Implement lowering of AST::TupleStructItemsHasRest

gcc/rust/ChangeLog:

	* hir/rust-ast-lower-pattern.cc (ASTLoweringPattern::visit(TupleStructPattern)):
	Implement lowering of AST::TupleStructItemsHasRest to HIR.
	* typecheck/rust-hir-type-check-pattern.cc (TypeCheckPattern::visit(TupleStructPattern)):
	Add the respective type checking for AST::TupleStructItemsHasRest
	* checks/errors/rust-hir-pattern-analysis.cc (lower_tuple_pattern):
	Add respective pattern for HAS_REST case.

Signed-off-by: Yap Zhi Heng <[email protected]>

Author: Polygonalr

gcc/rust/checks/errors/rust-hir-pattern-analysis.cc

@@ -1212,25 +1212,52 @@ lower_tuple_pattern (Resolver::TypeCheckContext *ctx,
     {
     case HIR::TupleStructItems::ItemType::NO_REST:
       {
-	HIR::TupleStructItemsNoRest &multiple
+	HIR::TupleStructItemsNoRest &items_no_rest
 	  = static_cast<HIR::TupleStructItemsNoRest &> (elems);
 
 	rust_assert (variant->get_fields ().size ()
-		     == multiple.get_patterns ().size ());
+		     == items_no_rest.get_patterns ().size ());
 
-	for (size_t i = 0; i < multiple.get_patterns ().size (); i++)
+	for (size_t i = 0; i < items_no_rest.get_patterns ().size (); i++)
 	  {
 	    fields.push_back (
-	      lower_pattern (ctx, *multiple.get_patterns ().at (i),
+	      lower_pattern (ctx, *items_no_rest.get_patterns ().at (i),
 			     variant->get_fields ().at (i)->get_field_type ()));
 	  }
 	return DeconstructedPat (ctor, arity, fields, pattern.get_locus ());
       }
       break;
     case HIR::TupleStructItems::ItemType::HAS_REST:
       {
-	// TODO: ranged tuple struct items
-	rust_unreachable ();
+	HIR::TupleStructItemsHasRest &items_has_rest
+	  = static_cast<HIR::TupleStructItemsHasRest &> (elems);
+
+	size_t num_patterns = items_has_rest.get_lower_patterns ().size ()
+			      + items_has_rest.get_upper_patterns ().size ();
+
+	rust_assert (num_patterns <= variant->num_fields ());
+
+	size_t i = 0;
+	for (auto &pattern_member : items_has_rest.get_lower_patterns ())
+	  {
+	    fields.push_back (lower_pattern (
+	      ctx, *pattern_member,
+	      variant->get_fields ().at (i++)->get_field_type ()));
+	  }
+	while (i < variant->num_fields ()
+		     - items_has_rest.get_upper_patterns ().size ())
+	  {
+	    fields.push_back (
+	      DeconstructedPat::make_wildcard (pattern.get_locus ()));
+	    i++;
+	  }
+	for (auto &pattern_member : items_has_rest.get_upper_patterns ())
+	  {
+	    fields.push_back (lower_pattern (
+	      ctx, *pattern_member,
+	      variant->get_fields ().at (i++)->get_field_type ()));
+	  }
+	return DeconstructedPat (ctor, arity, fields, pattern.get_locus ());
       }
       break;
     default:

gcc/rust/hir/rust-ast-lower-pattern.cc

@@ -83,20 +83,39 @@ ASTLoweringPattern::visit (AST::TupleStructPattern &pattern)
     {
     case AST::TupleStructItems::HAS_REST:
       {
-	// TODO
-	rust_unreachable ();
+	AST::TupleStructItemsHasRest &items_has_rest
+	  = static_cast<AST::TupleStructItemsHasRest &> (items);
+
+	std::vector<std::unique_ptr<HIR::Pattern>> lower_patterns;
+	lower_patterns.reserve (items_has_rest.get_lower_patterns ().size ());
+	for (auto &pattern_member : items_has_rest.get_lower_patterns ())
+	  {
+	    lower_patterns.emplace_back (
+	      ASTLoweringPattern::translate (*pattern_member));
+	  }
+
+	std::vector<std::unique_ptr<HIR::Pattern>> upper_patterns;
+	upper_patterns.reserve (items_has_rest.get_upper_patterns ().size ());
+	for (auto &pattern_member : items_has_rest.get_upper_patterns ())
+	  {
+	    upper_patterns.emplace_back (
+	      ASTLoweringPattern::translate (*pattern_member));
+	  }
+
+	lowered = new HIR::TupleStructItemsHasRest (std::move (lower_patterns),
+						    std::move (upper_patterns));
       }
       break;
 
     case AST::TupleStructItems::NO_REST:
       {
-	AST::TupleStructItemsNoRest &items_no_range
+	AST::TupleStructItemsNoRest &items_no_rest
 	  = static_cast<AST::TupleStructItemsNoRest &> (items);
 
 	std::vector<std::unique_ptr<HIR::Pattern>> patterns;
-	patterns.reserve (items_no_range.get_patterns ().size ());
+	patterns.reserve (items_no_rest.get_patterns ().size ());
 
-	for (auto &inner_pattern : items_no_range.get_patterns ())
+	for (auto &inner_pattern : items_no_rest.get_patterns ())
 	  patterns.emplace_back (
 	    ASTLoweringPattern::translate (*inner_pattern));
 

gcc/rust/typecheck/rust-hir-type-check-pattern.cc

@@ -202,31 +202,73 @@ TypeCheckPattern::visit (HIR::TupleStructPattern &pattern)
     {
     case HIR::TupleStructItems::HAS_REST:
       {
-	// TODO
-	rust_unreachable ();
+	HIR::TupleStructItemsHasRest &items_has_rest
+	  = static_cast<HIR::TupleStructItemsHasRest &> (items);
+	size_t pattern_min_cap = items_has_rest.get_lower_patterns ().size ()
+				 + items_has_rest.get_upper_patterns ().size ();
+	if (variant->num_fields () < pattern_min_cap)
+	  {
+	    rust_error_at (pattern.get_locus (), ErrorCode::E0023,
+			   "this pattern has %lu fields but the corresponding "
+			   "tuple variant has %lu field",
+			   (unsigned long) (pattern_min_cap),
+			   (unsigned long) variant->num_fields ());
+	    // we continue on to try and setup the types as best we can for
+	    // type checking
+	  }
+
+	// iterate the fields manually to set them up
+	size_t i = 0;
+	for (auto &pattern : items_has_rest.get_lower_patterns ())
+	  {
+	    if (i >= variant->num_fields ())
+	      break;
+
+	    TyTy::StructFieldType *field = variant->get_field_at_index (i++);
+	    TyTy::BaseType *fty = field->get_field_type ();
+
+	    // setup the type on this pattern type
+	    context->insert_type (pattern->get_mappings (), fty);
+	    TypeCheckPattern::Resolve (*pattern, fty);
+	  }
+
+	i = variant->num_fields ()
+	    - items_has_rest.get_upper_patterns ().size ();
+	for (auto &pattern : items_has_rest.get_upper_patterns ())
+	  {
+	    if (i >= variant->num_fields ())
+	      break;
+
+	    TyTy::StructFieldType *field = variant->get_field_at_index (i++);
+	    TyTy::BaseType *fty = field->get_field_type ();
+
+	    // setup the type on this pattern type
+	    context->insert_type (pattern->get_mappings (), fty);
+	    TypeCheckPattern::Resolve (*pattern, fty);
+	  }
       }
       break;
 
     case HIR::TupleStructItems::NO_REST:
       {
-	HIR::TupleStructItemsNoRest &items_no_range
+	HIR::TupleStructItemsNoRest &items_no_rest
 	  = static_cast<HIR::TupleStructItemsNoRest &> (items);
 
-	if (items_no_range.get_patterns ().size () != variant->num_fields ())
+	if (items_no_rest.get_patterns ().size () != variant->num_fields ())
 	  {
 	    rust_error_at (
 	      pattern.get_locus (), ErrorCode::E0023,
 	      "this pattern has %lu fields but the corresponding "
 	      "tuple variant has %lu field",
-	      (unsigned long) items_no_range.get_patterns ().size (),
+	      (unsigned long) items_no_rest.get_patterns ().size (),
 	      (unsigned long) variant->num_fields ());
 	    // we continue on to try and setup the types as best we can for
 	    // type checking
 	  }
 
 	// iterate the fields and set them up, I wish we had ZIP
 	size_t i = 0;
-	for (auto &pattern : items_no_range.get_patterns ())
+	for (auto &pattern : items_no_rest.get_patterns ())
 	  {
 	    if (i >= variant->num_fields ())
 	      break;