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Superficial support for template modifier on symbolic bindings. (#4948)

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Change parse tree from `template (T:! type)` to `(template T):! type`,
so that we have information about whether a binding is a template
binding available when forming the representation of the binding
pattern. This incidentally fixes a bug that we would accept `template
addr A:! B` instead of the intended `addr template A:! B`.

Track whether a symbolic binding is a template binding on the
`EntityName` object. I'm borrowing a bit from the `CompileTimeBindIndex`
for this in order to avoid making `EntityName`s larger. Longer-term, we
should think about using a different representation for symbolic
bindings, to avoid including these fields in all `EntityName`s, but
that's out of scope for this change.

So far, template bindings are treated as having the same phase as
checked bindings, but that will change in a future PR.
This commit is contained in:
Richard Smith
2025-02-13 02:15:22 +00:00
committed by GitHub
parent f502e8d6ff
commit 6dda094928
32 changed files with 705 additions and 165 deletions
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toolchain/check/handle_binding_pattern.cpp
+29 -33
View File
@@ -28,23 +28,17 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
SemIR::ExprRegionId type_expr_region_id =
EndSubpatternAsExpr(context, cast_type_inst_id);
// The name in a template binding may be wrapped in `template`.
bool is_generic = node_kind == Parse::NodeKind::CompileTimeBindingPattern;
auto is_template =
context.node_stack()
.PopAndDiscardSoloNodeIdIf<Parse::NodeKind::TemplateBindingName>();
// A non-generic template binding is diagnosed by the parser.
is_template &= is_generic;
// Every other kind of pattern binding has a name.
auto [name_node, name_id] = context.node_stack().PopNameWithNodeId();
// Determine whether we're handling an associated constant. These share the
// syntax for a compile-time binding, but don't behave like other compile-time
// bindings.
// TODO: Consider using a different parse node kind to make this easier.
bool is_associated_constant = false;
bool is_generic = node_kind == Parse::NodeKind::CompileTimeBindingPattern;
if (is_generic) {
auto inst_id = context.scope_stack().PeekInstId();
is_associated_constant = inst_id.has_value() &&
context.insts().Is<SemIR::InterfaceDecl>(inst_id);
}
bool needs_compile_time_binding = is_generic && !is_associated_constant;
const DeclIntroducerState& introducer =
context.decl_introducer_state_stack().innermost();
@@ -53,16 +47,12 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
auto binding_pattern_id = SemIR::InstId::None;
// TODO: Eventually the name will need to support associations with other
// scopes, but right now we don't support qualified names here.
auto entity_name_id = context.entity_names().Add(
{.name_id = name_id,
.parent_scope_id = context.scope_stack().PeekNameScopeId(),
// TODO: Don't allocate a compile-time binding index for an associated
// constant declaration.
.bind_index = needs_compile_time_binding
? context.scope_stack().AddCompileTimeBinding()
: SemIR::CompileTimeBindIndex::None});
auto entity_name_id = context.entity_names().AddSymbolicBindingName(
name_id, context.scope_stack().PeekNameScopeId(),
is_generic ? context.scope_stack().AddCompileTimeBinding()
: SemIR::CompileTimeBindIndex::None,
is_template);
if (is_generic) {
// TODO: Create a `BindTemplateName` instead inside a `template` pattern.
bind_id = context.AddInstInNoBlock(SemIR::LocIdAndInst(
name_node, SemIR::BindSymbolicName{.type_id = cast_type_id,
.entity_name_id = entity_name_id,
@@ -83,7 +73,7 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
// Add name to lookup immediately, so it can be used in the rest of the
// enclosing pattern.
if (needs_compile_time_binding) {
if (is_generic) {
context.scope_stack().PushCompileTimeBinding(bind_id);
}
auto name_context =
@@ -114,7 +104,7 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
// so we handle it separately.
if (auto parent_class_decl =
context.scope_stack().GetCurrentScopeAs<SemIR::ClassDecl>();
parent_class_decl.has_value() &&
parent_class_decl.has_value() && !is_generic &&
node_kind == Parse::NodeKind::VarBindingPattern) {
cast_type_id = AsConcreteType(
context, cast_type_id, type_node,
@@ -131,9 +121,7 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
cast_type_id);
});
auto binding_id =
is_generic
? Parse::NodeId::None
: context.parse_tree().As<Parse::VarBindingPatternId>(node_id);
context.parse_tree().As<Parse::VarBindingPatternId>(node_id);
auto& class_info = context.classes().Get(parent_class_decl->class_id);
auto field_type_id =
context.GetUnboundElementType(class_info.self_type_id, cast_type_id);
@@ -157,12 +145,18 @@ static auto HandleAnyBindingPattern(Context& context, Parse::NodeId node_id,
context.scope_stack().GetCurrentScopeAs<SemIR::InterfaceDecl>();
parent_interface_decl.has_value() && is_generic) {
cast_type_id = AsCompleteType(context, cast_type_id, type_node, [&] {
CARBON_DIAGNOSTIC(IncompleteTypeInAssociatedDecl, Error,
CARBON_DIAGNOSTIC(IncompleteTypeInAssociatedConstantDecl, Error,
"associated constant has incomplete type {0}",
SemIR::TypeId);
return context.emitter().Build(type_node, IncompleteTypeInAssociatedDecl,
cast_type_id);
return context.emitter().Build(
type_node, IncompleteTypeInAssociatedConstantDecl, cast_type_id);
});
if (is_template) {
CARBON_DIAGNOSTIC(TemplateBindingInAssociatedConstantDecl, Error,
"associated constant has `template` binding");
context.emitter().Emit(type_node,
TemplateBindingInAssociatedConstantDecl);
}
SemIR::AssociatedConstantDecl assoc_const_decl = {
.type_id = cast_type_id,
@@ -357,8 +351,10 @@ auto HandleParseNode(Context& context, Parse::AddrId node_id) -> bool {
return true;
}
auto HandleParseNode(Context& context, Parse::TemplateId node_id) -> bool {
return context.TODO(node_id, "HandleTemplate");
auto HandleParseNode(Context& context, Parse::TemplateBindingNameId node_id)
-> bool {
context.node_stack().Push(node_id);
return true;
}
} // namespace Carbon::Check