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Add framework for the extern keyword. (#3755)

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This doesn't add full support. I'm separating it out to make the effects
of the modifier changes clearer for review. I'm restructuring a little
with the expectation that we'll have some more categories of modifier
keywords in the future (similar to `extern`, these may not be in a "set"
such as access), and thus easily scaling up to a few more would be
useful.
This commit is contained in:
Jon Ross-Perkins
2024-03-08 16:01:12 +00:00
committed by GitHub
parent 56d70dc3a2
commit 096daecc57
21 changed files with 241 additions and 102 deletions
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toolchain/check/handle_modifier.cpp
+36 -10
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@@ -37,26 +37,52 @@ static auto EmitNotAllowedWithDiagnostic(Context& context,
static auto HandleModifier(Context& context, Parse::NodeId parse_node,
KeywordModifierSet keyword) -> bool {
auto& s = context.decl_state_stack().innermost();
bool is_access = !!(keyword & KeywordModifierSet::Access);
auto& saw_modifier = is_access ? s.saw_access_modifier : s.saw_decl_modifier;
ModifierOrder order;
KeywordModifierSet later_modifiers;
if (!!(keyword & KeywordModifierSet::Access)) {
order = ModifierOrder::Access;
later_modifiers = KeywordModifierSet::Extern | KeywordModifierSet::Decl;
} else if (keyword == KeywordModifierSet::Extern) {
order = ModifierOrder::Extern;
later_modifiers = KeywordModifierSet::Decl;
} else {
order = ModifierOrder::Decl;
later_modifiers = KeywordModifierSet::None;
}
auto current_modifier_node_id = s.modifier_node_id(order);
if (!!(s.modifier_set & keyword)) {
EmitRepeatedDiagnostic(context, saw_modifier, parse_node);
} else if (saw_modifier.is_valid()) {
EmitNotAllowedWithDiagnostic(context, saw_modifier, parse_node);
} else if (is_access && s.saw_decl_modifier.is_valid()) {
EmitRepeatedDiagnostic(context, current_modifier_node_id, parse_node);
} else if (current_modifier_node_id.is_valid()) {
EmitNotAllowedWithDiagnostic(context, current_modifier_node_id, parse_node);
} else if (auto later_modifier_set = s.modifier_set & later_modifiers;
!!later_modifier_set) {
// At least one later modifier is present. Diagnose using the closest.
Parse::NodeId closest_later_modifier = Parse::NodeId::Invalid;
for (auto later_order = static_cast<int8_t>(order) + 1;
later_order <= static_cast<int8_t>(ModifierOrder::Last);
++later_order) {
if (s.ordered_modifier_node_ids[later_order] != Parse::NodeId::Invalid) {
closest_later_modifier = s.ordered_modifier_node_ids[later_order];
break;
}
}
CARBON_CHECK(closest_later_modifier.is_valid());
CARBON_DIAGNOSTIC(ModifierMustAppearBefore, Error,
"`{0}` must appear before `{1}`.", Lex::TokenKind,
Lex::TokenKind);
context.emitter()
.Build(parse_node, ModifierMustAppearBefore,
context.token_kind(parse_node),
context.token_kind(s.saw_decl_modifier))
.Note(s.saw_decl_modifier, ModifierPrevious,
context.token_kind(s.saw_decl_modifier))
context.token_kind(closest_later_modifier))
.Note(closest_later_modifier, ModifierPrevious,
context.token_kind(closest_later_modifier))
.Emit();
} else {
s.modifier_set |= keyword;
saw_modifier = parse_node;
s.set_modifier_node_id(order, parse_node);
}
return true;
}