carbon-lang/toolchain/check/import.h

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#ifndef CARBON_TOOLCHAIN_CHECK_IMPORT_H_
#define CARBON_TOOLCHAIN_CHECK_IMPORT_H_

#include "toolchain/check/context.h"
#include "toolchain/parse/node_ids.h"
#include "toolchain/sem_ir/file.h"

namespace Carbon::Check {

struct AddImportNamespaceResult {
  SemIR::NameScopeId name_scope_id;
  SemIR::InstId inst_id;
  bool is_duplicate_of_namespace_in_current_package;
};

// Adds a namespace to the IR. The bool on return is true if there was a name
// conflict. diagnose_duplicate_namespace is used when handling a cross-package
// import, where an existing namespace is in the current package and the new
// namespace is a different package.
auto AddImportNamespace(Context& context, SemIR::TypeId namespace_type_id,
                        SemIR::NameId name_id,
                        SemIR::NameScopeId parent_scope_id,
                        bool diagnose_duplicate_namespace,
                        llvm::function_ref<SemIR::InstId()> make_import_id)
    -> AddImportNamespaceResult;

// Imports the API file's name lookup information into a corresponding
// implementation file. Only information for the current package will be copied;
// information for other packages should be handled through
// ImportLibrariesFromOtherPackage.
auto ImportApiFile(Context& context, SemIR::TypeId namespace_type_id,
                   const SemIR::File& api_sem_ir) -> void;

// Add the current package's imports to name lookup. This pulls in all names;
// conflicts for things such as `package.a.b.c` will be flagged even though they
// are several layers deep.
auto ImportLibrariesFromCurrentPackage(
    Context& context, SemIR::TypeId namespace_type_id,
    llvm::ArrayRef<SemIR::ImportIR> import_irs) -> void;

// Adds another package's imports to name lookup. This only adds the package
// name to lookup, so that `package.ImportedPackage` will resolve, and will
// provide a name scope that can be used for further qualified name lookups.
//
// import_irs may be empty. has_load_error is used to indicate if any library in
// the package failed to import correctly.
auto ImportLibrariesFromOtherPackage(Context& context,
                                     SemIR::TypeId namespace_type_id,
                                     SemIR::InstId import_decl_id,
                                     PackageNameId package_id,
                                     llvm::ArrayRef<SemIR::ImportIR> import_irs,
                                     bool has_load_error) -> void;

// Given a name scope that corresponds to another package (having one or more
// `import_irs`), looks for the name in imports. Name resolution results are
// added to the scope, and the `InstId` (possibly `None`) is returned.
//
// In general, this will add an `ImportRef` and load it; it's never left
// unloaded because the result is expected to be immediately used. Namespaces
// will be directly produced, similar to how they function for imports from the
// current package. Conflicts will be resolved and diagnosed.
//
// Arguments are all in the context of the current IR. Scope lookup is expected
// to be resolved first.
auto ImportNameFromOtherPackage(
    Context& context, SemIRLoc loc, SemIR::NameScopeId scope_id,
    llvm::ArrayRef<std::pair<SemIR::ImportIRId, SemIR::NameScopeId>>
        import_ir_scopes,
    SemIR::NameId name_id) -> SemIR::InstId;

}  // namespace Carbon::Check

#endif  // CARBON_TOOLCHAIN_CHECK_IMPORT_H_