bjoernager/rust
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macros: add diagnostic derive for lints

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`SessionDiagnostic` isn't suitable for use on lints as whether or not it
creates an error or a warning is decided at compile-time by the macro,
whereas lints decide this at runtime based on the location of the lint
being reported (as it will depend on the user's `allow`/`deny`
attributes, etc). Re-using most of the machinery for
`SessionDiagnostic`, this macro introduces a `LintDiagnostic` derive
which implements a `DecorateLint` trait, taking a
`LintDiagnosticBuilder` and adding to the lint according to the
diagnostic struct.
This commit is contained in:
David Wood 2022-06-30 08:57:45 +01:00
parent 7f9d8480d6
commit 9d864c8d56
12 changed files with 847 additions and 614 deletions
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20
compiler/rustc_macros/src/diagnostics/utils.rs
View file

@ -1,4 +1,4 @@
use crate::diagnostics::error::{span_err, throw_span_err, SessionDiagnosticDeriveError};
use crate::diagnostics::error::{span_err, throw_span_err, DiagnosticDeriveError};
use proc_macro::Span;
use proc_macro2::TokenStream;
use quote::{format_ident, quote, ToTokens};
@ -34,7 +34,7 @@ pub(crate) fn type_is_unit(ty: &Type) -> bool {
pub(crate) fn report_type_error(
attr: &Attribute,
ty_name: &str,
) -> Result<!, SessionDiagnosticDeriveError> {
) -> Result<!, DiagnosticDeriveError> {
let name = attr.path.segments.last().unwrap().ident.to_string();
let meta = attr.parse_meta()?;
@ -59,7 +59,7 @@ fn report_error_if_not_applied_to_ty(
info: &FieldInfo<'_>,
path: &[&str],
ty_name: &str,
) -> Result<(), SessionDiagnosticDeriveError> {
) -> Result<(), DiagnosticDeriveError> {
if !type_matches_path(&info.ty, path) {
report_type_error(attr, ty_name)?;
}
@ -71,7 +71,7 @@ fn report_error_if_not_applied_to_ty(
pub(crate) fn report_error_if_not_applied_to_applicability(
attr: &Attribute,
info: &FieldInfo<'_>,
) -> Result<(), SessionDiagnosticDeriveError> {
) -> Result<(), DiagnosticDeriveError> {
report_error_if_not_applied_to_ty(
attr,
info,
@ -84,7 +84,7 @@ pub(crate) fn report_error_if_not_applied_to_applicability(
pub(crate) fn report_error_if_not_applied_to_span(
attr: &Attribute,
info: &FieldInfo<'_>,
) -> Result<(), SessionDiagnosticDeriveError> {
) -> Result<(), DiagnosticDeriveError> {
report_error_if_not_applied_to_ty(attr, info, &["rustc_span", "Span"], "`Span`")
}
@ -166,10 +166,12 @@ pub(crate) struct FieldInfo<'a> {
/// Small helper trait for abstracting over `Option` fields that contain a value and a `Span`
/// for error reporting if they are set more than once.
pub(crate) trait SetOnce<T> {
fn set_once(&mut self, value: T);
fn set_once(&mut self, _: (T, Span));
fn value(self) -> Option<T>;
}
impl<T> SetOnce<(T, Span)> for Option<(T, Span)> {
impl<T> SetOnce<T> for Option<(T, Span)> {
fn set_once(&mut self, (value, span): (T, Span)) {
match self {
None => {
@ -182,6 +184,10 @@ impl<T> SetOnce<(T, Span)> for Option<(T, Span)> {
}
}
}
fn value(self) -> Option<T> {
self.map(|(v, _)| v)
}
}
pub(crate) trait HasFieldMap {