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Use adt_def during type collection. #103759

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merged 3 commits into from
Nov 1, 2022
Merged

Use adt_def during type collection. #103759

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6802e1d
Use AdtDef in wfcheck.
cjgillot Oct 30, 2022
65f77b7
Use adt_def for ADT collection.
cjgillot Oct 30, 2022
abc1ad7
Use AdtDef to check enum.
cjgillot Oct 30, 2022
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121 changes: 62 additions & 59 deletions compiler/rustc_hir_analysis/src/check/check.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ use super::*;
use rustc_attr as attr;
use rustc_errors::{Applicability, ErrorGuaranteed, MultiSpan};
use rustc_hir as hir;
use rustc_hir::def::{DefKind, Res};
use rustc_hir::def::{CtorKind, DefKind, Res};
use rustc_hir::def_id::{DefId, LocalDefId};
use rustc_hir::intravisit::Visitor;
use rustc_hir::{ItemKind, Node, PathSegment};
Expand Down Expand Up @@ -75,15 +75,15 @@ fn check_struct(tcx: TyCtxt<'_>, def_id: LocalDefId) {
check_simd(tcx, span, def_id);
}

check_transparent(tcx, span, def);
check_transparent(tcx, def);
check_packed(tcx, span, def);
}

fn check_union(tcx: TyCtxt<'_>, def_id: LocalDefId) {
let def = tcx.adt_def(def_id);
let span = tcx.def_span(def_id);
def.destructor(tcx); // force the destructor to be evaluated
check_transparent(tcx, span, def);
check_transparent(tcx, def);
check_union_fields(tcx, span, def_id);
check_packed(tcx, span, def);
}
Expand Down Expand Up @@ -506,11 +506,7 @@ fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
tcx.ensure().typeck(id.owner_id.def_id);
}
DefKind::Enum => {
let item = tcx.hir().item(id);
let hir::ItemKind::Enum(ref enum_definition, _) = item.kind else {
return;
};
check_enum(tcx, &enum_definition.variants, item.owner_id.def_id);
check_enum(tcx, id.owner_id.def_id);
}
DefKind::Fn => {} // entirely within check_item_body
DefKind::Impl => {
Expand Down Expand Up @@ -1026,7 +1022,7 @@ pub(super) fn check_packed_inner(
None
}

pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: ty::AdtDef<'tcx>) {
pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>) {
if !adt.repr().transparent() {
return;
}
Expand All @@ -1035,14 +1031,14 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: ty::AdtD
feature_err(
&tcx.sess.parse_sess,
sym::transparent_unions,
sp,
tcx.def_span(adt.did()),
"transparent unions are unstable",
)
.emit();
}

if adt.variants().len() != 1 {
bad_variant_count(tcx, adt, sp, adt.did());
bad_variant_count(tcx, adt, tcx.def_span(adt.did()), adt.did());
if adt.variants().is_empty() {
// Don't bother checking the fields. No variants (and thus no fields) exist.
return;
Expand Down Expand Up @@ -1103,7 +1099,7 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: ty::AdtD
.filter_map(|(span, zst, _align1, _non_exhaustive)| if !zst { Some(span) } else { None });
let non_zst_count = non_zst_fields.clone().count();
if non_zst_count >= 2 {
bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, sp);
bad_non_zero_sized_fields(tcx, adt, non_zst_count, non_zst_fields, tcx.def_span(adt.did()));
}
let incompatible_zst_fields =
field_infos.clone().filter(|(_, _, _, opt)| opt.is_some()).count();
Expand Down Expand Up @@ -1143,20 +1139,19 @@ pub(super) fn check_transparent<'tcx>(tcx: TyCtxt<'tcx>, sp: Span, adt: ty::AdtD
}

#[allow(trivial_numeric_casts)]
fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, vs: &'tcx [hir::Variant<'tcx>], def_id: LocalDefId) {
fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, def_id: LocalDefId) {
let def = tcx.adt_def(def_id);
let sp = tcx.def_span(def_id);
def.destructor(tcx); // force the destructor to be evaluated

if vs.is_empty() {
if def.variants().is_empty() {
if let Some(attr) = tcx.get_attrs(def_id.to_def_id(), sym::repr).next() {
struct_span_err!(
tcx.sess,
attr.span,
E0084,
"unsupported representation for zero-variant enum"
)
.span_label(sp, "zero-variant enum")
.span_label(tcx.def_span(def_id), "zero-variant enum")
.emit();
}
}
Expand All @@ -1167,88 +1162,96 @@ fn check_enum<'tcx>(tcx: TyCtxt<'tcx>, vs: &'tcx [hir::Variant<'tcx>], def_id: L
feature_err(
&tcx.sess.parse_sess,
sym::repr128,
sp,
tcx.def_span(def_id),
"repr with 128-bit type is unstable",
)
.emit();
}
}

for v in vs {
if let Some(ref e) = v.disr_expr {
tcx.ensure().typeck(tcx.hir().local_def_id(e.hir_id));
for v in def.variants() {
if let ty::VariantDiscr::Explicit(discr_def_id) = v.discr {
tcx.ensure().typeck(discr_def_id.expect_local());
}
}

if tcx.adt_def(def_id).repr().int.is_none() {
let is_unit = |var: &hir::Variant<'_>| matches!(var.data, hir::VariantData::Unit(..));
if def.repr().int.is_none() {
let is_unit = |var: &ty::VariantDef| matches!(var.ctor_kind, CtorKind::Const);
let has_disr = |var: &ty::VariantDef| matches!(var.discr, ty::VariantDiscr::Explicit(_));

let has_disr = |var: &hir::Variant<'_>| var.disr_expr.is_some();
let has_non_units = vs.iter().any(|var| !is_unit(var));
let disr_units = vs.iter().any(|var| is_unit(&var) && has_disr(&var));
let disr_non_unit = vs.iter().any(|var| !is_unit(&var) && has_disr(&var));
let has_non_units = def.variants().iter().any(|var| !is_unit(var));
let disr_units = def.variants().iter().any(|var| is_unit(&var) && has_disr(&var));
let disr_non_unit = def.variants().iter().any(|var| !is_unit(&var) && has_disr(&var));

if disr_non_unit || (disr_units && has_non_units) {
let mut err =
struct_span_err!(tcx.sess, sp, E0732, "`#[repr(inttype)]` must be specified");
let mut err = struct_span_err!(
tcx.sess,
tcx.def_span(def_id),
E0732,
"`#[repr(inttype)]` must be specified"
);
err.emit();
}
}

detect_discriminant_duplicate(tcx, def.discriminants(tcx).collect(), vs, sp);

check_transparent(tcx, sp, def);
detect_discriminant_duplicate(tcx, def);
check_transparent(tcx, def);
}

/// Part of enum check. Given the discriminants of an enum, errors if two or more discriminants are equal
fn detect_discriminant_duplicate<'tcx>(
tcx: TyCtxt<'tcx>,
mut discrs: Vec<(VariantIdx, Discr<'tcx>)>,
vs: &'tcx [hir::Variant<'tcx>],
self_span: Span,
) {
fn detect_discriminant_duplicate<'tcx>(tcx: TyCtxt<'tcx>, adt: ty::AdtDef<'tcx>) {
// Helper closure to reduce duplicate code. This gets called everytime we detect a duplicate.
// Here `idx` refers to the order of which the discriminant appears, and its index in `vs`
let report = |dis: Discr<'tcx>, idx: usize, err: &mut Diagnostic| {
let var = &vs[idx]; // HIR for the duplicate discriminant
let (span, display_discr) = match var.disr_expr {
Some(ref expr) => {
let report = |dis: Discr<'tcx>, idx, err: &mut Diagnostic| {
let var = adt.variant(idx); // HIR for the duplicate discriminant
let (span, display_discr) = match var.discr {
ty::VariantDiscr::Explicit(discr_def_id) => {
// In the case the discriminant is both a duplicate and overflowed, let the user know
if let hir::ExprKind::Lit(lit) = &tcx.hir().body(expr.body).value.kind
if let hir::Node::AnonConst(expr) = tcx.hir().get_by_def_id(discr_def_id.expect_local())
&& let hir::ExprKind::Lit(lit) = &tcx.hir().body(expr.body).value.kind
&& let rustc_ast::LitKind::Int(lit_value, _int_kind) = &lit.node
&& *lit_value != dis.val
{
(tcx.hir().span(expr.hir_id), format!("`{dis}` (overflowed from `{lit_value}`)"))
// Otherwise, format the value as-is
(tcx.def_span(discr_def_id), format!("`{dis}` (overflowed from `{lit_value}`)"))
} else {
(tcx.hir().span(expr.hir_id), format!("`{dis}`"))
// Otherwise, format the value as-is
(tcx.def_span(discr_def_id), format!("`{dis}`"))
}
}
None => {
// This should not happen.
ty::VariantDiscr::Relative(0) => (tcx.def_span(var.def_id), format!("`{dis}`")),
ty::VariantDiscr::Relative(distance_to_explicit) => {
// At this point we know this discriminant is a duplicate, and was not explicitly
// assigned by the user. Here we iterate backwards to fetch the HIR for the last
// explicitly assigned discriminant, and letting the user know that this was the
// increment startpoint, and how many steps from there leading to the duplicate
if let Some((n, hir::Variant { span, ident, .. })) =
vs[..idx].iter().rev().enumerate().find(|v| v.1.disr_expr.is_some())
if let Some(explicit_idx) =
idx.as_u32().checked_sub(distance_to_explicit).map(VariantIdx::from_u32)
{
let ve_ident = var.ident;
let n = n + 1;
let sp = if n > 1 { "variants" } else { "variant" };
let explicit_variant = adt.variant(explicit_idx);
let ve_ident = var.name;
let ex_ident = explicit_variant.name;
let sp = if distance_to_explicit > 1 { "variants" } else { "variant" };

err.span_label(
*span,
format!("discriminant for `{ve_ident}` incremented from this startpoint (`{ident}` + {n} {sp} later => `{ve_ident}` = {dis})"),
tcx.def_span(explicit_variant.def_id),
format!(
"discriminant for `{ve_ident}` incremented from this startpoint \
(`{ex_ident}` + {distance_to_explicit} {sp} later \
=> `{ve_ident}` = {dis})"
),
);
}

(vs[idx].span, format!("`{dis}`"))
(tcx.def_span(var.def_id), format!("`{dis}`"))
}
};

err.span_label(span, format!("{display_discr} assigned here"));
};

let mut discrs = adt.discriminants(tcx).collect::<Vec<_>>();

// Here we loop through the discriminants, comparing each discriminant to another.
// When a duplicate is detected, we instantiate an error and point to both
// initial and duplicate value. The duplicate discriminant is then discarded by swapping
Expand All @@ -1257,29 +1260,29 @@ fn detect_discriminant_duplicate<'tcx>(
// style as we are mutating `discrs` on the fly).
let mut i = 0;
while i < discrs.len() {
let hir_var_i_idx = discrs[i].0.index();
let var_i_idx = discrs[i].0;
let mut error: Option<DiagnosticBuilder<'_, _>> = None;

let mut o = i + 1;
while o < discrs.len() {
let hir_var_o_idx = discrs[o].0.index();
let var_o_idx = discrs[o].0;

if discrs[i].1.val == discrs[o].1.val {
let err = error.get_or_insert_with(|| {
let mut ret = struct_span_err!(
tcx.sess,
self_span,
tcx.def_span(adt.did()),
E0081,
"discriminant value `{}` assigned more than once",
discrs[i].1,
);

report(discrs[i].1, hir_var_i_idx, &mut ret);
report(discrs[i].1, var_i_idx, &mut ret);

ret
});

report(discrs[o].1, hir_var_o_idx, err);
report(discrs[o].1, var_o_idx, err);

// Safe to unwrap here, as we wouldn't reach this point if `discrs` was empty
discrs[o] = *discrs.last().unwrap();
Expand Down
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