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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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1
Cargo.lock
View File

@ -4009,6 +4009,7 @@ dependencies = [
"rustc_hir",
"rustc_index",
"rustc_infer",
"rustc_macros",
"rustc_middle",
"rustc_parse_format",
"rustc_session",

1
compiler/rustc_lint/Cargo.toml
View File

@ -22,3 +22,4 @@ rustc_trait_selection = { path = "../rustc_trait_selection" }
rustc_parse_format = { path = "../rustc_parse_format" }
rustc_infer = { path = "../rustc_infer" }
rustc_type_ir = { path = "../rustc_type_ir" }
rustc_macros = { path = "../rustc_macros" }

22
compiler/rustc_lint/src/types.rs
View File

@ -5,6 +5,7 @@ use rustc_data_structures::fx::FxHashSet;
use rustc_errors::{fluent, Applicability, DiagnosticMessage};
use rustc_hir as hir;
use rustc_hir::{is_range_literal, Expr, ExprKind, Node};
use rustc_macros::LintDiagnostic;
use rustc_middle::ty::layout::{IntegerExt, LayoutOf, SizeSkeleton};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::{self, AdtKind, DefIdTree, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable};
@ -1553,13 +1554,20 @@ impl InvalidAtomicOrdering {
let Some(fail_ordering) = Self::match_ordering(cx, fail_order_arg) else { return };
if matches!(fail_ordering, sym::Release | sym::AcqRel) {
cx.struct_span_lint(INVALID_ATOMIC_ORDERING, fail_order_arg.span, |diag| {
diag.build(fluent::lint::atomic_ordering_invalid)
.set_arg("method", method)
.span_label(fail_order_arg.span, fluent::lint::label)
.help(fluent::lint::help)
.emit();
});
#[derive(LintDiagnostic)]
#[lint(lint::atomic_ordering_invalid)]
#[help]
struct InvalidAtomicOrderingDiag {
method: Symbol,
#[label]
fail_order_arg_span: Span,
}
cx.emit_spanned_lint(
INVALID_ATOMIC_ORDERING,
fail_order_arg.span,
InvalidAtomicOrderingDiag { method, fail_order_arg_span: fail_order_arg.span },
);
}
let Some(success_ordering) = Self::match_ordering(cx, success_order_arg) else { return };

693
compiler/rustc_macros/src/diagnostics/diagnostic.rs
View File

@ -1,33 +1,24 @@
#![deny(unused_must_use)]
use crate::diagnostics::error::{
invalid_nested_attr, span_err, throw_invalid_attr, throw_invalid_nested_attr, throw_span_err,
SessionDiagnosticDeriveError,
};
use crate::diagnostics::utils::{
build_field_mapping, report_error_if_not_applied_to_span, report_type_error, type_is_unit,
type_matches_path, Applicability, FieldInfo, FieldInnerTy, HasFieldMap, SetOnce,
};
use proc_macro2::{Ident, TokenStream};
use quote::{format_ident, quote};
use std::collections::HashMap;
use std::str::FromStr;
use syn::{
parse_quote, spanned::Spanned, Attribute, Meta, MetaList, MetaNameValue, NestedMeta, Path, Type,
};
use synstructure::{BindingInfo, Structure};
use crate::diagnostics::diagnostic_builder::{DiagnosticDeriveBuilder, DiagnosticDeriveKind};
use crate::diagnostics::error::{span_err, DiagnosticDeriveError};
use crate::diagnostics::utils::{build_field_mapping, SetOnce};
use proc_macro2::TokenStream;
use quote::quote;
use syn::spanned::Spanned;
use synstructure::Structure;
/// The central struct for constructing the `into_diagnostic` method from an annotated struct.
pub(crate) struct SessionDiagnosticDerive<'a> {
structure: Structure<'a>,
sess: syn::Ident,
builder: SessionDiagnosticDeriveBuilder,
builder: DiagnosticDeriveBuilder,
}
impl<'a> SessionDiagnosticDerive<'a> {
pub(crate) fn new(diag: syn::Ident, sess: syn::Ident, structure: Structure<'a>) -> Self {
Self {
builder: SessionDiagnosticDeriveBuilder {
builder: DiagnosticDeriveBuilder {
diag,
fields: build_field_mapping(&structure),
kind: None,
@ -43,69 +34,21 @@ impl<'a> SessionDiagnosticDerive<'a> {
let SessionDiagnosticDerive { mut structure, sess, mut builder } = self;
let ast = structure.ast();
let attrs = &ast.attrs;
let (implementation, param_ty) = {
if let syn::Data::Struct(..) = ast.data {
let preamble = {
let preamble = attrs.iter().map(|attr| {
builder
.generate_structure_code(attr)
.unwrap_or_else(|v| v.to_compile_error())
});
quote! {
#(#preamble)*;
}
};
// Keep track of which fields are subdiagnostics or have no attributes.
let mut subdiagnostics_or_empty = std::collections::HashSet::new();
// Generates calls to `span_label` and similar functions based on the attributes
// on fields. Code for suggestions uses formatting machinery and the value of
// other fields - because any given field can be referenced multiple times, it
// should be accessed through a borrow. When passing fields to `add_subdiagnostic`
// or `set_arg` (which happens below) for Fluent, we want to move the data, so that
// has to happen in a separate pass over the fields.
let attrs = structure
.clone()
.filter(|field_binding| {
let attrs = &field_binding.ast().attrs;
(!attrs.is_empty()
&& attrs.iter().all(|attr| {
"subdiagnostic"
!= attr.path.segments.last().unwrap().ident.to_string()
}))
|| {
subdiagnostics_or_empty.insert(field_binding.binding.clone());
false
}
})
.each(|field_binding| builder.generate_field_attrs_code(field_binding));
structure.bind_with(|_| synstructure::BindStyle::Move);
// When a field has attributes like `#[label]` or `#[note]` then it doesn't
// need to be passed as an argument to the diagnostic. But when a field has no
// attributes or a `#[subdiagnostic]` attribute then it must be passed as an
// argument to the diagnostic so that it can be referred to by Fluent messages.
let args = structure
.filter(|field_binding| {
subdiagnostics_or_empty.contains(&field_binding.binding)
})
.each(|field_binding| builder.generate_field_attrs_code(field_binding));
let preamble = builder.preamble(&structure);
let (attrs, args) = builder.body(&mut structure);
let span = ast.span().unwrap();
let diag = &builder.diag;
let init = match (builder.kind, builder.slug) {
let init = match (builder.kind.value(), builder.slug.value()) {
(None, _) => {
span_err(span, "diagnostic kind not specified")
.help("use the `#[error(...)]` attribute to create an error")
.emit();
return SessionDiagnosticDeriveError::ErrorHandled.to_compile_error();
return DiagnosticDeriveError::ErrorHandled.to_compile_error();
}
(Some((kind, _)), None) => {
(Some(kind), None) => {
span_err(span, "diagnostic slug not specified")
.help(&format!(
"specify the slug as the first argument to the attribute, such as \
@ -113,14 +56,20 @@ impl<'a> SessionDiagnosticDerive<'a> {
kind.descr()
))
.emit();
return SessionDiagnosticDeriveError::ErrorHandled.to_compile_error();
return DiagnosticDeriveError::ErrorHandled.to_compile_error();
}
(Some((SessionDiagnosticKind::Error, _)), Some((slug, _))) => {
(Some(DiagnosticDeriveKind::Lint), _) => {
span_err(span, "only `#[error(..)]` and `#[warn(..)]` are supported")
.help("use the `#[error(...)]` attribute to create a error")
.emit();
return DiagnosticDeriveError::ErrorHandled.to_compile_error();
}
(Some(DiagnosticDeriveKind::Error), Some(slug)) => {
quote! {
let mut #diag = #sess.struct_err(rustc_errors::fluent::#slug);
}
}
(Some((SessionDiagnosticKind::Warn, _)), Some((slug, _))) => {
(Some(DiagnosticDeriveKind::Warn), Some(slug)) => {
quote! {
let mut #diag = #sess.struct_warn(rustc_errors::fluent::#slug);
}
@ -139,10 +88,12 @@ impl<'a> SessionDiagnosticDerive<'a> {
#diag
};
let param_ty = match builder.kind {
Some((SessionDiagnosticKind::Error, _)) => {
Some((DiagnosticDeriveKind::Error, _)) => {
quote! { rustc_errors::ErrorGuaranteed }
}
Some((SessionDiagnosticKind::Warn, _)) => quote! { () },
Some((DiagnosticDeriveKind::Lint | DiagnosticDeriveKind::Warn, _)) => {
quote! { () }
}
_ => unreachable!(),
};
@ -154,7 +105,7 @@ impl<'a> SessionDiagnosticDerive<'a> {
)
.emit();
let implementation = SessionDiagnosticDeriveError::ErrorHandled.to_compile_error();
let implementation = DiagnosticDeriveError::ErrorHandled.to_compile_error();
let param_ty = quote! { rustc_errors::ErrorGuaranteed };
(implementation, param_ty)
}
@ -176,523 +127,99 @@ impl<'a> SessionDiagnosticDerive<'a> {
}
}
/// What kind of session diagnostic is being derived - an error or a warning?
#[derive(Copy, Clone)]
enum SessionDiagnosticKind {
/// `#[error(..)]`
Error,
/// `#[warn(..)]`
Warn,
/// The central struct for constructing the `decorate_lint` method from an annotated struct.
pub(crate) struct LintDiagnosticDerive<'a> {
structure: Structure<'a>,
builder: DiagnosticDeriveBuilder,
}
impl SessionDiagnosticKind {
/// Returns human-readable string corresponding to the kind.
fn descr(&self) -> &'static str {
match self {
SessionDiagnosticKind::Error => "error",
SessionDiagnosticKind::Warn => "warning",
}
}
}
/// Tracks persistent information required for building up the individual calls to diagnostic
/// methods for the final generated method. This is a separate struct to `SessionDiagnosticDerive`
/// only to be able to destructure and split `self.builder` and the `self.structure` up to avoid a
/// double mut borrow later on.
struct SessionDiagnosticDeriveBuilder {
/// The identifier to use for the generated `DiagnosticBuilder` instance.
diag: syn::Ident,
/// Store a map of field name to its corresponding field. This is built on construction of the
/// derive builder.
fields: HashMap<String, TokenStream>,
/// Kind of diagnostic requested via the struct attribute.
kind: Option<(SessionDiagnosticKind, proc_macro::Span)>,
/// Slug is a mandatory part of the struct attribute as corresponds to the Fluent message that
/// has the actual diagnostic message.
slug: Option<(Path, proc_macro::Span)>,
/// Error codes are a optional part of the struct attribute - this is only set to detect
/// multiple specifications.
code: Option<(String, proc_macro::Span)>,
}
impl HasFieldMap for SessionDiagnosticDeriveBuilder {
fn get_field_binding(&self, field: &String) -> Option<&TokenStream> {
self.fields.get(field)
}
}
impl SessionDiagnosticDeriveBuilder {
/// Establishes state in the `SessionDiagnosticDeriveBuilder` resulting from the struct
/// attributes like `#[error(..)`, such as the diagnostic kind and slug. Generates
/// diagnostic builder calls for setting error code and creating note/help messages.
fn generate_structure_code(
&mut self,
attr: &Attribute,
) -> Result<TokenStream, SessionDiagnosticDeriveError> {
let diag = &self.diag;
let span = attr.span().unwrap();
let name = attr.path.segments.last().unwrap().ident.to_string();
let name = name.as_str();
let meta = attr.parse_meta()?;
let is_help_or_note = matches!(name, "help" | "note");
let nested = match meta {
// Most attributes are lists, like `#[error(..)]`/`#[warning(..)]` for most cases or
// `#[help(..)]`/`#[note(..)]` when the user is specifying a alternative slug.
Meta::List(MetaList { ref nested, .. }) => nested,
// Subdiagnostics without spans can be applied to the type too, and these are just
// paths: `#[help]` and `#[note]`
Meta::Path(_) if is_help_or_note => {
let fn_name = proc_macro2::Ident::new(name, attr.span());
return Ok(quote! { #diag.#fn_name(rustc_errors::fluent::_subdiag::#fn_name); });
}
_ => throw_invalid_attr!(attr, &meta),
};
// Check the kind before doing any further processing so that there aren't misleading
// "no kind specified" errors if there are failures later.
match name {
"error" => self.kind.set_once((SessionDiagnosticKind::Error, span)),
"warning" => self.kind.set_once((SessionDiagnosticKind::Warn, span)),
"help" | "note" => (),
_ => throw_invalid_attr!(attr, &meta, |diag| {
diag.help("only `error`, `warning`, `help` and `note` are valid attributes")
}),
}
// First nested element should always be the path, e.g. `#[error(typeck::invalid)]` or
// `#[help(typeck::another_help)]`.
let mut nested_iter = nested.into_iter();
if let Some(nested_attr) = nested_iter.next() {
// Report an error if there are any other list items after the path.
if is_help_or_note && nested_iter.next().is_some() {
throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
diag.help("`help` and `note` struct attributes can only have one argument")
});
}
match nested_attr {
NestedMeta::Meta(Meta::Path(path)) if is_help_or_note => {
let fn_name = proc_macro2::Ident::new(name, attr.span());
return Ok(quote! { #diag.#fn_name(rustc_errors::fluent::#path); });
}
NestedMeta::Meta(Meta::Path(path)) => {
self.slug.set_once((path.clone(), span));
}
NestedMeta::Meta(meta @ Meta::NameValue(_))
if !is_help_or_note
&& meta.path().segments.last().unwrap().ident.to_string() == "code" =>
{
// don't error for valid follow-up attributes
}
nested_attr => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
diag.help("first argument of the attribute should be the diagnostic slug")
}),
};
}
// Remaining attributes are optional, only `code = ".."` at the moment.
let mut tokens = Vec::new();
for nested_attr in nested_iter {
let meta = match nested_attr {
syn::NestedMeta::Meta(meta) => meta,
_ => throw_invalid_nested_attr!(attr, &nested_attr),
};
let path = meta.path();
let nested_name = path.segments.last().unwrap().ident.to_string();
// Struct attributes are only allowed to be applied once, and the diagnostic
// changes will be set in the initialisation code.
if let Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(s), .. }) = &meta {
let span = s.span().unwrap();
match nested_name.as_str() {
"code" => {
self.code.set_once((s.value(), span));
let code = &self.code.as_ref().map(|(v, _)| v);
tokens.push(quote! {
#diag.code(rustc_errors::DiagnosticId::Error(#code.to_string()));
});
}
_ => invalid_nested_attr(attr, &nested_attr)
.help("only `code` is a valid nested attributes following the slug")
.emit(),
}
} else {
invalid_nested_attr(attr, &nested_attr).emit()
}
}
Ok(tokens.drain(..).collect())
}
fn generate_field_attrs_code(&mut self, binding_info: &BindingInfo<'_>) -> TokenStream {
let field = binding_info.ast();
let field_binding = &binding_info.binding;
let inner_ty = FieldInnerTy::from_type(&field.ty);
// When generating `set_arg` or `add_subdiagnostic` calls, move data rather than
// borrow it to avoid requiring clones - this must therefore be the last use of
// each field (for example, any formatting machinery that might refer to a field
// should be generated already).
if field.attrs.is_empty() {
let diag = &self.diag;
let ident = field.ident.as_ref().unwrap();
quote! {
#diag.set_arg(
stringify!(#ident),
#field_binding
);
}
} else {
field
.attrs
.iter()
.map(move |attr| {
let name = attr.path.segments.last().unwrap().ident.to_string();
let (binding, needs_destructure) = match (name.as_str(), &inner_ty) {
// `primary_span` can accept a `Vec<Span>` so don't destructure that.
("primary_span", FieldInnerTy::Vec(_)) => {
(quote! { #field_binding.clone() }, false)
}
// `subdiagnostics` are not derefed because they are bound by value.
("subdiagnostic", _) => (quote! { #field_binding }, true),
_ => (quote! { *#field_binding }, true),
};
let generated_code = self
.generate_inner_field_code(
attr,
FieldInfo {
binding: binding_info,
ty: inner_ty.inner_type().unwrap_or(&field.ty),
span: &field.span(),
impl<'a> LintDiagnosticDerive<'a> {
pub(crate) fn new(diag: syn::Ident, structure: Structure<'a>) -> Self {
Self {
builder: DiagnosticDeriveBuilder {
diag,
fields: build_field_mapping(&structure),
kind: None,
code: None,
slug: None,
},
binding,
)
.unwrap_or_else(|v| v.to_compile_error());
structure,
}
}
if needs_destructure {
inner_ty.with(field_binding, generated_code)
pub(crate) fn into_tokens(self) -> TokenStream {
let LintDiagnosticDerive { mut structure, mut builder } = self;
let ast = structure.ast();
let implementation = {
if let syn::Data::Struct(..) = ast.data {
let preamble = builder.preamble(&structure);
let (attrs, args) = builder.body(&mut structure);
let diag = &builder.diag;
let span = ast.span().unwrap();
let init = match (builder.kind.value(), builder.slug.value()) {
(None, _) => {
span_err(span, "diagnostic kind not specified")
.help("use the `#[error(...)]` attribute to create an error")
.emit();
return DiagnosticDeriveError::ErrorHandled.to_compile_error();
}
(Some(kind), None) => {
span_err(span, "diagnostic slug not specified")
.help(&format!(
"specify the slug as the first argument to the attribute, such as \
`#[{}(typeck::example_error)]`",
kind.descr()
))
.emit();
return DiagnosticDeriveError::ErrorHandled.to_compile_error();
}
(Some(DiagnosticDeriveKind::Error | DiagnosticDeriveKind::Warn), _) => {
span_err(span, "only `#[lint(..)]` is supported")
.help("use the `#[lint(...)]` attribute to create a lint")
.emit();
return DiagnosticDeriveError::ErrorHandled.to_compile_error();
}
(Some(DiagnosticDeriveKind::Lint), Some(slug)) => {
quote! {
let mut #diag = #diag.build(rustc_errors::fluent::#slug);
}
}
};
let implementation = quote! {
#init
#preamble
match self {
#attrs
}
match self {
#args
}
#diag.emit();
};
implementation
} else {
generated_code
}
})
.collect()
}
}
fn generate_inner_field_code(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
binding: TokenStream,
) -> Result<TokenStream, SessionDiagnosticDeriveError> {
let meta = attr.parse_meta()?;
match meta {
Meta::Path(_) => self.generate_inner_field_code_path(attr, info, binding),
Meta::List(MetaList { .. }) => self.generate_inner_field_code_list(attr, info, binding),
_ => throw_invalid_attr!(attr, &meta),
}
}
fn generate_inner_field_code_path(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
binding: TokenStream,
) -> Result<TokenStream, SessionDiagnosticDeriveError> {
assert!(matches!(attr.parse_meta()?, Meta::Path(_)));
let diag = &self.diag;
let meta = attr.parse_meta()?;
let ident = &attr.path.segments.last().unwrap().ident;
let name = ident.to_string();
let name = name.as_str();
match name {
"skip_arg" => {
// Don't need to do anything - by virtue of the attribute existing, the
// `set_arg` call will not be generated.
Ok(quote! {})
}
"primary_span" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(quote! {
#diag.set_span(#binding);
})
}
"label" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(self.add_spanned_subdiagnostic(binding, ident, parse_quote! { _subdiag::label }))
}
"note" | "help" => {
let path = match name {
"note" => parse_quote! { _subdiag::note },
"help" => parse_quote! { _subdiag::help },
_ => unreachable!(),
};
if type_matches_path(&info.ty, &["rustc_span", "Span"]) {
Ok(self.add_spanned_subdiagnostic(binding, ident, path))
} else if type_is_unit(&info.ty) {
Ok(self.add_subdiagnostic(ident, path))
} else {
report_type_error(attr, "`Span` or `()`")?;
}
}
"subdiagnostic" => Ok(quote! { #diag.subdiagnostic(#binding); }),
_ => throw_invalid_attr!(attr, &meta, |diag| {
diag.help(
"only `skip_arg`, `primary_span`, `label`, `note`, `help` and `subdiagnostic` \
are valid field attributes",
)
}),
}
}
fn generate_inner_field_code_list(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
binding: TokenStream,
) -> Result<TokenStream, SessionDiagnosticDeriveError> {
let meta = attr.parse_meta()?;
let Meta::List(MetaList { ref path, ref nested, .. }) = meta else { unreachable!() };
let ident = &attr.path.segments.last().unwrap().ident;
let name = path.segments.last().unwrap().ident.to_string();
let name = name.as_ref();
match name {
"suggestion" | "suggestion_short" | "suggestion_hidden" | "suggestion_verbose" => {
return self.generate_inner_field_code_suggestion(attr, info);
}
"label" | "help" | "note" => (),
_ => throw_invalid_attr!(attr, &meta, |diag| {
diag.help(
"only `label`, `note`, `help` or `suggestion{,_short,_hidden,_verbose}` are \
valid field attributes",
)
}),
}
// For `#[label(..)]`, `#[note(..)]` and `#[help(..)]`, the first nested element must be a
// path, e.g. `#[label(typeck::label)]`.
let mut nested_iter = nested.into_iter();
let msg = match nested_iter.next() {
Some(NestedMeta::Meta(Meta::Path(path))) => path.clone(),
Some(nested_attr) => throw_invalid_nested_attr!(attr, &nested_attr),
None => throw_invalid_attr!(attr, &meta),
};
// None of these attributes should have anything following the slug.
if nested_iter.next().is_some() {
throw_invalid_attr!(attr, &meta);
}
match name {
"label" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(self.add_spanned_subdiagnostic(binding, ident, msg))
}
"note" | "help" if type_matches_path(&info.ty, &["rustc_span", "Span"]) => {
Ok(self.add_spanned_subdiagnostic(binding, ident, msg))
}
"note" | "help" if type_is_unit(&info.ty) => Ok(self.add_subdiagnostic(ident, msg)),
"note" | "help" => {
report_type_error(attr, "`Span` or `()`")?;
}
_ => unreachable!(),
}
}
fn generate_inner_field_code_suggestion(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
) -> Result<TokenStream, SessionDiagnosticDeriveError> {
let diag = &self.diag;
let mut meta = attr.parse_meta()?;
let Meta::List(MetaList { ref path, ref mut nested, .. }) = meta else { unreachable!() };
let (span_field, mut applicability) = self.span_and_applicability_of_ty(info)?;
let mut msg = None;
let mut code = None;
let mut nested_iter = nested.into_iter().peekable();
if let Some(nested_attr) = nested_iter.peek() {
if let NestedMeta::Meta(Meta::Path(path)) = nested_attr {
msg = Some(path.clone());
}
};
// Move the iterator forward if a path was found (don't otherwise so that
// code/applicability can be found or an error emitted).
if msg.is_some() {
let _ = nested_iter.next();
}
for nested_attr in nested_iter {
let meta = match nested_attr {
syn::NestedMeta::Meta(ref meta) => meta,
syn::NestedMeta::Lit(_) => throw_invalid_nested_attr!(attr, &nested_attr),
};
let nested_name = meta.path().segments.last().unwrap().ident.to_string();
let nested_name = nested_name.as_str();
match meta {
Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(s), .. }) => {
let span = meta.span().unwrap();
match nested_name {
"code" => {
let formatted_str = self.build_format(&s.value(), s.span());
code = Some(formatted_str);
}
"applicability" => {
applicability = match applicability {
Some(v) => {
span_err(
span,
"applicability cannot be set in both the field and \
attribute",
ast.span().unwrap(),
"`#[derive(LintDiagnostic)]` can only be used on structs",
)
.emit();
Some(v)
}
None => match Applicability::from_str(&s.value()) {
Ok(v) => Some(quote! { #v }),
Err(()) => {
span_err(span, "invalid applicability").emit();
None
}
},
}
}
_ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
diag.help(
"only `message`, `code` and `applicability` are valid field \
attributes",
)
}),
}
}
_ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
if matches!(meta, Meta::Path(_)) {
diag.help("a diagnostic slug must be the first argument to the attribute")
} else {
diag
}
}),
}
}
let applicability =
applicability.unwrap_or_else(|| quote!(rustc_errors::Applicability::Unspecified));
DiagnosticDeriveError::ErrorHandled.to_compile_error()
}
};
let name = path.segments.last().unwrap().ident.to_string();
let method = format_ident!("span_{}", name);
let msg = msg.unwrap_or_else(|| parse_quote! { _subdiag::suggestion });
let msg = quote! { rustc_errors::fluent::#msg };
let code = code.unwrap_or_else(|| quote! { String::new() });
Ok(quote! { #diag.#method(#span_field, #msg, #code, #applicability); })
}
/// Adds a spanned subdiagnostic by generating a `diag.span_$kind` call with the current slug
/// and `fluent_attr_identifier`.
fn add_spanned_subdiagnostic(
&self,
field_binding: TokenStream,
kind: &Ident,
fluent_attr_identifier: Path,
) -> TokenStream {
let diag = &self.diag;
let fn_name = format_ident!("span_{}", kind);
quote! {
#diag.#fn_name(
#field_binding,
rustc_errors::fluent::#fluent_attr_identifier
);
let diag = &builder.diag;
structure.gen_impl(quote! {
gen impl<'__a> rustc_errors::DecorateLint<'__a, ()> for @Self {
fn decorate_lint(self, #diag: rustc_errors::LintDiagnosticBuilder<'__a, ()>) {
use rustc_errors::IntoDiagnosticArg;
#implementation
}
}
/// Adds a subdiagnostic by generating a `diag.span_$kind` call with the current slug
/// and `fluent_attr_identifier`.
fn add_subdiagnostic(&self, kind: &Ident, fluent_attr_identifier: Path) -> TokenStream {
let diag = &self.diag;
quote! {
#diag.#kind(rustc_errors::fluent::#fluent_attr_identifier);
}
}
fn span_and_applicability_of_ty(
&self,
info: FieldInfo<'_>,
) -> Result<(TokenStream, Option<TokenStream>), SessionDiagnosticDeriveError> {
match &info.ty {
// If `ty` is `Span` w/out applicability, then use `Applicability::Unspecified`.
ty @ Type::Path(..) if type_matches_path(ty, &["rustc_span", "Span"]) => {
let binding = &info.binding.binding;
Ok((quote!(*#binding), None))
}
// If `ty` is `(Span, Applicability)` then return tokens accessing those.
Type::Tuple(tup) => {
let mut span_idx = None;
let mut applicability_idx = None;
for (idx, elem) in tup.elems.iter().enumerate() {
if type_matches_path(elem, &["rustc_span", "Span"]) {
if span_idx.is_none() {
span_idx = Some(syn::Index::from(idx));
} else {
throw_span_err!(
info.span.unwrap(),
"type of field annotated with `#[suggestion(...)]` contains more \
than one `Span`"
);
}
} else if type_matches_path(elem, &["rustc_errors", "Applicability"]) {
if applicability_idx.is_none() {
applicability_idx = Some(syn::Index::from(idx));
} else {
throw_span_err!(
info.span.unwrap(),
"type of field annotated with `#[suggestion(...)]` contains more \
than one Applicability"
);
}
}
}
if let Some(span_idx) = span_idx {
let binding = &info.binding.binding;
let span = quote!(#binding.#span_idx);
let applicability = applicability_idx
.map(|applicability_idx| quote!(#binding.#applicability_idx))
.unwrap_or_else(|| quote!(rustc_errors::Applicability::Unspecified));
return Ok((span, Some(applicability)));
}
throw_span_err!(info.span.unwrap(), "wrong types for suggestion", |diag| {
diag.help(
"`#[suggestion(...)]` on a tuple field must be applied to fields of type \
`(Span, Applicability)`",
)
});
}
// If `ty` isn't a `Span` or `(Span, Applicability)` then emit an error.
_ => throw_span_err!(info.span.unwrap(), "wrong field type for suggestion", |diag| {
diag.help(
"`#[suggestion(...)]` should be applied to fields of type `Span` or \
`(Span, Applicability)`",
)
}),
}
})
}
}

590
compiler/rustc_macros/src/diagnostics/diagnostic_builder.rs Normal file
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@ -0,0 +1,590 @@
#![deny(unused_must_use)]
use crate::diagnostics::error::{
invalid_nested_attr, span_err, throw_invalid_attr, throw_invalid_nested_attr, throw_span_err,
DiagnosticDeriveError,
};
use crate::diagnostics::utils::{
report_error_if_not_applied_to_span, report_type_error, type_is_unit, type_matches_path,
Applicability, FieldInfo, FieldInnerTy, HasFieldMap, SetOnce,
};
use proc_macro2::{Ident, TokenStream};
use quote::{format_ident, quote};
use std::collections::HashMap;
use std::str::FromStr;
use syn::{
parse_quote, spanned::Spanned, Attribute, Meta, MetaList, MetaNameValue, NestedMeta, Path, Type,
};
use synstructure::{BindingInfo, Structure};
/// What kind of diagnostic is being derived - an error, a warning or a lint?
#[derive(Copy, Clone)]
pub(crate) enum DiagnosticDeriveKind {
/// `#[error(..)]`
Error,
/// `#[warn(..)]`
Warn,
/// `#[lint(..)]`
Lint,
}
impl DiagnosticDeriveKind {
/// Returns human-readable string corresponding to the kind.
pub fn descr(&self) -> &'static str {
match self {
DiagnosticDeriveKind::Error => "error",
DiagnosticDeriveKind::Warn => "warning",
DiagnosticDeriveKind::Lint => "lint",
}
}
}
/// Tracks persistent information required for building up individual calls to diagnostic methods
/// for generated diagnostic derives - both `SessionDiagnostic` for errors/warnings and
/// `LintDiagnostic` for lints.
pub(crate) struct DiagnosticDeriveBuilder {
/// The identifier to use for the generated `DiagnosticBuilder` instance.
pub diag: syn::Ident,
/// Store a map of field name to its corresponding field. This is built on construction of the
/// derive builder.
pub fields: HashMap<String, TokenStream>,
/// Kind of diagnostic requested via the struct attribute.
pub kind: Option<(DiagnosticDeriveKind, proc_macro::Span)>,
/// Slug is a mandatory part of the struct attribute as corresponds to the Fluent message that
/// has the actual diagnostic message.
pub slug: Option<(Path, proc_macro::Span)>,
/// Error codes are a optional part of the struct attribute - this is only set to detect
/// multiple specifications.
pub code: Option<(String, proc_macro::Span)>,
}
impl HasFieldMap for DiagnosticDeriveBuilder {
fn get_field_binding(&self, field: &String) -> Option<&TokenStream> {
self.fields.get(field)
}
}
impl DiagnosticDeriveBuilder {
pub fn preamble<'s>(&mut self, structure: &Structure<'s>) -> TokenStream {
let ast = structure.ast();
let attrs = &ast.attrs;
let preamble = attrs.iter().map(|attr| {
self.generate_structure_code_for_attr(attr).unwrap_or_else(|v| v.to_compile_error())
});
quote! {
#(#preamble)*;
}
}
pub fn body<'s>(&mut self, structure: &mut Structure<'s>) -> (TokenStream, TokenStream) {
// Keep track of which fields are subdiagnostics or have no attributes.
let mut subdiagnostics_or_empty = std::collections::HashSet::new();
// Generates calls to `span_label` and similar functions based on the attributes
// on fields. Code for suggestions uses formatting machinery and the value of
// other fields - because any given field can be referenced multiple times, it
// should be accessed through a borrow. When passing fields to `add_subdiagnostic`
// or `set_arg` (which happens below) for Fluent, we want to move the data, so that
// has to happen in a separate pass over the fields.
let attrs = structure
.clone()
.filter(|field_binding| {
let attrs = &field_binding.ast().attrs;
(!attrs.is_empty()
&& attrs.iter().all(|attr| {
"subdiagnostic" != attr.path.segments.last().unwrap().ident.to_string()
}))
|| {
subdiagnostics_or_empty.insert(field_binding.binding.clone());
false
}
})
.each(|field_binding| self.generate_field_attrs_code(field_binding));
structure.bind_with(|_| synstructure::BindStyle::Move);
// When a field has attributes like `#[label]` or `#[note]` then it doesn't
// need to be passed as an argument to the diagnostic. But when a field has no
// attributes or a `#[subdiagnostic]` attribute then it must be passed as an
// argument to the diagnostic so that it can be referred to by Fluent messages.
let args = structure
.filter(|field_binding| subdiagnostics_or_empty.contains(&field_binding.binding))
.each(|field_binding| self.generate_field_attrs_code(field_binding));
(attrs, args)
}
/// Establishes state in the `DiagnosticDeriveBuilder` resulting from the struct
/// attributes like `#[error(..)`, such as the diagnostic kind and slug. Generates
/// diagnostic builder calls for setting error code and creating note/help messages.
fn generate_structure_code_for_attr(
&mut self,
attr: &Attribute,
) -> Result<TokenStream, DiagnosticDeriveError> {
let diag = &self.diag;
let span = attr.span().unwrap();
let name = attr.path.segments.last().unwrap().ident.to_string();
let name = name.as_str();
let meta = attr.parse_meta()?;
let is_help_or_note = matches!(name, "help" | "note");
let nested = match meta {
// Most attributes are lists, like `#[error(..)]`/`#[warning(..)]` for most cases or
// `#[help(..)]`/`#[note(..)]` when the user is specifying a alternative slug.
Meta::List(MetaList { ref nested, .. }) => nested,
// Subdiagnostics without spans can be applied to the type too, and these are just
// paths: `#[help]` and `#[note]`
Meta::Path(_) if is_help_or_note => {
let fn_name = proc_macro2::Ident::new(name, attr.span());
return Ok(quote! { #diag.#fn_name(rustc_errors::fluent::_subdiag::#fn_name); });
}
_ => throw_invalid_attr!(attr, &meta),
};
// Check the kind before doing any further processing so that there aren't misleading
// "no kind specified" errors if there are failures later.
match name {
"error" => self.kind.set_once((DiagnosticDeriveKind::Error, span)),
"warning" => self.kind.set_once((DiagnosticDeriveKind::Warn, span)),
"lint" => self.kind.set_once((DiagnosticDeriveKind::Lint, span)),
"help" | "note" => (),
_ => throw_invalid_attr!(attr, &meta, |diag| {
diag.help("only `error`, `warning`, `help` and `note` are valid attributes")
}),
}
// First nested element should always be the path, e.g. `#[error(typeck::invalid)]` or
// `#[help(typeck::another_help)]`.
let mut nested_iter = nested.into_iter();
if let Some(nested_attr) = nested_iter.next() {
// Report an error if there are any other list items after the path.
if is_help_or_note && nested_iter.next().is_some() {
throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
diag.help("`help` and `note` struct attributes can only have one argument")
});
}
match nested_attr {
NestedMeta::Meta(Meta::Path(path)) if is_help_or_note => {
let fn_name = proc_macro2::Ident::new(name, attr.span());
return Ok(quote! { #diag.#fn_name(rustc_errors::fluent::#path); });
}
NestedMeta::Meta(Meta::Path(path)) => {
self.slug.set_once((path.clone(), span));
}
NestedMeta::Meta(meta @ Meta::NameValue(_))
if !is_help_or_note
&& meta.path().segments.last().unwrap().ident.to_string() == "code" =>
{
// don't error for valid follow-up attributes
}
nested_attr => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
diag.help("first argument of the attribute should be the diagnostic slug")
}),
};
}
// Remaining attributes are optional, only `code = ".."` at the moment.
let mut tokens = Vec::new();
for nested_attr in nested_iter {
let meta = match nested_attr {
syn::NestedMeta::Meta(meta) => meta,
_ => throw_invalid_nested_attr!(attr, &nested_attr),
};
let path = meta.path();
let nested_name = path.segments.last().unwrap().ident.to_string();
// Struct attributes are only allowed to be applied once, and the diagnostic
// changes will be set in the initialisation code.
if let Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(s), .. }) = &meta {
let span = s.span().unwrap();
match nested_name.as_str() {
"code" => {
self.code.set_once((s.value(), span));
let code = &self.code.as_ref().map(|(v, _)| v);
tokens.push(quote! {
#diag.code(rustc_errors::DiagnosticId::Error(#code.to_string()));
});
}
_ => invalid_nested_attr(attr, &nested_attr)
.help("only `code` is a valid nested attributes following the slug")
.emit(),
}
} else {
invalid_nested_attr(attr, &nested_attr).emit()
}
}
Ok(tokens.drain(..).collect())
}
fn generate_field_attrs_code(&mut self, binding_info: &BindingInfo<'_>) -> TokenStream {
let field = binding_info.ast();
let field_binding = &binding_info.binding;
let inner_ty = FieldInnerTy::from_type(&field.ty);
// When generating `set_arg` or `add_subdiagnostic` calls, move data rather than
// borrow it to avoid requiring clones - this must therefore be the last use of
// each field (for example, any formatting machinery that might refer to a field
// should be generated already).
if field.attrs.is_empty() {
let diag = &self.diag;
let ident = field.ident.as_ref().unwrap();
quote! {
#diag.set_arg(
stringify!(#ident),
#field_binding
);
}
} else {
field
.attrs
.iter()
.map(move |attr| {
let name = attr.path.segments.last().unwrap().ident.to_string();
let (binding, needs_destructure) = match (name.as_str(), &inner_ty) {
// `primary_span` can accept a `Vec<Span>` so don't destructure that.
("primary_span", FieldInnerTy::Vec(_)) => {
(quote! { #field_binding.clone() }, false)
}
// `subdiagnostics` are not derefed because they are bound by value.
("subdiagnostic", _) => (quote! { #field_binding }, true),
_ => (quote! { *#field_binding }, true),
};
let generated_code = self
.generate_inner_field_code(
attr,
FieldInfo {
binding: binding_info,
ty: inner_ty.inner_type().unwrap_or(&field.ty),
span: &field.span(),
},
binding,
)
.unwrap_or_else(|v| v.to_compile_error());
if needs_destructure {
inner_ty.with(field_binding, generated_code)
} else {
generated_code
}
})
.collect()
}
}
fn generate_inner_field_code(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
binding: TokenStream,
) -> Result<TokenStream, DiagnosticDeriveError> {
let meta = attr.parse_meta()?;
match meta {
Meta::Path(_) => self.generate_inner_field_code_path(attr, info, binding),
Meta::List(MetaList { .. }) => self.generate_inner_field_code_list(attr, info, binding),
_ => throw_invalid_attr!(attr, &meta),
}
}
fn generate_inner_field_code_path(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
binding: TokenStream,
) -> Result<TokenStream, DiagnosticDeriveError> {
assert!(matches!(attr.parse_meta()?, Meta::Path(_)));
let diag = &self.diag;
let meta = attr.parse_meta()?;
let ident = &attr.path.segments.last().unwrap().ident;
let name = ident.to_string();
let name = name.as_str();
match name {
"skip_arg" => {
// Don't need to do anything - by virtue of the attribute existing, the
// `set_arg` call will not be generated.
Ok(quote! {})
}
"primary_span" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(quote! {
#diag.set_span(#binding);
})
}
"label" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(self.add_spanned_subdiagnostic(binding, ident, parse_quote! { _subdiag::label }))
}
"note" | "help" => {
let path = match name {
"note" => parse_quote! { _subdiag::note },
"help" => parse_quote! { _subdiag::help },
_ => unreachable!(),
};
if type_matches_path(&info.ty, &["rustc_span", "Span"]) {
Ok(self.add_spanned_subdiagnostic(binding, ident, path))
} else if type_is_unit(&info.ty) {
Ok(self.add_subdiagnostic(ident, path))
} else {
report_type_error(attr, "`Span` or `()`")?
}
}
"subdiagnostic" => Ok(quote! { #diag.subdiagnostic(#binding); }),
_ => throw_invalid_attr!(attr, &meta, |diag| {
diag.help(
"only `skip_arg`, `primary_span`, `label`, `note`, `help` and `subdiagnostic` \
are valid field attributes",
)
}),
}
}
fn generate_inner_field_code_list(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
binding: TokenStream,
) -> Result<TokenStream, DiagnosticDeriveError> {
let meta = attr.parse_meta()?;
let Meta::List(MetaList { ref path, ref nested, .. }) = meta else { unreachable!() };
let ident = &attr.path.segments.last().unwrap().ident;
let name = path.segments.last().unwrap().ident.to_string();
let name = name.as_ref();
match name {
"suggestion" | "suggestion_short" | "suggestion_hidden" | "suggestion_verbose" => {
return self.generate_inner_field_code_suggestion(attr, info);
}
"label" | "help" | "note" => (),
_ => throw_invalid_attr!(attr, &meta, |diag| {
diag.help(
"only `label`, `note`, `help` or `suggestion{,_short,_hidden,_verbose}` are \
valid field attributes",
)
}),
}
// For `#[label(..)]`, `#[note(..)]` and `#[help(..)]`, the first nested element must be a
// path, e.g. `#[label(typeck::label)]`.
let mut nested_iter = nested.into_iter();
let msg = match nested_iter.next() {
Some(NestedMeta::Meta(Meta::Path(path))) => path.clone(),
Some(nested_attr) => throw_invalid_nested_attr!(attr, &nested_attr),
None => throw_invalid_attr!(attr, &meta),
};
// None of these attributes should have anything following the slug.
if nested_iter.next().is_some() {
throw_invalid_attr!(attr, &meta);
}
match name {
"label" => {
report_error_if_not_applied_to_span(attr, &info)?;
Ok(self.add_spanned_subdiagnostic(binding, ident, msg))
}
"note" | "help" if type_matches_path(&info.ty, &["rustc_span", "Span"]) => {
Ok(self.add_spanned_subdiagnostic(binding, ident, msg))
}
"note" | "help" if type_is_unit(&info.ty) => Ok(self.add_subdiagnostic(ident, msg)),
"note" | "help" => report_type_error(attr, "`Span` or `()`")?,
_ => unreachable!(),
}
}
fn generate_inner_field_code_suggestion(
&mut self,
attr: &Attribute,
info: FieldInfo<'_>,
) -> Result<TokenStream, DiagnosticDeriveError> {
let diag = &self.diag;
let mut meta = attr.parse_meta()?;
let Meta::List(MetaList { ref path, ref mut nested, .. }) = meta else { unreachable!() };
let (span_field, mut applicability) = self.span_and_applicability_of_ty(info)?;
let mut msg = None;
let mut code = None;
let mut nested_iter = nested.into_iter().peekable();
if let Some(nested_attr) = nested_iter.peek() {
if let NestedMeta::Meta(Meta::Path(path)) = nested_attr {
msg = Some(path.clone());
}
};
// Move the iterator forward if a path was found (don't otherwise so that
// code/applicability can be found or an error emitted).
if msg.is_some() {
let _ = nested_iter.next();
}
for nested_attr in nested_iter {
let meta = match nested_attr {
syn::NestedMeta::Meta(ref meta) => meta,
syn::NestedMeta::Lit(_) => throw_invalid_nested_attr!(attr, &nested_attr),
};
let nested_name = meta.path().segments.last().unwrap().ident.to_string();
let nested_name = nested_name.as_str();
match meta {
Meta::NameValue(MetaNameValue { lit: syn::Lit::Str(s), .. }) => {
let span = meta.span().unwrap();
match nested_name {
"code" => {
let formatted_str = self.build_format(&s.value(), s.span());
code = Some(formatted_str);
}
"applicability" => {
applicability = match applicability {
Some(v) => {
span_err(
span,
"applicability cannot be set in both the field and \
attribute",
)
.emit();
Some(v)
}
None => match Applicability::from_str(&s.value()) {
Ok(v) => Some(quote! { #v }),
Err(()) => {
span_err(span, "invalid applicability").emit();
None
}
},
}
}
_ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
diag.help(
"only `message`, `code` and `applicability` are valid field \
attributes",
)
}),
}
}
_ => throw_invalid_nested_attr!(attr, &nested_attr, |diag| {
if matches!(meta, Meta::Path(_)) {
diag.help("a diagnostic slug must be the first argument to the attribute")
} else {
diag
}
}),
}
}
let applicability =
applicability.unwrap_or_else(|| quote!(rustc_errors::Applicability::Unspecified));
let name = path.segments.last().unwrap().ident.to_string();
let method = format_ident!("span_{}", name);
let msg = msg.unwrap_or_else(|| parse_quote! { _subdiag::suggestion });
let msg = quote! { rustc_errors::fluent::#msg };
let code = code.unwrap_or_else(|| quote! { String::new() });
Ok(quote! { #diag.#method(#span_field, #msg, #code, #applicability); })
}
/// Adds a spanned subdiagnostic by generating a `diag.span_$kind` call with the current slug
/// and `fluent_attr_identifier`.
fn add_spanned_subdiagnostic(
&self,
field_binding: TokenStream,
kind: &Ident,
fluent_attr_identifier: Path,
) -> TokenStream {
let diag = &self.diag;
let fn_name = format_ident!("span_{}", kind);
quote! {
#diag.#fn_name(
#field_binding,
rustc_errors::fluent::#fluent_attr_identifier
);
}
}
/// Adds a subdiagnostic by generating a `diag.span_$kind` call with the current slug
/// and `fluent_attr_identifier`.
fn add_subdiagnostic(&self, kind: &Ident, fluent_attr_identifier: Path) -> TokenStream {
let diag = &self.diag;
quote! {
#diag.#kind(rustc_errors::fluent::#fluent_attr_identifier);
}
}
fn span_and_applicability_of_ty(
&self,
info: FieldInfo<'_>,
) -> Result<(TokenStream, Option<TokenStream>), DiagnosticDeriveError> {
match &info.ty {
// If `ty` is `Span` w/out applicability, then use `Applicability::Unspecified`.
ty @ Type::Path(..) if type_matches_path(ty, &["rustc_span", "Span"]) => {
let binding = &info.binding.binding;
Ok((quote!(*#binding), None))
}
// If `ty` is `(Span, Applicability)` then return tokens accessing those.
Type::Tuple(tup) => {
let mut span_idx = None;
let mut applicability_idx = None;
for (idx, elem) in tup.elems.iter().enumerate() {
if type_matches_path(elem, &["rustc_span", "Span"]) {
if span_idx.is_none() {
span_idx = Some(syn::Index::from(idx));
} else {
throw_span_err!(
info.span.unwrap(),
"type of field annotated with `#[suggestion(...)]` contains more \
than one `Span`"
);
}
} else if type_matches_path(elem, &["rustc_errors", "Applicability"]) {
if applicability_idx.is_none() {
applicability_idx = Some(syn::Index::from(idx));
} else {
throw_span_err!(
info.span.unwrap(),
"type of field annotated with `#[suggestion(...)]` contains more \
than one Applicability"
);
}
}
}
if let Some(span_idx) = span_idx {
let binding = &info.binding.binding;
let span = quote!(#binding.#span_idx);
let applicability = applicability_idx
.map(|applicability_idx| quote!(#binding.#applicability_idx))
.unwrap_or_else(|| quote!(rustc_errors::Applicability::Unspecified));
return Ok((span, Some(applicability)));
}
throw_span_err!(info.span.unwrap(), "wrong types for suggestion", |diag| {
diag.help(
"`#[suggestion(...)]` on a tuple field must be applied to fields of type \
`(Span, Applicability)`",
)
});
}
// If `ty` isn't a `Span` or `(Span, Applicability)` then emit an error.
_ => throw_span_err!(info.span.unwrap(), "wrong field type for suggestion", |diag| {
diag.help(
"`#[suggestion(...)]` should be applied to fields of type `Span` or \
`(Span, Applicability)`",
)
}),
}
}
}

22
compiler/rustc_macros/src/diagnostics/error.rs
View File

@ -4,16 +4,16 @@ use quote::quote;
use syn::{spanned::Spanned, Attribute, Error as SynError, Meta, NestedMeta};
#[derive(Debug)]
pub(crate) enum SessionDiagnosticDeriveError {
pub(crate) enum DiagnosticDeriveError {
SynError(SynError),
ErrorHandled,
}
impl SessionDiagnosticDeriveError {
impl DiagnosticDeriveError {
pub(crate) fn to_compile_error(self) -> TokenStream {
match self {
SessionDiagnosticDeriveError::SynError(e) => e.to_compile_error(),
SessionDiagnosticDeriveError::ErrorHandled => {
DiagnosticDeriveError::SynError(e) => e.to_compile_error(),
DiagnosticDeriveError::ErrorHandled => {
// Return ! to avoid having to create a blank DiagnosticBuilder to return when an
// error has already been emitted to the compiler.
quote! {
@ -24,9 +24,9 @@ impl SessionDiagnosticDeriveError {
}
}
impl From<SynError> for SessionDiagnosticDeriveError {
impl From<SynError> for DiagnosticDeriveError {
fn from(e: SynError) -> Self {
SessionDiagnosticDeriveError::SynError(e)
DiagnosticDeriveError::SynError(e)
}
}
@ -34,9 +34,9 @@ impl From<SynError> for SessionDiagnosticDeriveError {
pub(crate) fn _throw_err(
diag: Diagnostic,
f: impl FnOnce(Diagnostic) -> Diagnostic,
) -> SessionDiagnosticDeriveError {
) -> DiagnosticDeriveError {
f(diag).emit();
SessionDiagnosticDeriveError::ErrorHandled
DiagnosticDeriveError::ErrorHandled
}
/// Helper function for printing `syn::Path` - doesn't handle arguments in paths and these are
@ -60,7 +60,7 @@ pub(crate) fn span_err(span: impl MultiSpan, msg: &str) -> Diagnostic {
/// Emit a diagnostic on span `$span` with msg `$msg` (optionally performing additional decoration
/// using the `FnOnce` passed in `diag`) and return `Err(ErrorHandled)`.
///
/// For methods that return a `Result<_, SessionDiagnosticDeriveError>`:
/// For methods that return a `Result<_, DiagnosticDeriveError>`:
macro_rules! throw_span_err {
($span:expr, $msg:expr) => {{ throw_span_err!($span, $msg, |diag| diag) }};
($span:expr, $msg:expr, $f:expr) => {{
@ -87,7 +87,7 @@ pub(crate) fn invalid_attr(attr: &Attribute, meta: &Meta) -> Diagnostic {
/// Emit a error diagnostic for an invalid attribute (optionally performing additional decoration
/// using the `FnOnce` passed in `diag`) and return `Err(ErrorHandled)`.
///
/// For methods that return a `Result<_, SessionDiagnosticDeriveError>`:
/// For methods that return a `Result<_, DiagnosticDeriveError>`:
macro_rules! throw_invalid_attr {
($attr:expr, $meta:expr) => {{ throw_invalid_attr!($attr, $meta, |diag| diag) }};
($attr:expr, $meta:expr, $f:expr) => {{
@ -129,7 +129,7 @@ pub(crate) fn invalid_nested_attr(attr: &Attribute, nested: &NestedMeta) -> Diag
/// Emit a error diagnostic for an invalid nested attribute (optionally performing additional
/// decoration using the `FnOnce` passed in `diag`) and return `Err(ErrorHandled)`.
///
/// For methods that return a `Result<_, SessionDiagnosticDeriveError>`:
/// For methods that return a `Result<_, DiagnosticDeriveError>`:
macro_rules! throw_invalid_nested_attr {
($attr:expr, $nested_attr:expr) => {{ throw_invalid_nested_attr!($attr, $nested_attr, |diag| diag) }};
($attr:expr, $nested_attr:expr, $f:expr) => {{

53
compiler/rustc_macros/src/diagnostics/mod.rs
View File

@ -1,10 +1,11 @@
mod diagnostic;
mod diagnostic_builder;
mod error;
mod fluent;
mod subdiagnostic;
mod utils;
use diagnostic::SessionDiagnosticDerive;
use diagnostic::{LintDiagnosticDerive, SessionDiagnosticDerive};
pub(crate) use fluent::fluent_messages;
use proc_macro2::TokenStream;
use quote::format_ident;
@ -58,11 +59,53 @@ use synstructure::Structure;
/// See rustc dev guide for more examples on using the `#[derive(SessionDiagnostic)]`:
/// <https://rustc-dev-guide.rust-lang.org/diagnostics/diagnostic-structs.html>
pub fn session_diagnostic_derive(s: Structure<'_>) -> TokenStream {
// Names for the diagnostic we build and the session we build it from.
let diag = format_ident!("diag");
let sess = format_ident!("sess");
SessionDiagnosticDerive::new(format_ident!("diag"), format_ident!("sess"), s).into_tokens()
}
SessionDiagnosticDerive::new(diag, sess, s).into_tokens()
/// Implements `#[derive(LintDiagnostic)]`, which allows for lints to be specified as a struct,
/// independent from the actual lint emitting code.
///
/// ```ignore (rust)
/// #[derive(LintDiagnostic)]
/// #[lint(lint::atomic_ordering_invalid_fail_success)]
/// pub struct AtomicOrderingInvalidLint {
/// method: Symbol,
/// success_ordering: Symbol,
/// fail_ordering: Symbol,
/// #[label(lint::fail_label)]
/// fail_order_arg_span: Span,
/// #[label(lint::success_label)]
/// #[suggestion(
/// code = "std::sync::atomic::Ordering::{success_suggestion}",
/// applicability = "maybe-incorrect"
/// )]
/// success_order_arg_span: Span,
/// }
/// ```
///
/// ```fluent
/// lint-atomic-ordering-invalid-fail-success = `{$method}`'s success ordering must be at least as strong as its failure ordering
/// .fail-label = `{$fail_ordering}` failure ordering
/// .success-label = `{$success_ordering}` success ordering
/// .suggestion = consider using `{$success_suggestion}` success ordering instead
/// ```
///
/// Then, later, to emit the error:
///
/// ```ignore (rust)
/// cx.struct_span_lint(INVALID_ATOMIC_ORDERING, fail_order_arg_span, AtomicOrderingInvalidLint {
/// method,
/// success_ordering,
/// fail_ordering,
/// fail_order_arg_span,
/// success_order_arg_span,
/// });
/// ```
///
/// See rustc dev guide for more examples on using the `#[derive(LintDiagnostic)]`:
/// <https://rustc-dev-guide.rust-lang.org/diagnostics/sessiondiagnostic.html>
pub fn lint_diagnostic_derive(s: Structure<'_>) -> TokenStream {
LintDiagnosticDerive::new(format_ident!("diag"), s).into_tokens()
}
/// Implements `#[derive(SessionSubdiagnostic)]`, which allows for labels, notes, helps and

9
compiler/rustc_macros/src/diagnostics/subdiagnostic.rs
View File

@ -1,8 +1,7 @@
#![deny(unused_must_use)]
use crate::diagnostics::error::{
span_err, throw_invalid_attr, throw_invalid_nested_attr, throw_span_err,
SessionDiagnosticDeriveError,
span_err, throw_invalid_attr, throw_invalid_nested_attr, throw_span_err, DiagnosticDeriveError,
};
use crate::diagnostics::utils::{
report_error_if_not_applied_to_applicability, report_error_if_not_applied_to_span,
@ -214,7 +213,7 @@ impl<'a> HasFieldMap for SessionSubdiagnosticDeriveBuilder<'a> {
}
impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
fn identify_kind(&mut self) -> Result<(), SessionDiagnosticDeriveError> {
fn identify_kind(&mut self) -> Result<(), DiagnosticDeriveError> {
for attr in self.variant.ast().attrs {
let span = attr.span().unwrap();
@ -351,7 +350,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
&mut self,
binding: &BindingInfo<'_>,
is_suggestion: bool,
) -> Result<TokenStream, SessionDiagnosticDeriveError> {
) -> Result<TokenStream, DiagnosticDeriveError> {
let ast = binding.ast();
let inner_ty = FieldInnerTy::from_type(&ast.ty);
@ -411,7 +410,7 @@ impl<'a> SessionSubdiagnosticDeriveBuilder<'a> {
Ok(inner_ty.with(binding, generated))
}
fn into_tokens(&mut self) -> Result<TokenStream, SessionDiagnosticDeriveError> {
fn into_tokens(&mut self) -> Result<TokenStream, DiagnosticDeriveError> {
self.identify_kind()?;
let Some(kind) = self.kind.map(|(kind, _)| kind) else {
throw_span_err!(

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 {

19
compiler/rustc_macros/src/lib.rs
View File

@ -127,6 +127,7 @@ decl_derive!(
// struct attributes
warning,
error,
lint,
note,
help,
// field attributes
@ -139,6 +140,24 @@ decl_derive!(
suggestion_hidden,
suggestion_verbose)] => diagnostics::session_diagnostic_derive
);
decl_derive!(
[LintDiagnostic, attributes(
// struct attributes
warning,
error,
lint,
note,
help,
// field attributes
skip_arg,
primary_span,
label,
subdiagnostic,
suggestion,
suggestion_short,
suggestion_hidden,
suggestion_verbose)] => diagnostics::lint_diagnostic_derive
);
decl_derive!(
[SessionSubdiagnostic, attributes(
// struct/variant attributes

19
src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
View File

@ -17,7 +17,7 @@ use rustc_span::symbol::Ident;
use rustc_span::Span;
extern crate rustc_macros;
use rustc_macros::{SessionDiagnostic, SessionSubdiagnostic};
use rustc_macros::{SessionDiagnostic, LintDiagnostic, SessionSubdiagnostic};
extern crate rustc_middle;
use rustc_middle::ty::Ty;
@ -535,3 +535,20 @@ struct LabelWithTrailingList {
//~^ ERROR `#[label(...)]` is not a valid attribute
span: Span,
}
#[derive(SessionDiagnostic)]
#[lint(typeck::ambiguous_lifetime_bound)]
//~^ ERROR only `#[error(..)]` and `#[warn(..)]` are supported
struct LintsBad {
}
#[derive(LintDiagnostic)]
#[lint(typeck::ambiguous_lifetime_bound)]
struct LintsGood {
}
#[derive(LintDiagnostic)]
#[error(typeck::ambiguous_lifetime_bound)]
//~^ ERROR only `#[lint(..)]` is supported
struct ErrorsBad {
}

24
src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
View File

@ -363,6 +363,28 @@ error: `#[label(...)]` is not a valid attribute
LL | #[label(typeck::label, foo("..."))]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
error: only `#[error(..)]` and `#[warn(..)]` are supported
--> $DIR/diagnostic-derive.rs:540:1
|
LL | / #[lint(typeck::ambiguous_lifetime_bound)]
LL | |
LL | | struct LintsBad {
LL | | }
| |_^
|
= help: use the `#[error(...)]` attribute to create a error
error: only `#[lint(..)]` is supported
--> $DIR/diagnostic-derive.rs:551:1
|
LL | / #[error(typeck::ambiguous_lifetime_bound)]
LL | |
LL | | struct ErrorsBad {
LL | | }
| |_^
|
= help: use the `#[lint(...)]` attribute to create a lint
error: cannot find attribute `nonsense` in this scope
--> $DIR/diagnostic-derive.rs:53:3
|
@ -395,7 +417,7 @@ LL | arg: impl IntoDiagnosticArg,
| ^^^^^^^^^^^^^^^^^ required by this bound in `DiagnosticBuilder::<'a, G>::set_arg`
= note: this error originates in the derive macro `SessionDiagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
error: aborting due to 46 previous errors
error: aborting due to 48 previous errors
Some errors have detailed explanations: E0277, E0425.
For more information about an error, try `rustc --explain E0277`.