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Auto merge of #87146 - Aaron1011:better-macro-lint, r=petrochenkov

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Compute a better `lint_node_id` during expansion

When we need to emit a lint at a macro invocation, we currently use the
`NodeId` of its parent definition (e.g. the enclosing function). This
means that any `#[allow]` / `#[deny]` attributes placed 'closer' to the
macro (e.g. on an enclosing block or statement) will have no effect.

This commit computes a better `lint_node_id` in `InvocationCollector`.
When we visit/flat_map an AST node, we assign it a `NodeId` (earlier
than we normally would), and store than `NodeId` in current
`ExpansionData`. When we collect a macro invocation, the current
`lint_node_id` gets cloned along with our `ExpansionData`, allowing it
to be used if we need to emit a lint later on.

This improves the handling of `#[allow]` / `#[deny]` for
`SEMICOLON_IN_EXPRESSIONS_FROM_MACROS` and some `asm!`-related lints.
The 'legacy derive helpers' lint retains its current behavior
(I've inlined the now-removed `lint_node_id` function), since
there isn't an `ExpansionData` readily available.
This commit is contained in:
bors 2021-07-19 04:22:51 +00:00
commit 0ecff8c623
13 changed files with 226 additions and 59 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
compiler/rustc_builtin_macros/src/asm.rs
View File

@ -455,7 +455,7 @@ fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, args: AsmArgs) -> Option<ast::Inl
ecx.parse_sess().buffer_lint(
lint::builtin::BAD_ASM_STYLE,
find_span(".intel_syntax"),
ecx.resolver.lint_node_id(ecx.current_expansion.id),
ecx.current_expansion.lint_node_id,
"avoid using `.intel_syntax`, Intel syntax is the default",
);
}
@ -463,7 +463,7 @@ fn expand_preparsed_asm(ecx: &mut ExtCtxt<'_>, args: AsmArgs) -> Option<ast::Inl
ecx.parse_sess().buffer_lint(
lint::builtin::BAD_ASM_STYLE,
find_span(".att_syntax"),
ecx.resolver.lint_node_id(ecx.current_expansion.id),
ecx.current_expansion.lint_node_id,
"avoid using `.att_syntax`, prefer using `options(att_syntax)` instead",
);
}

2
compiler/rustc_builtin_macros/src/source_util.rs
View File

@ -159,7 +159,7 @@ fn make_expr(mut self: Box<ExpandResult<'a>>) -> Option<P<ast::Expr>> {
}
}
Box::new(ExpandResult { p, node_id: cx.resolver.lint_node_id(cx.current_expansion.id) })
Box::new(ExpandResult { p, node_id: cx.current_expansion.lint_node_id })
}
// include_str! : read the given file, insert it as a literal string expr

9
compiler/rustc_expand/src/base.rs
View File

@ -29,6 +29,9 @@
crate use rustc_span::hygiene::MacroKind;
// When adding new variants, make sure to
// adjust the `visit_*` / `flat_map_*` calls in `InvocationCollector`
// to use `assign_id!`
#[derive(Debug, Clone)]
pub enum Annotatable {
Item(P<ast::Item>),
@ -869,9 +872,6 @@ fn resolve_macro_invocation(
fn check_unused_macros(&mut self);
/// Some parent node that is close enough to the given macro call.
fn lint_node_id(&self, expn_id: LocalExpnId) -> NodeId;
// Resolver interfaces for specific built-in macros.
/// Does `#[derive(...)]` attribute with the given `ExpnId` have built-in `Copy` inside it?
fn has_derive_copy(&self, expn_id: LocalExpnId) -> bool;
@ -926,6 +926,8 @@ pub struct ExpansionData {
pub module: Rc<ModuleData>,
pub dir_ownership: DirOwnership,
pub prior_type_ascription: Option<(Span, bool)>,
/// Some parent node that is close to this macro call
pub lint_node_id: NodeId,
}
type OnExternModLoaded<'a> =
@ -971,6 +973,7 @@ pub fn new(
module: Default::default(),
dir_ownership: DirOwnership::Owned { relative: None },
prior_type_ascription: None,
lint_node_id: ast::CRATE_NODE_ID,
},
force_mode: false,
expansions: FxHashMap::default(),

103
compiler/rustc_expand/src/expand.rs
View File

@ -12,7 +12,7 @@
use rustc_ast::token;
use rustc_ast::tokenstream::TokenStream;
use rustc_ast::visit::{self, AssocCtxt, Visitor};
use rustc_ast::{AstLike, Block, Inline, ItemKind, MacArgs};
use rustc_ast::{AstLike, Block, Inline, ItemKind, Local, MacArgs};
use rustc_ast::{MacCallStmt, MacStmtStyle, MetaItemKind, ModKind, NestedMetaItem};
use rustc_ast::{NodeId, PatKind, Path, StmtKind, Unsafe};
use rustc_ast_pretty::pprust;
@ -1098,6 +1098,43 @@ fn check_attributes(&mut self, attrs: &[ast::Attribute]) {
}
}
/// Wraps a call to `noop_visit_*` / `noop_flat_map_*`
/// for an AST node that supports attributes
/// (see the `Annotatable` enum)
/// This method assigns a `NodeId`, and sets that `NodeId`
/// as our current 'lint node id'. If a macro call is found
/// inside this AST node, we will use this AST node's `NodeId`
/// to emit lints associated with that macro (allowing
/// `#[allow]` / `#[deny]` to be applied close to
/// the macro invocation).
///
/// Do *not* call this for a macro AST node
/// (e.g. `ExprKind::MacCall`) - we cannot emit lints
/// at these AST nodes, since they are removed and
/// replaced with the result of macro expansion.
///
/// All other `NodeId`s are assigned by `visit_id`.
/// * `self` is the 'self' parameter for the current method,
/// * `id` is a mutable reference to the `NodeId` field
/// of the current AST node.
/// * `closure` is a closure that executes the
/// `noop_visit_*` / `noop_flat_map_*` method
/// for the current AST node.
macro_rules! assign_id {
($self:ident, $id:expr, $closure:expr) => {{
let old_id = $self.cx.current_expansion.lint_node_id;
if $self.monotonic {
debug_assert_eq!(*$id, ast::DUMMY_NODE_ID);
let new_id = $self.cx.resolver.next_node_id();
*$id = new_id;
$self.cx.current_expansion.lint_node_id = new_id;
}
let ret = ($closure)();
$self.cx.current_expansion.lint_node_id = old_id;
ret
}};
}
impl<'a, 'b> MutVisitor for InvocationCollector<'a, 'b> {
fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
self.cfg.configure_expr(expr);
@ -1118,12 +1155,19 @@ fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
self.check_attributes(&expr.attrs);
self.collect_bang(mac, expr.span, AstFragmentKind::Expr).make_expr().into_inner()
} else {
ensure_sufficient_stack(|| noop_visit_expr(&mut expr, self));
assign_id!(self, &mut expr.id, || {
ensure_sufficient_stack(|| noop_visit_expr(&mut expr, self));
});
expr
}
});
}
// This is needed in order to set `lint_node_id` for `let` statements
fn visit_local(&mut self, local: &mut P<Local>) {
assign_id!(self, &mut local.id, || noop_visit_local(local, self));
}
fn flat_map_arm(&mut self, arm: ast::Arm) -> SmallVec<[ast::Arm; 1]> {
let mut arm = configure!(self, arm);
@ -1133,7 +1177,7 @@ fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
.make_arms();
}
noop_flat_map_arm(arm, self)
assign_id!(self, &mut arm.id, || noop_flat_map_arm(arm, self))
}
fn flat_map_expr_field(&mut self, field: ast::ExprField) -> SmallVec<[ast::ExprField; 1]> {
@ -1145,7 +1189,7 @@ fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
.make_expr_fields();
}
noop_flat_map_expr_field(field, self)
assign_id!(self, &mut field.id, || noop_flat_map_expr_field(field, self))
}
fn flat_map_pat_field(&mut self, fp: ast::PatField) -> SmallVec<[ast::PatField; 1]> {
@ -1157,7 +1201,7 @@ fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
.make_pat_fields();
}
noop_flat_map_pat_field(fp, self)
assign_id!(self, &mut fp.id, || noop_flat_map_pat_field(fp, self))
}
fn flat_map_param(&mut self, p: ast::Param) -> SmallVec<[ast::Param; 1]> {
@ -1169,7 +1213,7 @@ fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
.make_params();
}
noop_flat_map_param(p, self)
assign_id!(self, &mut p.id, || noop_flat_map_param(p, self))
}
fn flat_map_field_def(&mut self, sf: ast::FieldDef) -> SmallVec<[ast::FieldDef; 1]> {
@ -1181,7 +1225,7 @@ fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
.make_field_defs();
}
noop_flat_map_field_def(sf, self)
assign_id!(self, &mut sf.id, || noop_flat_map_field_def(sf, self))
}
fn flat_map_variant(&mut self, variant: ast::Variant) -> SmallVec<[ast::Variant; 1]> {
@ -1193,7 +1237,7 @@ fn visit_expr(&mut self, expr: &mut P<ast::Expr>) {
.make_variants();
}
noop_flat_map_variant(variant, self)
assign_id!(self, &mut variant.id, || noop_flat_map_variant(variant, self))
}
fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
@ -1214,9 +1258,11 @@ fn filter_map_expr(&mut self, expr: P<ast::Expr>) -> Option<P<ast::Expr>> {
.make_opt_expr()
.map(|expr| expr.into_inner())
} else {
Some({
noop_visit_expr(&mut expr, self);
expr
assign_id!(self, &mut expr.id, || {
Some({
noop_visit_expr(&mut expr, self);
expr
})
})
}
})
@ -1266,6 +1312,8 @@ fn visit_pat(&mut self, pat: &mut P<ast::Pat>) {
}
// The placeholder expander gives ids to statements, so we avoid folding the id here.
// We don't use `assign_id!` - it will be called when we visit statement's contents
// (e.g. an expression, item, or local)
let ast::Stmt { id, kind, span } = stmt;
noop_flat_map_stmt_kind(kind, self)
.into_iter()
@ -1377,7 +1425,7 @@ fn visit_block(&mut self, block: &mut P<Block>) {
let orig_dir_ownership =
mem::replace(&mut self.cx.current_expansion.dir_ownership, dir_ownership);
let result = noop_flat_map_item(item, self);
let result = assign_id!(self, &mut item.id, || noop_flat_map_item(item, self));
// Restore the module info.
self.cx.current_expansion.dir_ownership = orig_dir_ownership;
@ -1387,7 +1435,12 @@ fn visit_block(&mut self, block: &mut P<Block>) {
}
_ => {
item.attrs = attrs;
noop_flat_map_item(item, self)
// The crate root is special - don't assign an ID to it.
if !(matches!(item.kind, ast::ItemKind::Mod(..)) && ident == Ident::invalid()) {
assign_id!(self, &mut item.id, || noop_flat_map_item(item, self))
} else {
noop_flat_map_item(item, self)
}
}
}
}
@ -1411,7 +1464,9 @@ fn visit_block(&mut self, block: &mut P<Block>) {
_ => unreachable!(),
})
}
_ => noop_flat_map_assoc_item(item, self),
_ => {
assign_id!(self, &mut item.id, || noop_flat_map_assoc_item(item, self))
}
}
}
@ -1434,7 +1489,9 @@ fn visit_block(&mut self, block: &mut P<Block>) {
_ => unreachable!(),
})
}
_ => noop_flat_map_assoc_item(item, self),
_ => {
assign_id!(self, &mut item.id, || noop_flat_map_assoc_item(item, self))
}
}
}
@ -1478,7 +1535,12 @@ fn flat_map_foreign_item(
_ => unreachable!(),
})
}
_ => noop_flat_map_foreign_item(foreign_item, self),
_ => {
assign_id!(self, &mut foreign_item.id, || noop_flat_map_foreign_item(
foreign_item,
self
))
}
}
}
@ -1498,13 +1560,14 @@ fn flat_map_generic_param(
.make_generic_params();
}
noop_flat_map_generic_param(param, self)
assign_id!(self, &mut param.id, || noop_flat_map_generic_param(param, self))
}
fn visit_id(&mut self, id: &mut ast::NodeId) {
if self.monotonic {
debug_assert_eq!(*id, ast::DUMMY_NODE_ID);
*id = self.cx.resolver.next_node_id()
// We may have already assigned a `NodeId`
// by calling `assign_id`
if self.monotonic && *id == ast::DUMMY_NODE_ID {
*id = self.cx.resolver.next_node_id();
}
}
}

3
compiler/rustc_expand/src/mbe/macro_rules.rs
View File

@ -289,7 +289,6 @@ fn generic_extension<'cx>(
let mut p = Parser::new(sess, tts, false, None);
p.last_type_ascription = cx.current_expansion.prior_type_ascription;
let lint_node_id = cx.resolver.lint_node_id(cx.current_expansion.id);
// Let the context choose how to interpret the result.
// Weird, but useful for X-macros.
@ -301,7 +300,7 @@ fn generic_extension<'cx>(
// macro leaves unparsed tokens.
site_span: sp,
macro_ident: name,
lint_node_id,
lint_node_id: cx.current_expansion.lint_node_id,
arm_span,
});
}

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

@ -120,6 +120,12 @@ fn visit_expr(&mut self, e: &'a ast::Expr) {
})
}
fn visit_expr_field(&mut self, f: &'a ast::ExprField) {
self.with_lint_attrs(f.id, &f.attrs, |cx| {
ast_visit::walk_expr_field(cx, f);
})
}
fn visit_stmt(&mut self, s: &'a ast::Stmt) {
// Add the statement's lint attributes to our
// current state when checking the statement itself.
@ -204,8 +210,10 @@ fn visit_block(&mut self, b: &'a ast::Block) {
}
fn visit_arm(&mut self, a: &'a ast::Arm) {
run_early_pass!(self, check_arm, a);
ast_visit::walk_arm(self, a);
self.with_lint_attrs(a.id, &a.attrs, |cx| {
run_early_pass!(cx, check_arm, a);
ast_visit::walk_arm(cx, a);
})
}
fn visit_expr_post(&mut self, e: &'a ast::Expr) {
@ -389,9 +397,15 @@ pub fn check_ast_crate<T: EarlyLintPass>(
// All of the buffered lints should have been emitted at this point.
// If not, that means that we somehow buffered a lint for a node id
// that was not lint-checked (perhaps it doesn't exist?). This is a bug.
for (_id, lints) in buffered.map {
for (id, lints) in buffered.map {
for early_lint in lints {
sess.delay_span_bug(early_lint.span, "failed to process buffered lint here");
sess.delay_span_bug(
early_lint.span,
&format!(
"failed to process buffered lint here (dummy = {})",
id == ast::DUMMY_NODE_ID
),
);
}
}
}

4
compiler/rustc_lint_defs/src/lib.rs
View File

@ -274,7 +274,7 @@ fn to_stable_hash_key(&self, _: &HCX) -> &'static str {
}
// Duplicated from rustc_session::config::ExternDepSpec to avoid cyclic dependency
#[derive(PartialEq)]
#[derive(PartialEq, Debug)]
pub enum ExternDepSpec {
Json(Json),
Raw(String),
@ -282,7 +282,7 @@ pub enum ExternDepSpec {
// This could be a closure, but then implementing derive trait
// becomes hacky (and it gets allocated).
#[derive(PartialEq)]
#[derive(PartialEq, Debug)]
pub enum BuiltinLintDiagnostics {
Normal,
BareTraitObject(Span, /* is_global */ bool),

16
compiler/rustc_resolve/src/macros.rs
View File

@ -281,7 +281,7 @@ fn resolve_macro_invocation(
// Derives are not included when `invocations` are collected, so we have to add them here.
let parent_scope = &ParentScope { derives, ..parent_scope };
let supports_macro_expansion = invoc.fragment_kind.supports_macro_expansion();
let node_id = self.lint_node_id(eager_expansion_root);
let node_id = invoc.expansion_data.lint_node_id;
let (ext, res) = self.smart_resolve_macro_path(
path,
kind,
@ -348,14 +348,6 @@ fn check_unused_macros(&mut self) {
}
}
fn lint_node_id(&self, expn_id: LocalExpnId) -> NodeId {
// FIXME - make this more precise. This currently returns the NodeId of the
// nearest closing item - we should try to return the closest parent of the ExpnId
self.invocation_parents
.get(&expn_id)
.map_or(ast::CRATE_NODE_ID, |id| self.def_id_to_node_id[id.0])
}
fn has_derive_copy(&self, expn_id: LocalExpnId) -> bool {
self.containers_deriving_copy.contains(&expn_id)
}
@ -1105,9 +1097,13 @@ struct Flags: u8 {
let seg = Segment::from_ident(ident);
check_consistency(self, &[seg], ident.span, kind, initial_res, res);
if res == Res::NonMacroAttr(NonMacroAttrKind::DeriveHelperCompat) {
let node_id = self
.invocation_parents
.get(&parent_scope.expansion)
.map_or(ast::CRATE_NODE_ID, |id| self.def_id_to_node_id[id.0]);
self.lint_buffer.buffer_lint_with_diagnostic(
LEGACY_DERIVE_HELPERS,
self.lint_node_id(parent_scope.expansion),
node_id,
ident.span,
"derive helper attribute is used before it is introduced",
BuiltinLintDiagnostics::LegacyDeriveHelpers(binding.span),

24
src/test/ui/lint/semicolon-in-expressions-from-macros/semicolon-in-expressions-from-macros.rs
View File

@ -1,14 +1,17 @@
// check-pass
// edition:2018
#![feature(stmt_expr_attributes)]
#![warn(semicolon_in_expressions_from_macros)]
#[allow(dead_code)]
macro_rules! foo {
($val:ident) => {
true; //~ WARN trailing
//~| WARN this was previously
//~| WARN trailing
//~| WARN this was previously
true; //~ WARN trailing semicolon in macro
//~| WARN this was previously accepted
//~| WARN trailing semicolon in macro
//~| WARN this was previously accepted
//~| WARN trailing semicolon in macro
//~| WARN this was previously accepted
}
}
@ -18,17 +21,14 @@ async fn bar() {
}
fn main() {
// This `allow` doesn't work
#[allow(semicolon_in_expressions_from_macros)]
let _ = {
foo!(first)
};
// This 'allow' doesn't work either
#[allow(semicolon_in_expressions_from_macros)]
let _ = foo!(second);
// But this 'allow' does
#[allow(semicolon_in_expressions_from_macros)]
fn inner() {
let _ = foo!(third);
@ -38,4 +38,14 @@ fn inner() {
async {
let _ = foo!(fourth);
};
let _ = {
foo!(warn_in_block)
};
let _ = foo!(warn_in_expr);
// This `#[allow]` does not work, since the attribute gets dropped
// when we expand the macro
let _ = #[allow(semicolon_in_expressions_from_macros)] foo!(allow_does_not_work);
}

29
src/test/ui/lint/semicolon-in-expressions-from-macros/semicolon-in-expressions-from-macros.stderr
View File

@ -1,14 +1,14 @@
warning: trailing semicolon in macro used in expression position
--> $DIR/semicolon-in-expressions-from-macros.rs:8:13
--> $DIR/semicolon-in-expressions-from-macros.rs:9:13
|
LL | true;
| ^
...
LL | foo!(first)
| ----------- in this macro invocation
LL | foo!(warn_in_block)
| ------------------- in this macro invocation
|
note: the lint level is defined here
--> $DIR/semicolon-in-expressions-from-macros.rs:3:9
--> $DIR/semicolon-in-expressions-from-macros.rs:4:9
|
LL | #![warn(semicolon_in_expressions_from_macros)]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@ -17,17 +17,30 @@ LL | #![warn(semicolon_in_expressions_from_macros)]
= note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
warning: trailing semicolon in macro used in expression position
--> $DIR/semicolon-in-expressions-from-macros.rs:8:13
--> $DIR/semicolon-in-expressions-from-macros.rs:9:13
|
LL | true;
| ^
...
LL | let _ = foo!(second);
| ------------ in this macro invocation
LL | let _ = foo!(warn_in_expr);
| ------------------ in this macro invocation
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
= note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
warning: 2 warnings emitted
warning: trailing semicolon in macro used in expression position
--> $DIR/semicolon-in-expressions-from-macros.rs:9:13
|
LL | true;
| ^
...
LL | let _ = #[allow(semicolon_in_expressions_from_macros)] foo!(allow_does_not_work);
| ------------------------- in this macro invocation
|
= warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
= note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
= note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
warning: 3 warnings emitted

19
src/test/ui/proc-macro/auxiliary/call-deprecated.rs Normal file
View File

@ -0,0 +1,19 @@
// force-host
// no-prefer-dynamic
#![crate_type = "proc-macro"]
extern crate proc_macro;
use proc_macro::*;
#[proc_macro_attribute]
#[deprecated(since = "1.0.0", note = "test")]
pub fn attr(_: TokenStream, input: TokenStream) -> TokenStream {
input
}
#[proc_macro_attribute]
#[deprecated(since = "1.0.0", note = "test")]
pub fn attr_remove(_: TokenStream, _: TokenStream) -> TokenStream {
TokenStream::new()
}

34
src/test/ui/proc-macro/call-deprecated.rs Normal file
View File

@ -0,0 +1,34 @@
// check-pass
// aux-build:call-deprecated.rs
extern crate call_deprecated;
// These first two `#[allow(deprecated)]` attributes
// do nothing, since the AST nodes for `First` and `Second`
// haven't been been assigned a `NodeId`.
// See #63221 for a discussion about how we should
// handle the interaction of 'inert' attributes and
// proc-macro attributes.
#[allow(deprecated)]
#[call_deprecated::attr] //~ WARN use of deprecated macro
struct First;
#[allow(deprecated)]
#[call_deprecated::attr_remove] //~ WARN use of deprecated macro
struct Second;
#[allow(deprecated)]
mod bar {
#[allow(deprecated)]
#[call_deprecated::attr]
struct Third;
#[allow(deprecated)]
#[call_deprecated::attr_remove]
struct Fourth;
}
fn main() {
}

16
src/test/ui/proc-macro/call-deprecated.stderr Normal file
View File

@ -0,0 +1,16 @@
warning: use of deprecated macro `call_deprecated::attr`: test
--> $DIR/call-deprecated.rs:14:3
|
LL | #[call_deprecated::attr]
| ^^^^^^^^^^^^^^^^^^^^^
|
= note: `#[warn(deprecated)]` on by default
warning: use of deprecated macro `call_deprecated::attr_remove`: test
--> $DIR/call-deprecated.rs:18:3
|
LL | #[call_deprecated::attr_remove]
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
warning: 2 warnings emitted