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Lint missing Abi in ast validation instead of lowering. #87114

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merged 1 commit into from
Sep 2, 2021
Merged

Lint missing Abi in ast validation instead of lowering. #87114

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1 change: 1 addition & 0 deletions Cargo.lock
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Original file line number Diff line number Diff line change
Expand Up @@ -3556,6 +3556,7 @@ dependencies = [
"rustc_parse",
"rustc_session",
"rustc_span",
"rustc_target",
"tracing",
]

Expand Down
37 changes: 13 additions & 24 deletions compiler/rustc_ast_lowering/src/item.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -283,7 +283,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
);
let sig = hir::FnSig {
decl,
header: this.lower_fn_header(header, fn_sig_span, id),
header: this.lower_fn_header(header),
span: this.lower_span(fn_sig_span),
};
hir::ItemKind::Fn(sig, generics, body_id)
Expand All @@ -295,17 +295,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
}
ModKind::Unloaded => panic!("`mod` items should have been loaded by now"),
},
ItemKind::ForeignMod(ref fm) => {
if fm.abi.is_none() {
self.maybe_lint_missing_abi(span, id, abi::Abi::C { unwind: false });
}
hir::ItemKind::ForeignMod {
abi: fm.abi.map_or(abi::Abi::C { unwind: false }, |abi| self.lower_abi(abi)),
items: self
.arena
.alloc_from_iter(fm.items.iter().map(|x| self.lower_foreign_item_ref(x))),
}
}
ItemKind::ForeignMod(ref fm) => hir::ItemKind::ForeignMod {
abi: fm.abi.map_or(abi::Abi::FALLBACK, |abi| self.lower_abi(abi)),
items: self
.arena
.alloc_from_iter(fm.items.iter().map(|x| self.lower_foreign_item_ref(x))),
},
ItemKind::GlobalAsm(ref asm) => {
hir::ItemKind::GlobalAsm(self.lower_inline_asm(span, asm))
}
Expand Down Expand Up @@ -811,7 +806,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
AssocItemKind::Fn(box FnKind(_, ref sig, ref generics, None)) => {
let names = self.lower_fn_params_to_names(&sig.decl);
let (generics, sig) =
self.lower_method_sig(generics, sig, trait_item_def_id, false, None, i.id);
self.lower_method_sig(generics, sig, trait_item_def_id, false, None);
(generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Required(names)))
}
AssocItemKind::Fn(box FnKind(_, ref sig, ref generics, Some(ref body))) => {
Expand All @@ -824,7 +819,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
trait_item_def_id,
false,
asyncness.opt_return_id(),
i.id,
);
(generics, hir::TraitItemKind::Fn(sig, hir::TraitFn::Provided(body_id)))
}
Expand Down Expand Up @@ -901,7 +895,6 @@ impl<'hir> LoweringContext<'_, 'hir> {
impl_item_def_id,
impl_trait_return_allow,
asyncness.opt_return_id(),
i.id,
);

(generics, hir::ImplItemKind::Fn(sig, body_id))
Expand Down Expand Up @@ -1296,9 +1289,8 @@ impl<'hir> LoweringContext<'_, 'hir> {
fn_def_id: LocalDefId,
impl_trait_return_allow: bool,
is_async: Option<NodeId>,
id: NodeId,
) -> (hir::Generics<'hir>, hir::FnSig<'hir>) {
let header = self.lower_fn_header(sig.header, sig.span, id);
let header = self.lower_fn_header(sig.header);
let (generics, decl) = self.add_in_band_defs(
generics,
fn_def_id,
Expand All @@ -1315,12 +1307,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
(generics, hir::FnSig { header, decl, span: self.lower_span(sig.span) })
}

fn lower_fn_header(&mut self, h: FnHeader, span: Span, id: NodeId) -> hir::FnHeader {
fn lower_fn_header(&mut self, h: FnHeader) -> hir::FnHeader {
hir::FnHeader {
unsafety: self.lower_unsafety(h.unsafety),
asyncness: self.lower_asyncness(h.asyncness),
constness: self.lower_constness(h.constness),
abi: self.lower_extern(h.ext, span, id),
abi: self.lower_extern(h.ext),
}
}

Expand All @@ -1331,13 +1323,10 @@ impl<'hir> LoweringContext<'_, 'hir> {
})
}

pub(super) fn lower_extern(&mut self, ext: Extern, span: Span, id: NodeId) -> abi::Abi {
pub(super) fn lower_extern(&mut self, ext: Extern) -> abi::Abi {
match ext {
Extern::None => abi::Abi::Rust,
Extern::Implicit => {
self.maybe_lint_missing_abi(span, id, abi::Abi::C { unwind: false });
abi::Abi::C { unwind: false }
}
Extern::Implicit => abi::Abi::FALLBACK,
Extern::Explicit(abi) => self.lower_abi(abi),
}
}
Expand Down
26 changes: 2 additions & 24 deletions compiler/rustc_ast_lowering/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -53,7 +53,7 @@ use rustc_hir::definitions::{DefKey, DefPathData, Definitions};
use rustc_hir::intravisit;
use rustc_hir::{ConstArg, GenericArg, InferKind, ParamName};
use rustc_index::vec::{Idx, IndexVec};
use rustc_session::lint::builtin::{BARE_TRAIT_OBJECTS, MISSING_ABI};
use rustc_session::lint::builtin::BARE_TRAIT_OBJECTS;
use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
use rustc_session::utils::{FlattenNonterminals, NtToTokenstream};
use rustc_session::Session;
Expand All @@ -62,7 +62,6 @@ use rustc_span::hygiene::ExpnId;
use rustc_span::source_map::{respan, CachingSourceMapView, DesugaringKind};
use rustc_span::symbol::{kw, sym, Ident, Symbol};
use rustc_span::{Span, DUMMY_SP};
use rustc_target::spec::abi::Abi;

use smallvec::{smallvec, SmallVec};
use std::collections::BTreeMap;
Expand Down Expand Up @@ -1360,15 +1359,14 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
TyKind::BareFn(ref f) => self.with_in_scope_lifetime_defs(&f.generic_params, |this| {
this.with_anonymous_lifetime_mode(AnonymousLifetimeMode::PassThrough, |this| {
let span = this.sess.source_map().next_point(t.span.shrink_to_lo());
hir::TyKind::BareFn(this.arena.alloc(hir::BareFnTy {
generic_params: this.lower_generic_params(
&f.generic_params,
&NodeMap::default(),
ImplTraitContext::disallowed(),
),
unsafety: this.lower_unsafety(f.unsafety),
abi: this.lower_extern(f.ext, span, t.id),
abi: this.lower_extern(f.ext),
decl: this.lower_fn_decl(&f.decl, None, false, None),
param_names: this.lower_fn_params_to_names(&f.decl),
}))
Expand Down Expand Up @@ -2842,26 +2840,6 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
}
}
}

fn maybe_lint_missing_abi(&mut self, span: Span, id: NodeId, default: Abi) {
// FIXME(davidtwco): This is a hack to detect macros which produce spans of the
// call site which do not have a macro backtrace. See #61963.
let is_macro_callsite = self
.sess
.source_map()
.span_to_snippet(span)
.map(|snippet| snippet.starts_with("#["))
.unwrap_or(true);
if !is_macro_callsite {
self.resolver.lint_buffer().buffer_lint_with_diagnostic(
MISSING_ABI,
id,
span,
"extern declarations without an explicit ABI are deprecated",
BuiltinLintDiagnostics::MissingAbi(span, default),
)
}
}
}

fn body_ids(bodies: &BTreeMap<hir::BodyId, hir::Body<'_>>) -> Vec<hir::BodyId> {
Expand Down
1 change: 1 addition & 0 deletions compiler/rustc_ast_passes/Cargo.toml
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Original file line number Diff line number Diff line change
Expand Up @@ -14,4 +14,5 @@ rustc_feature = { path = "../rustc_feature" }
rustc_parse = { path = "../rustc_parse" }
rustc_session = { path = "../rustc_session" }
rustc_span = { path = "../rustc_span" }
rustc_target = { path = "../rustc_target" }
rustc_ast = { path = "../rustc_ast" }
43 changes: 41 additions & 2 deletions compiler/rustc_ast_passes/src/ast_validation.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -15,12 +15,13 @@ use rustc_ast_pretty::pprust;
use rustc_data_structures::fx::FxHashMap;
use rustc_errors::{error_code, pluralize, struct_span_err, Applicability};
use rustc_parse::validate_attr;
use rustc_session::lint::builtin::PATTERNS_IN_FNS_WITHOUT_BODY;
use rustc_session::lint::builtin::{MISSING_ABI, PATTERNS_IN_FNS_WITHOUT_BODY};
use rustc_session::lint::{BuiltinLintDiagnostics, LintBuffer};
use rustc_session::Session;
use rustc_span::source_map::Spanned;
use rustc_span::symbol::{kw, sym, Ident};
use rustc_span::Span;
use rustc_target::spec::abi;
use std::mem;
use std::ops::DerefMut;

Expand Down Expand Up @@ -844,6 +845,10 @@ impl<'a> AstValidator<'a> {
.emit();
});
self.check_late_bound_lifetime_defs(&bfty.generic_params);
if let Extern::Implicit = bfty.ext {
let sig_span = self.session.source_map().next_point(ty.span.shrink_to_lo());
self.maybe_lint_missing_abi(sig_span, ty.id);
}
}
TyKind::TraitObject(ref bounds, ..) => {
let mut any_lifetime_bounds = false;
Expand Down Expand Up @@ -894,6 +899,26 @@ impl<'a> AstValidator<'a> {
_ => {}
}
}

fn maybe_lint_missing_abi(&mut self, span: Span, id: NodeId) {
// FIXME(davidtwco): This is a hack to detect macros which produce spans of the
// call site which do not have a macro backtrace. See #61963.
Comment on lines +904 to +905
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Should we have some way to enable this to push the proc-macro ecosystem in the right direction?

let is_macro_callsite = self
.session
.source_map()
.span_to_snippet(span)
.map(|snippet| snippet.starts_with("#["))
.unwrap_or(true);
if !is_macro_callsite {
self.lint_buffer.buffer_lint_with_diagnostic(
MISSING_ABI,
id,
span,
"extern declarations without an explicit ABI are deprecated",
BuiltinLintDiagnostics::MissingAbi(span, abi::Abi::FALLBACK),
)
}
}
}

/// Checks that generic parameters are in the correct order,
Expand Down Expand Up @@ -1178,7 +1203,7 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
walk_list!(self, visit_attribute, &item.attrs);
return; // Avoid visiting again.
}
ItemKind::ForeignMod(ForeignMod { unsafety, .. }) => {
ItemKind::ForeignMod(ForeignMod { abi, unsafety, .. }) => {
let old_item = mem::replace(&mut self.extern_mod, Some(item));
self.invalid_visibility(
&item.vis,
Expand All @@ -1187,6 +1212,9 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
if let Unsafe::Yes(span) = unsafety {
self.err_handler().span_err(span, "extern block cannot be declared unsafe");
}
if abi.is_none() {
self.maybe_lint_missing_abi(item.span, item.id);
}
visit::walk_item(self, item);
self.extern_mod = old_item;
return; // Avoid visiting again.
Expand Down Expand Up @@ -1526,6 +1554,17 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
.emit();
}

if let FnKind::Fn(
_,
_,
FnSig { span: sig_span, header: FnHeader { ext: Extern::Implicit, .. }, .. },
_,
_,
) = fk
{
self.maybe_lint_missing_abi(*sig_span, id);
}

// Functions without bodies cannot have patterns.
if let FnKind::Fn(ctxt, _, sig, _, None) = fk {
Self::check_decl_no_pat(&sig.decl, |span, ident, mut_ident| {
Expand Down
3 changes: 3 additions & 0 deletions compiler/rustc_target/src/spec/abi.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -87,6 +87,9 @@ pub fn all_names() -> Vec<&'static str> {
}

impl Abi {
/// Default ABI chosen for `extern fn` declarations without an explicit ABI.
pub const FALLBACK: Abi = Abi::C { unwind: false };

#[inline]
pub fn index(self) -> usize {
// N.B., this ordering MUST match the AbiDatas array above.
Expand Down