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macros: spanless subdiagnostics from () fields

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Type attributes could previously be used to support spanless
subdiagnostics but these couldn't easily be made optional in the same
way that spanned subdiagnostics could by using a field attribute on a
field with an `Option<Span>` type. Spanless subdiagnostics can now be
specified on fields with `()` type or `Option<()>` type.

Signed-off-by: David Wood <david.wood@huawei.com>
This commit is contained in:
David Wood 2022-05-07 06:02:11 +01:00
parent 1d2ea98cff
commit 7b7061dd89
4 changed files with 97 additions and 33 deletions
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53
compiler/rustc_macros/src/diagnostics/diagnostic.rs
View File

@ -5,10 +5,10 @@ use crate::diagnostics::error::{
SessionDiagnosticDeriveError,
};
use crate::diagnostics::utils::{
report_error_if_not_applied_to_span, type_matches_path, Applicability, FieldInfo, FieldInnerTy,
HasFieldMap, SetOnce,
report_error_if_not_applied_to_span, report_type_error, type_is_unit, type_matches_path,
Applicability, FieldInfo, FieldInnerTy, HasFieldMap, SetOnce,
};
use proc_macro2::TokenStream;
use proc_macro2::{Ident, TokenStream};
use quote::{format_ident, quote};
use std::collections::HashMap;
use std::str::FromStr;
@ -388,7 +388,8 @@ impl SessionDiagnosticDeriveBuilder {
) -> Result<TokenStream, SessionDiagnosticDeriveError> {
let diag = &self.diag;
let name = attr.path.segments.last().unwrap().ident.to_string();
let ident = &attr.path.segments.last().unwrap().ident;
let name = ident.to_string();
let name = name.as_str();
let meta = attr.parse_meta()?;
@ -405,9 +406,18 @@ impl SessionDiagnosticDeriveBuilder {
#diag.set_span(#binding);
})
}
"label" | "note" | "help" => {
"label" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(self.add_subdiagnostic(binding, name, name))
Ok(self.add_spanned_subdiagnostic(binding, ident, name))
}
"note" | "help" => {
if type_matches_path(&info.ty, &["rustc_span", "Span"]) {
Ok(self.add_spanned_subdiagnostic(binding, ident, name))
} else if type_is_unit(&info.ty) {
Ok(self.add_subdiagnostic(ident, name))
} else {
report_type_error(attr, "`Span` or `()`")?;
}
}
"subdiagnostic" => Ok(quote! { #diag.subdiagnostic(#binding); }),
_ => throw_invalid_attr!(attr, &meta, |diag| {
@ -416,9 +426,18 @@ impl SessionDiagnosticDeriveBuilder {
}),
},
Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(ref s), .. }) => match name {
"label" | "note" | "help" => {
"label" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(self.add_subdiagnostic(binding, name, &s.value()))
Ok(self.add_spanned_subdiagnostic(binding, ident, &s.value()))
}
"note" | "help" => {
if type_matches_path(&info.ty, &["rustc_span", "Span"]) {
Ok(self.add_spanned_subdiagnostic(binding, ident, &s.value()))
} else if type_is_unit(&info.ty) {
Ok(self.add_subdiagnostic(ident, &s.value()))
} else {
report_type_error(attr, "`Span` or `()`")?;
}
}
_ => throw_invalid_attr!(attr, &meta, |diag| {
diag.help("only `label`, `note` and `help` are valid field attributes")
@ -510,12 +529,12 @@ impl SessionDiagnosticDeriveBuilder {
}
}
/// Adds a subdiagnostic by generating a `diag.span_$kind` call with the current slug and
/// `fluent_attr_identifier`.
fn add_subdiagnostic(
/// Adds a spanned subdiagnostic by generating a `diag.span_$kind` call with the current slug
/// and `fluent_attr_identifier`.
fn add_spanned_subdiagnostic(
&self,
field_binding: TokenStream,
kind: &str,
kind: &Ident,
fluent_attr_identifier: &str,
) -> TokenStream {
let diag = &self.diag;
@ -531,6 +550,16 @@ impl SessionDiagnosticDeriveBuilder {
}
}
/// Adds a subdiagnostic by generating a `diag.span_$kind` call with the current slug
/// and `fluent_attr_identifier`.
fn add_subdiagnostic(&self, kind: &Ident, fluent_attr_identifier: &str) -> TokenStream {
let diag = &self.diag;
let slug = self.slug.as_ref().map(|(slug, _)| slug.as_str()).unwrap_or("missing-slug");
quote! {
#diag.#kind(rustc_errors::DiagnosticMessage::fluent_attr(#slug, #fluent_attr_identifier));
}
}
fn span_and_applicability_of_ty(
&self,
info: FieldInfo<'_>,

54
compiler/rustc_macros/src/diagnostics/utils.rs
View File

@ -4,7 +4,7 @@ use proc_macro2::TokenStream;
use quote::{format_ident, quote, ToTokens};
use std::collections::BTreeSet;
use std::str::FromStr;
use syn::{spanned::Spanned, Attribute, Meta, Type, Visibility};
use syn::{spanned::Spanned, Attribute, Meta, Type, TypeTuple, Visibility};
use synstructure::BindingInfo;
/// Checks whether the type name of `ty` matches `name`.
@ -25,7 +25,35 @@ pub(crate) fn type_matches_path(ty: &Type, name: &[&str]) -> bool {
}
}
/// Reports an error if the field's type is not `Applicability`.
/// Checks whether the type `ty` is `()`.
pub(crate) fn type_is_unit(ty: &Type) -> bool {
if let Type::Tuple(TypeTuple { elems, .. }) = ty { elems.is_empty() } else { false }
}
/// Reports a type error for field with `attr`.
pub(crate) fn report_type_error(
attr: &Attribute,
ty_name: &str,
) -> Result<!, SessionDiagnosticDeriveError> {
let name = attr.path.segments.last().unwrap().ident.to_string();
let meta = attr.parse_meta()?;
throw_span_err!(
attr.span().unwrap(),
&format!(
"the `#[{}{}]` attribute can only be applied to fields of type {}",
name,
match meta {
Meta::Path(_) => "",
Meta::NameValue(_) => " = ...",
Meta::List(_) => "(...)",
},
ty_name
)
);
}
/// Reports an error if the field's type does not match `path`.
fn report_error_if_not_applied_to_ty(
attr: &Attribute,
info: &FieldInfo<'_>,
@ -33,23 +61,7 @@ fn report_error_if_not_applied_to_ty(
ty_name: &str,
) -> Result<(), SessionDiagnosticDeriveError> {
if !type_matches_path(&info.ty, path) {
let name = attr.path.segments.last().unwrap().ident.to_string();
let name = name.as_str();
let meta = attr.parse_meta()?;
throw_span_err!(
attr.span().unwrap(),
&format!(
"the `#[{}{}]` attribute can only be applied to fields of type `{}`",
name,
match meta {
Meta::Path(_) => "",
Meta::NameValue(_) => " = ...",
Meta::List(_) => "(...)",
},
ty_name
)
);
report_type_error(attr, ty_name)?;
}
Ok(())
@ -64,7 +76,7 @@ pub(crate) fn report_error_if_not_applied_to_applicability(
attr,
info,
&["rustc_errors", "Applicability"],
"Applicability",
"`Applicability`",
)
}
@ -73,7 +85,7 @@ pub(crate) fn report_error_if_not_applied_to_span(
attr: &Attribute,
info: &FieldInfo<'_>,
) -> Result<(), SessionDiagnosticDeriveError> {
report_error_if_not_applied_to_ty(attr, info, &["rustc_span", "Span"], "Span")
report_error_if_not_applied_to_ty(attr, info, &["rustc_span", "Span"], "`Span`")
}
/// Inner type of a field and type of wrapper.

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

@ -1,5 +1,6 @@
#![feature(allow_internal_unstable)]
#![feature(let_else)]
#![feature(never_type)]
#![feature(proc_macro_diagnostic)]
#![allow(rustc::default_hash_types)]
#![recursion_limit = "128"]

22
src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
View File

@ -482,3 +482,25 @@ struct VecField {
#[label]
spans: Vec<Span>,
}
#[derive(SessionDiagnostic)]
#[error(code = "E0123", slug = "foo")]
struct UnitField {
#[primary_span]
spans: Span,
#[help]
foo: (),
#[help = "a"]
bar: (),
}
#[derive(SessionDiagnostic)]
#[error(code = "E0123", slug = "foo")]
struct OptUnitField {
#[primary_span]
spans: Span,
#[help]
foo: Option<()>,
#[help = "a"]
bar: Option<()>,
}