gccrs: Change lookup_hir_implitem return type

Wrap the return type within an optional. Now return the parent id within
a pair instead of taking an out reference.

gcc/rust/ChangeLog:

	* backend/rust-compile-item.cc (CompileItem::visit): Change call site
	to accept new return type.
	* backend/rust-compile-resolve-path.cc (HIRCompileBase::query_compile):
	Likewise.
	* backend/rust-mangle-v0.cc (v0_path): Likewise.
	* checks/errors/rust-unsafe-checker.cc (UnsafeChecker::visit):
	Likewise.
	* checks/lints/rust-lint-marklive.cc (MarkLive::go): Likewise.
	(MarkLive::visit): Likewise.
	* typecheck/rust-type-util.cc (query_type): Likewise.
	* util/rust-hir-map.cc (Mappings::insert_hir_implitem): Likewise.
	(Mappings::lookup_hir_implitem): Change return type.
	* util/rust-hir-map.h: Update the function's prototype.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

3 files changed, 10 insertions, 19 deletions

diff --git a/gcc/rust/backend/rust-compile-item.cc b/gcc/rust/backend/rust-compile-item.cc
index 9d65b61..e7b3a17 100644
--- a/gcc/rust/backend/rust-compile-item.cc
+++ b/gcc/rust/backend/rust-compile-item.cc
@@ -152,15 +152,12 @@ CompileItem::visit (HIR::Function &function)
     {
       // if this is part of a trait impl block which is not generic we need to
       // ensure associated types are setup
-      HirId parent_impl_block = UNKNOWN_HIRID;
       HirId id = function.get_mappings ().get_hirid ();
-      HIR::ImplItem *impl_item
-	= ctx->get_mappings ().lookup_hir_implitem (id, &parent_impl_block);
-      if (impl_item != nullptr)
+      if (auto impl_item = ctx->get_mappings ().lookup_hir_implitem (id))
 	{
 	  Resolver::AssociatedImplTrait *impl = nullptr;
 	  bool found = ctx->get_tyctx ()->lookup_associated_trait_impl (
-	    parent_impl_block, &impl);
+	    impl_item->second, &impl);
 	  if (found)
 	    impl->setup_raw_associated_types ();
 	}
diff --git a/gcc/rust/backend/rust-compile-resolve-path.cc b/gcc/rust/backend/rust-compile-resolve-path.cc
index c27074f..7c9b303 100644
--- a/gcc/rust/backend/rust-compile-resolve-path.cc
+++ b/gcc/rust/backend/rust-compile-resolve-path.cc
@@ -238,18 +238,14 @@ HIRCompileBase::query_compile (HirId ref, TyTy::BaseType *lookup,
 	    }
 	}
 
-      HirId parent_impl_id = UNKNOWN_HIRID;
-      HIR::ImplItem *resolved_item
-	= ctx->get_mappings ().lookup_hir_implitem (ref, &parent_impl_id);
-      bool is_impl_item = resolved_item != nullptr;
-      if (is_impl_item)
+      if (auto resolved_item = ctx->get_mappings ().lookup_hir_implitem (ref))
 	{
 	  if (!lookup->has_substitutions_defined ())
-	    return CompileInherentImplItem::Compile (resolved_item, ctx,
+	    return CompileInherentImplItem::Compile (resolved_item->first, ctx,
 						     nullptr, true, expr_locus);
 	  else
-	    return CompileInherentImplItem::Compile (resolved_item, ctx, lookup,
-						     true, expr_locus);
+	    return CompileInherentImplItem::Compile (resolved_item->first, ctx,
+						     lookup, true, expr_locus);
 	}
       else
 	{
diff --git a/gcc/rust/backend/rust-mangle-v0.cc b/gcc/rust/backend/rust-mangle-v0.cc
index 0b6d945..261e844 100644
--- a/gcc/rust/backend/rust-mangle-v0.cc
+++ b/gcc/rust/backend/rust-mangle-v0.cc
@@ -384,17 +384,15 @@ v0_path (Rust::Compile::Context *ctx, const TyTy::BaseType *ty,
 
     auto hir_id = hid.value ();
 
-    HirId parent_impl_id = UNKNOWN_HIRID;
-    HIR::ImplItem *impl_item
-      = mappings.lookup_hir_implitem (hir_id, &parent_impl_id);
     HIR::Expr *expr = mappings.lookup_hir_expr (hir_id);
 
-    if (impl_item != nullptr)
+    if (auto impl_item = mappings.lookup_hir_implitem (hir_id))
       {
-	switch (impl_item->get_impl_item_type ())
+	switch (impl_item->first->get_impl_item_type ())
 	  {
 	    case HIR::ImplItem::FUNCTION: {
-	      HIR::Function *fn = static_cast<HIR::Function *> (impl_item);
+	      HIR::Function *fn
+		= static_cast<HIR::Function *> (impl_item->first);
 	      v0path
 		= v0_function_path (v0path, ctx, ty, fn->get_generic_params (),
 				    v0_identifier (seg.get ()));