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Rollup merge of #104504 - compiler-errors:fru-syntax-note, r=estebank

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Add a detailed note for missing comma typo w/ FRU syntax

Thanks to `@pierwill` for working on this with me!

Fixes #104373, perhaps `@alice-i-cecile` can comment on the new error for the example provided on that issue -- feedback is welcome.

```
error[E0063]: missing field `defaulted` in initializer of `Outer`
  --> $DIR/multi-line-fru-suggestion.rs:14:5
   |
LL |     Outer {
   |     ^^^^^ missing `defaulted`
   |
note: this expression may have been misinterpreted as a `..` range expression
  --> $DIR/multi-line-fru-suggestion.rs:16:16
   |
LL |           inner: Inner {
   |  ________________^
LL | |             a: 1,
LL | |             b: 2,
LL | |         }
   | |_________^ this expression does not end in a comma...
LL |           ..Default::default()
   |           ^^^^^^^^^^^^^^^^^^^^ ... so this is interpreted as a `..` range expression, instead of functional record update syntax
help: to set the remaining fields from `Default::default()`, separate the last named field with a comma
   |
LL |         },
   |          +

error: aborting due to previous error

For more information about this error, try `rustc --explain E0063`.
```
This commit is contained in:
Matthias Krüger 2022-11-20 23:50:27 +01:00 committed by GitHub
commit fce077b053
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GPG Key ID: 4AEE18F83AFDEB23
10 changed files with 155 additions and 31 deletions
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8
compiler/rustc_error_messages/locales/en-US/hir_typeck.ftl Normal file
View File

@ -0,0 +1,8 @@
hir_typeck_fru_note = this expression may have been misinterpreted as a `..` range expression
hir_typeck_fru_expr = this expression does not end in a comma...
hir_typeck_fru_expr2 = ... so this is interpreted as a `..` range expression, instead of functional record update syntax
hir_typeck_fru_suggestion =
to set the remaining fields{$expr ->
[NONE]{""}
*[other] {" "}from `{$expr}`
}, separate the last named field with a comma

1
compiler/rustc_error_messages/src/lib.rs
View File

@ -51,6 +51,7 @@
errors => "../locales/en-US/errors.ftl",
expand => "../locales/en-US/expand.ftl",
hir_analysis => "../locales/en-US/hir_analysis.ftl",
hir_typeck => "../locales/en-US/hir_typeck.ftl",
infer => "../locales/en-US/infer.ftl",
interface => "../locales/en-US/interface.ftl",
lint => "../locales/en-US/lint.ftl",

3
compiler/rustc_errors/src/lib.rs
View File

@ -467,6 +467,9 @@ pub enum StashKey {
/// When an invalid lifetime e.g. `'2` should be reinterpreted
/// as a char literal in the parser
LifetimeIsChar,
/// Maybe there was a typo where a comma was forgotten before
/// FRU syntax
MaybeFruTypo,
}
fn default_track_diagnostic(_: &Diagnostic) {}

39
compiler/rustc_hir_typeck/src/errors.rs
View File

@ -1,4 +1,5 @@
//! Errors emitted by `rustc_hir_analysis`.
use rustc_errors::{AddToDiagnostic, Applicability, Diagnostic, MultiSpan, SubdiagnosticMessage};
use rustc_macros::{Diagnostic, Subdiagnostic};
use rustc_middle::ty::Ty;
use rustc_span::{symbol::Ident, Span};
@ -133,3 +134,41 @@ pub struct OpMethodGenericParams {
pub span: Span,
pub method_name: String,
}
pub struct TypeMismatchFruTypo {
/// Span of the LHS of the range
pub expr_span: Span,
/// Span of the `..RHS` part of the range
pub fru_span: Span,
/// Rendered expression of the RHS of the range
pub expr: Option<String>,
}
impl AddToDiagnostic for TypeMismatchFruTypo {
fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
where
F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
{
diag.set_arg("expr", self.expr.as_deref().unwrap_or("NONE"));
// Only explain that `a ..b` is a range if it's split up
if self.expr_span.between(self.fru_span).is_empty() {
diag.span_note(
self.expr_span.to(self.fru_span),
rustc_errors::fluent::hir_typeck_fru_note,
);
} else {
let mut multispan: MultiSpan = vec![self.expr_span, self.fru_span].into();
multispan.push_span_label(self.expr_span, rustc_errors::fluent::hir_typeck_fru_expr);
multispan.push_span_label(self.fru_span, rustc_errors::fluent::hir_typeck_fru_expr2);
diag.span_note(multispan, rustc_errors::fluent::hir_typeck_fru_note);
}
diag.span_suggestion(
self.expr_span.shrink_to_hi(),
rustc_errors::fluent::hir_typeck_fru_suggestion,
", ",
Applicability::MaybeIncorrect,
);
}
}

51
compiler/rustc_hir_typeck/src/expr.rs
View File

@ -5,6 +5,7 @@
use crate::cast;
use crate::coercion::CoerceMany;
use crate::coercion::DynamicCoerceMany;
use crate::errors::TypeMismatchFruTypo;
use crate::errors::{AddressOfTemporaryTaken, ReturnStmtOutsideOfFnBody, StructExprNonExhaustive};
use crate::errors::{
FieldMultiplySpecifiedInInitializer, FunctionalRecordUpdateOnNonStruct,
@ -1616,10 +1617,16 @@ fn check_expr_struct_fields(
self.demand_coerce_diag(&field.expr, ty, field_type, None, AllowTwoPhase::No);
if let Some(mut diag) = diag {
if idx == ast_fields.len() - 1 && remaining_fields.is_empty() {
self.suggest_fru_from_range(field, variant, substs, &mut diag);
if idx == ast_fields.len() - 1 {
if remaining_fields.is_empty() {
self.suggest_fru_from_range(field, variant, substs, &mut diag);
diag.emit();
} else {
diag.stash(field.span, StashKey::MaybeFruTypo);
}
} else {
diag.emit();
}
diag.emit();
}
}
@ -1877,19 +1884,39 @@ fn suggest_fru_from_range(
.map(|adt| adt.did())
!= range_def_id
{
let instead = self
// Suppress any range expr type mismatches
if let Some(mut diag) = self
.tcx
.sess
.diagnostic()
.steal_diagnostic(last_expr_field.span, StashKey::MaybeFruTypo)
{
diag.delay_as_bug();
}
// Use a (somewhat arbitrary) filtering heuristic to avoid printing
// expressions that are either too long, or have control character
//such as newlines in them.
let expr = self
.tcx
.sess
.source_map()
.span_to_snippet(range_end.expr.span)
.map(|s| format!(" from `{s}`"))
.unwrap_or_default();
err.span_suggestion(
range_start.span.shrink_to_hi(),
&format!("to set the remaining fields{instead}, separate the last named field with a comma"),
",",
Applicability::MaybeIncorrect,
);
.ok()
.filter(|s| s.len() < 25 && !s.contains(|c: char| c.is_control()));
let fru_span = self
.tcx
.sess
.source_map()
.span_extend_while(range_start.span, |c| c.is_whitespace())
.unwrap_or(range_start.span).shrink_to_hi().to(range_end.span);
err.subdiagnostic(TypeMismatchFruTypo {
expr_span: range_start.span,
fru_span,
expr,
});
}
}

22
src/test/ui/structs/multi-line-fru-suggestion.rs Normal file
View File

@ -0,0 +1,22 @@
#[derive(Default)]
struct Inner {
a: u8,
b: u8,
}
#[derive(Default)]
struct Outer {
inner: Inner,
defaulted: u8,
}
fn main(){
Outer {
//~^ ERROR missing field `defaulted` in initializer of `Outer`
inner: Inner {
a: 1,
b: 2,
}
..Default::default()
};
}

25
src/test/ui/structs/multi-line-fru-suggestion.stderr Normal file
View File

@ -0,0 +1,25 @@
error[E0063]: missing field `defaulted` in initializer of `Outer`
--> $DIR/multi-line-fru-suggestion.rs:14:5
|
LL | Outer {
| ^^^^^ missing `defaulted`
|
note: this expression may have been misinterpreted as a `..` range expression
--> $DIR/multi-line-fru-suggestion.rs:16:16
|
LL | inner: Inner {
| ________________^
LL | | a: 1,
LL | | b: 2,
LL | | }
| |_________^ this expression does not end in a comma...
LL | ..Default::default()
| ^^^^^^^^^^^^^^^^^^^^ ... so this is interpreted as a `..` range expression, instead of functional record update syntax
help: to set the remaining fields from `Default::default()`, separate the last named field with a comma
|
LL | },
| +
error: aborting due to previous error
For more information about this error, try `rustc --explain E0063`.

7
src/test/ui/structs/struct-record-suggestion.fixed
View File

@ -7,9 +7,8 @@ struct A {
}
fn a() {
let q = A { c: 5,..Default::default() };
//~^ ERROR mismatched types
//~| ERROR missing fields
let q = A { c: 5, ..Default::default() };
//~^ ERROR missing fields
//~| HELP separate the last named field with a comma
let r = A { c: 5, ..Default::default() };
assert_eq!(q, r);
@ -21,7 +20,7 @@ struct B {
}
fn b() {
let q = B { b: 1,..Default::default() };
let q = B { b: 1, ..Default::default() };
//~^ ERROR mismatched types
//~| HELP separate the last named field with a comma
let r = B { b: 1 };

3
src/test/ui/structs/struct-record-suggestion.rs
View File

@ -8,8 +8,7 @@ struct A {
fn a() {
let q = A { c: 5..Default::default() };
//~^ ERROR mismatched types
//~| ERROR missing fields
//~^ ERROR missing fields
//~| HELP separate the last named field with a comma
let r = A { c: 5, ..Default::default() };
assert_eq!(q, r);

27
src/test/ui/structs/struct-record-suggestion.stderr
View File

@ -1,37 +1,38 @@
error[E0308]: mismatched types
--> $DIR/struct-record-suggestion.rs:10:20
|
LL | let q = A { c: 5..Default::default() };
| ^^^^^^^^^^^^^^^^^^^^^ expected `u64`, found struct `std::ops::Range`
|
= note: expected type `u64`
found struct `std::ops::Range<{integer}>`
error[E0063]: missing fields `b` and `d` in initializer of `A`
--> $DIR/struct-record-suggestion.rs:10:13
|
LL | let q = A { c: 5..Default::default() };
| ^ missing `b` and `d`
|
note: this expression may have been misinterpreted as a `..` range expression
--> $DIR/struct-record-suggestion.rs:10:20
|
LL | let q = A { c: 5..Default::default() };
| ^^^^^^^^^^^^^^^^^^^^^
help: to set the remaining fields from `Default::default()`, separate the last named field with a comma
|
LL | let q = A { c: 5,..Default::default() };
LL | let q = A { c: 5, ..Default::default() };
| +
error[E0308]: mismatched types
--> $DIR/struct-record-suggestion.rs:24:20
--> $DIR/struct-record-suggestion.rs:23:20
|
LL | let q = B { b: 1..Default::default() };
| ^^^^^^^^^^^^^^^^^^^^^ expected `u32`, found struct `std::ops::Range`
|
= note: expected type `u32`
found struct `std::ops::Range<{integer}>`
note: this expression may have been misinterpreted as a `..` range expression
--> $DIR/struct-record-suggestion.rs:23:20
|
LL | let q = B { b: 1..Default::default() };
| ^^^^^^^^^^^^^^^^^^^^^
help: to set the remaining fields from `Default::default()`, separate the last named field with a comma
|
LL | let q = B { b: 1,..Default::default() };
LL | let q = B { b: 1, ..Default::default() };
| +
error: aborting due to 3 previous errors
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0063, E0308.
For more information about an error, try `rustc --explain E0063`.