}
if let ty::Adt(adt, _) = peeled.kind()
&& Some(adt.did()) == self.tcx.lang_items().string()
if let Some((found_ty_inner, expected_ty_inner, error_tys)) =
self.deconstruct_option_or_result(found, expected)
&& let ty::Ref(_, peeled, hir::Mutability::Not) = *expected_ty_inner.kind()
{
// Check that given `Result<_, E>`, our expected ty is `Result<_, &E>`
let error_tys_equate_as_ref = error_tys.map_or(true, |(found, expected)| {
self.can_eq(self.param_env, self.tcx.mk_imm_ref(self.tcx.lifetimes.re_erased, found), expected)
});
// FIXME: This could/should be extended to suggest `as_mut` and `as_deref_mut`,
// but those checks need to be a bit more delicate and the benefit is diminishing.
if self.can_eq(self.param_env, found_ty_inner, peeled) && error_tys_equate_as_ref {
err.subdiagnostic(SuggestConvertViaMethod {
span: expr.span.shrink_to_hi(),
sugg: ".as_ref()",
expected,
found,
});
return true;
} else if let Some((deref_ty, _)) =
self.autoderef(expr.span, found_ty_inner).silence_errors().nth(1)
&& self.can_eq(self.param_env, deref_ty, peeled)
&& error_tys_equate_as_ref
{
err.subdiagnostic(SuggestConvertViaMethod {
span: expr.span.shrink_to_hi(),
sugg: ".as_deref()",
expected,
found,
});
return true;
} else if let ty::Adt(adt, _) = found_ty_inner.peel_refs().kind()
&& Some(adt.did()) == self.tcx.lang_items().string()
&& peeled.is_str()
&& error_tys.map_or(true, |(found, expected)| {
self.can_eq(self.param_env, found, expected)
})
{
let sugg = if ref_cnt == 0 {
".as_deref()"
} else {
".map(|x| x.as_str())"
};
err.span_suggestion_verbose(
expr.span.shrink_to_hi(),
fluent::hir_typeck_convert_to_str,
sugg,
".map(|x| x.as_str())",
Applicability::MachineApplicable,
);
return true;
}
}
}
false
}
fn deconstruct_option_or_result(
&self,
found_ty: Ty<'tcx>,
expected_ty: Ty<'tcx>,
) -> Option<(Ty<'tcx>, Ty<'tcx>, Option<(Ty<'tcx>, Ty<'tcx>)>)> {
let ty::Adt(found_adt, found_substs) = found_ty.peel_refs().kind() else {
return None;
};
let ty::Adt(expected_adt, expected_substs) = expected_ty.kind() else {
return None;
};
if self.tcx.is_diagnostic_item(sym::Option, found_adt.did())
&& self.tcx.is_diagnostic_item(sym::Option, expected_adt.did())
{
Some((found_substs.type_at(0), expected_substs.type_at(0), None))
} else if self.tcx.is_diagnostic_item(sym::Result, found_adt.did())
&& self.tcx.is_diagnostic_item(sym::Result, expected_adt.did())
{
Some((
found_substs.type_at(0),
expected_substs.type_at(0),
Some((found_substs.type_at(1), expected_substs.type_at(1))),
))
} else {
None
}
}
/// When encountering the expected boxed value allocated in the stack, suggest allocating it
/// in the heap by calling `Box::new()`.
pub(in super::super) fn suggest_boxing_when_appropriate(

3
compiler/rustc_infer/messages.ftl
View File

@ -278,9 +278,6 @@ infer_ril_introduced_by = requirement introduced by this return type
infer_ril_introduced_here = `'static` requirement introduced here
infer_ril_static_introduced_by = "`'static` lifetime requirement introduced by the return type
infer_sarwa_option = you can convert from `&Option<T>` to `Option<&T>` using `.as_ref()`
infer_sarwa_result = you can convert from `&Result<T, E>` to `Result<&T, &E>` using `.as_ref()`
infer_sbfrit_box_return_expr = if you change the return type to expect trait objects, box the returned expressions
infer_sbfrit_change_return_type = you could change the return type to be a boxed trait object

24
compiler/rustc_infer/src/errors/mod.rs
View File

@ -1246,30 +1246,6 @@ pub struct FnConsiderCasting {
pub casting: String,
}
#[derive(Subdiagnostic)]
pub enum SuggestAsRefWhereAppropriate<'a> {
#[suggestion(
infer_sarwa_option,
code = "{snippet}.as_ref()",
applicability = "machine-applicable"
)]
Option {
#[primary_span]
span: Span,
snippet: &'a str,
},
#[suggestion(
infer_sarwa_result,
code = "{snippet}.as_ref()",
applicability = "machine-applicable"
)]
Result {
#[primary_span]
span: Span,
snippet: &'a str,
},
}
#[derive(Subdiagnostic)]
pub enum SuggestAccessingField<'a> {
#[suggestion(

1
compiler/rustc_infer/src/infer/error_reporting/mod.rs
View File

@ -1897,7 +1897,6 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
if should_suggest_fixes {
self.suggest_tuple_pattern(cause, &exp_found, diag);
self.suggest_as_ref_where_appropriate(span, &exp_found, diag);
self.suggest_accessing_field_where_appropriate(cause, &exp_found, diag);
self.suggest_await_on_expect_found(cause, span, &exp_found, diag);
self.suggest_function_pointers(cause, span, &exp_found, diag);

27
compiler/rustc_infer/src/infer/error_reporting/suggest.rs
View File

@ -13,9 +13,9 @@ use rustc_span::{sym, BytePos, Span};
use crate::errors::{
ConsiderAddingAwait, FnConsiderCasting, FnItemsAreDistinct, FnUniqTypes,
FunctionPointerSuggestion, SuggestAccessingField, SuggestAsRefWhereAppropriate,
SuggestBoxingForReturnImplTrait, SuggestRemoveSemiOrReturnBinding, SuggestTuplePatternMany,
SuggestTuplePatternOne, TypeErrorAdditionalDiags,
FunctionPointerSuggestion, SuggestAccessingField, SuggestBoxingForReturnImplTrait,
SuggestRemoveSemiOrReturnBinding, SuggestTuplePatternMany, SuggestTuplePatternOne,
TypeErrorAdditionalDiags,
};
use super::TypeErrCtxt;
@ -289,27 +289,6 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
}
}
/// When encountering a case where `.as_ref()` on a `Result` or `Option` would be appropriate,
/// suggests it.
pub(super) fn suggest_as_ref_where_appropriate(
&self,
span: Span,
exp_found: &ty::error::ExpectedFound<Ty<'tcx>>,
diag: &mut Diagnostic,
) {
if let Ok(snippet) = self.tcx.sess.source_map().span_to_snippet(span)
&& let Some(msg) = self.should_suggest_as_ref_kind(exp_found.expected, exp_found.found)
{
// HACK: fix issue# 100605, suggesting convert from &Option<T> to Option<&T>, remove the extra `&`
let snippet = snippet.trim_start_matches('&');
let subdiag = match msg {
SuggestAsRefKind::Option => SuggestAsRefWhereAppropriate::Option { span, snippet },
SuggestAsRefKind::Result => SuggestAsRefWhereAppropriate::Result { span, snippet },
};
diag.subdiagnostic(subdiag);
}
}
pub(super) fn suggest_function_pointers(
&self,
cause: &ObligationCause<'tcx>,

14
tests/ui/issues/issue-100605.stderr
View File

@ -13,10 +13,6 @@ note: function defined here
|
LL | fn takes_option(_arg: Option<&String>) {}
| ^^^^^^^^^^^^ ---------------------
help: you can convert from `&Option<T>` to `Option<&T>` using `.as_ref()`
|
LL | takes_option(None.as_ref());
| ~~~~~~~~~~~~~
help: consider removing the borrow
|
LL - takes_option(&None);
@ -27,10 +23,8 @@ error[E0308]: mismatched types
--> $DIR/issue-100605.rs:8:18
|
LL | takes_option(&res);
| ------------ ^^^^
| | |
| | expected `Option<&String>`, found `&Option<String>`
| | help: you can convert from `&Option<T>` to `Option<&T>` using `.as_ref()`: `res.as_ref()`
| ------------ ^^^^ expected `Option<&String>`, found `&Option<String>`
| |
| arguments to this function are incorrect
|
= note: expected enum `Option<&String>`
@ -40,6 +34,10 @@ note: function defined here
|
LL | fn takes_option(_arg: Option<&String>) {}
| ^^^^^^^^^^^^ ---------------------
help: try using `.as_ref()` to convert `&Option<String>` to `Option<&String>`
|
LL | takes_option(&res.as_ref());
| +++++++++
error: aborting due to 2 previous errors

16
tests/ui/let-else/let-else-ref-bindings.stderr
View File

@ -6,6 +6,10 @@ LL | let Some(ref a): Option<&[u8]> = some else { return };
|
= note: expected enum `Option<&[u8]>`
found enum `Option<Vec<u8>>`
help: try using `.as_deref()` to convert `Option<Vec<u8>>` to `Option<&[u8]>`
|
LL | let Some(ref a): Option<&[u8]> = some.as_deref() else { return };
| +++++++++++
error[E0308]: mismatched types
--> $DIR/let-else-ref-bindings.rs:20:38
@ -15,6 +19,10 @@ LL | let Some(ref a): Option<&[u8]> = &some else { return };
|
= note: expected enum `Option<&[u8]>`
found reference `&Option<Vec<u8>>`
help: try using `.as_deref()` to convert `&Option<Vec<u8>>` to `Option<&[u8]>`
|
LL | let Some(ref a): Option<&[u8]> = &some.as_deref() else { return };
| +++++++++++
error[E0308]: mismatched types
--> $DIR/let-else-ref-bindings.rs:24:34
@ -26,6 +34,10 @@ LL | let Some(a): Option<&[u8]> = some else { return };
|
= note: expected enum `Option<&[u8]>`
found enum `Option<Vec<u8>>`
help: try using `.as_deref()` to convert `Option<Vec<u8>>` to `Option<&[u8]>`
|
LL | let Some(a): Option<&[u8]> = some.as_deref() else { return };
| +++++++++++
error[E0308]: mismatched types
--> $DIR/let-else-ref-bindings.rs:27:34
@ -37,6 +49,10 @@ LL | let Some(a): Option<&[u8]> = &some else { return };
|
= note: expected enum `Option<&[u8]>`
found reference `&Option<Vec<u8>>`
help: try using `.as_deref()` to convert `&Option<Vec<u8>>` to `Option<&[u8]>`
|
LL | let Some(a): Option<&[u8]> = &some.as_deref() else { return };
| +++++++++++
error[E0308]: mismatched types
--> $DIR/let-else-ref-bindings.rs:44:46

2
tests/ui/suggestions/as-ref.rs
View File

@ -24,4 +24,6 @@ fn main() {
let multiple_ref_result = &&Ok(Foo);
multiple_ref_result.map(|arg| takes_ref(arg)); //~ ERROR mismatched types [E0308]
multiple_ref_result.and_then(|arg| Ok(takes_ref(arg))); //~ ERROR mismatched types [E0308]
let _: Result<&usize, _> = &Ok(42); //~ ERROR mismatched types [E0308]
}

32
tests/ui/suggestions/as-ref.stderr
View File

@ -74,14 +74,16 @@ error[E0308]: mismatched types
--> $DIR/as-ref.rs:13:29
|
LL | let y: Option<&usize> = x;
| -------------- ^
| | |
| | expected `Option<&usize>`, found `&Option<usize>`
| | help: you can convert from `&Option<T>` to `Option<&T>` using `.as_ref()`: `x.as_ref()`
| -------------- ^ expected `Option<&usize>`, found `&Option<usize>`
| |
| expected due to this
|
= note: expected enum `Option<&usize>`
found reference `&Option<usize>`
help: try using `.as_ref()` to convert `&Option<usize>` to `Option<&usize>`
|
LL | let y: Option<&usize> = x.as_ref();
| +++++++++
error[E0308]: mismatched types
--> $DIR/as-ref.rs:15:37
@ -93,10 +95,10 @@ LL | let y: Result<&usize, &usize> = x;
|
= note: expected enum `Result<&usize, &usize>`
found reference `&Result<usize, usize>`
help: you can convert from `&Result<T, E>` to `Result<&T, &E>` using `.as_ref()`
help: try using `.as_ref()` to convert `&Result<usize, usize>` to `Result<&usize, &usize>`
|
LL | let y: Result<&usize, &usize> = x.as_ref();
| ~~~~~~~~~~
| +++++++++
error[E0308]: mismatched types
--> $DIR/as-ref.rs:19:36
@ -181,6 +183,22 @@ help: consider using `as_ref` instead
LL | multiple_ref_result.as_ref().and_then(|arg| Ok(takes_ref(arg)));
| +++++++++
error: aborting due to 11 previous errors
error[E0308]: mismatched types
--> $DIR/as-ref.rs:28:32
|
LL | let _: Result<&usize, _> = &Ok(42);
| ----------------- ^^^^^^^ expected `Result<&usize, _>`, found `&Result<{integer}, _>`
| |
| expected due to this
|
= note: expected enum `Result<&usize, _>`
found reference `&Result<{integer}, _>`
help: try using `.as_ref()` to convert `&Result<{integer}, _>` to `Result<&usize, _>`
|
LL - let _: Result<&usize, _> = &Ok(42);
LL + let _: Result<&usize, _> = Ok(42).as_ref();
|
error: aborting due to 12 previous errors
For more information about this error, try `rustc --explain E0308`.

2
tests/ui/typeck/issue-89856.stderr
View File

@ -13,7 +13,7 @@ note: function defined here
|
LL | fn take_str_maybe(_: Option<&str>) { }
| ^^^^^^^^^^^^^^ ---------------
help: try converting the passed type into a `&str`
help: try using `.as_deref()` to convert `Option<String>` to `Option<&str>`
|
LL | take_str_maybe(option.as_deref());
| +++++++++++