Migrate error state to optionals

gcc/rust/ChangeLog:

	* ast/rust-ast-builder.cc (Builder::self_ref_param): Remove error state
	and use optional.
	* ast/rust-ast-visitor.cc (DefaultASTVisitor::visit): Check label
	before visiting.
	* ast/rust-ast.cc (ContinueExpr::as_string): Retrieve label value.
	(Lifetime::as_string): Retrieve lifetime value.
	(ReferenceType::as_string): Likewise.
	(SelfParam::as_string): Likewise.
	* ast/rust-ast.h: Remove lifetime and LifetimeParam error state.
	* ast/rust-desugar-for-loops.cc (DesugarForLoops::DesugarCtx::make_break_arm):
	Use optional instead of error state.
	* ast/rust-expr.h (class ContinueExpr): Make label optional.
	* ast/rust-item.h (class SelfParam): Make lifetime optional.
	* ast/rust-type.h (class ReferenceType): Likewise.
	* backend/rust-compile-base.cc: Use optional for self param instead
	of error state.
	* backend/rust-compile-base.h: Update function prototype.
	* expand/rust-derive-clone.cc (DeriveClone::clone_fn): Use optional.
	* hir/rust-ast-lower-base.cc (ASTLoweringBase::lower_self): Lower
	lifetime only if it exists.
	* hir/rust-ast-lower-block.h: Lower loop label only if it exists.
	* hir/rust-ast-lower-expr.cc (ASTLoweringExpr::visit): Likewise.
	* hir/rust-ast-lower-implitem.cc (ASTLowerImplItem::visit): Remove
	references to error state.
	(ASTLowerTraitItem::visit): Lower self param only if it exists.
	* hir/rust-ast-lower-item.cc (ASTLoweringItem::visit): Use nullopt
	for default value instead of SelfParam error state.
	* hir/rust-ast-lower.cc (ASTLoweringExprWithBlock::visit): Lower label
	only if it exists.
	* hir/rust-hir-dump.cc (Dump::do_traitfunctiondecl): Print self only if
	it exists.
	(Dump::visit): Liewise.
	* hir/tree/rust-hir-bound.h: Remove error state.
	* hir/tree/rust-hir-expr.cc (ContinueExpr::ContinueExpr): Use optional
	in constructor for loop label.
	(BreakExpr::BreakExpr): Likewise.
	* hir/tree/rust-hir-expr.h (class ContinueExpr): Remove error state
	implementation.
	(class BreakExpr): Likewise.
	* hir/tree/rust-hir-generic-param.h: Likewise.
	* hir/tree/rust-hir-item.cc (SelfParam::SelfParam): Make lifetime
	optional.
	(Function::Function): Make self param optional.
	* hir/tree/rust-hir-item.h (class Function): Likewise.
	* hir/tree/rust-hir-type.cc (ReferenceType::ReferenceType): Make
	lifetime optional.
	* hir/tree/rust-hir-type.h (class ReferenceType): Likewise.
	* hir/tree/rust-hir.cc (ContinueExpr::as_string): Use new getter.
	(BreakExpr::as_string): Likewise.
	(Lifetime::as_string): Likewise.
	(ReferenceType::as_string): Likewise.
	(TraitFunctionDecl::as_string): Likewise.
	(SelfParam::as_string): Remove error state checking.
	* parse/rust-parse-impl.h (Parser::parse_generic_param): Adapt to
	optional.
	(Parser::parse_lifetime_params): Likewise.
	(Parser::parse_lifetime_params_objs): Likewise.
	(Parser::parse_lifetime_param): Likewise.
	(Parser::parse_lifetime_where_clause_item): Likewise.
	(Parser::parse_type_param_bound): Likewise.
	(Parser::parse_lifetime_bounds): Likewise.
	(Parser::parse_path_generic_args): Likewise.
	(Parser::parse_self_param): Likewise.
	(Parser::parse_break_expr): Likewise.
	(Parser::parse_continue_expr): Likewise.
	(Parser::parse_reference_type_inner): Likewise.
	* parse/rust-parse.h (class ParseLifetimeParamError): Add new class for
	lifetime param parsing errors.
	(class ParseLifetimeError): Add new class for lifetime parsing errors.
	(enum ParseSelfError): Add new class for self param parsing errors.
	* typecheck/rust-hir-type-check-implitem.cc (TypeCheckImplItem::visit):
	Use unchecked getter in checked context. And make anonymous region.
	* typecheck/rust-hir-type-check.cc (TraitItemReference::get_type_from_fn):
	Likewise.

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

1 files changed, 7 insertions, 3 deletions

diff --git a/gcc/rust/hir/rust-ast-lower-expr.cc b/gcc/rust/hir/rust-ast-lower-expr.cc
index 575eea6..7bb7320 100644
--- a/gcc/rust/hir/rust-ast-lower-expr.cc
+++ b/gcc/rust/hir/rust-ast-lower-expr.cc
@@ -597,8 +597,10 @@ ASTLoweringExpr::visit (AST::ForLoopExpr &expr)
 void
 ASTLoweringExpr::visit (AST::BreakExpr &expr)
 {
-  HIR::Lifetime break_label
-    = lower_lifetime (expr.get_label ().get_lifetime ());
+  tl::optional<HIR::Lifetime> break_label = tl::nullopt;
+  if (expr.has_label ())
+    break_label = lower_lifetime (expr.get_label ().get_lifetime ());
+
   HIR::Expr *break_expr
     = expr.has_break_expr ()
 	? ASTLoweringExpr::translate (expr.get_break_expr ())
@@ -618,7 +620,9 @@ ASTLoweringExpr::visit (AST::BreakExpr &expr)
 void
 ASTLoweringExpr::visit (AST::ContinueExpr &expr)
 {
-  HIR::Lifetime break_label = lower_lifetime (expr.get_label ());
+  tl::optional<HIR::Lifetime> break_label;
+  if (expr.has_label ())
+    break_label = lower_lifetime (expr.get_label ());
 
   auto crate_num = mappings.get_current_crate ();
   Analysis::NodeMapping mapping (crate_num, expr.get_node_id (),