Replace unique_ptr references with references

This kind of double indirection is pointless and prone to error. This
commit change the api of all getters from the AST to use references
directly instead of references to unique pointers.

gcc/rust/ChangeLog:

	* ast/rust-ast-collector.cc (TokenCollector::visit): Remove reference
	to unique pointer and replace it with a direct reference to the wrapped
	data.
	* ast/rust-ast.cc (VariadicParam::as_string): Likewise.
	(BlockExpr::normalize_tail_expr): Likewise.
	* ast/rust-expr.h: Likewise and add pointer getter in order to allow
	pointer reseat.
	* ast/rust-item.h: Likewise and add pointer getter for reseat.
	* ast/rust-path.h: Likewise.
	* ast/rust-pattern.h: Likewise.
	* ast/rust-stmt.h: Likewise.
	* ast/rust-type.h: Likewise.
	* expand/rust-cfg-strip.cc (CfgStrip::maybe_strip_struct_fields):
	Remove references to unique pointers and replace it with direct
	references to the wrapped object.
	(CfgStrip::maybe_strip_tuple_fields): Likewise.
	(CfgStrip::maybe_strip_generic_args): Likewise.
	(CfgStrip::maybe_strip_qualified_path_type): Likewise.
	(CfgStrip::visit): Likewise.
	* expand/rust-expand-visitor.cc (ExpandVisitor::maybe_expand_expr):
	Likewise.
	(ExpandVisitor::maybe_expand_type): Likewise.
	(ExpandVisitor::visit): Likewise.
	* expand/rust-expand-visitor.h: Likewise.
	* hir/rust-ast-lower-base.cc (ASTLoweringBase::lower_binding):
	Likewise.
	(ASTLoweringBase::lower_generic_args): Likewise.
	(ASTLoweringBase::lower_self): Likewise.
	(ASTLoweringBase::lower_type_no_bounds): Likewise.
	(ASTLoweringBase::lower_bound): Likewise.
	(ASTLoweringBase::lower_range_pattern_bound): Likewise.
	* hir/rust-ast-lower-base.h: Likewise.
	* hir/rust-ast-lower-block.h: Likewise.
	* hir/rust-ast-lower-enumitem.h: Likewise.
	* hir/rust-ast-lower-expr.cc (ASTLoweringExpr::translate): Likewise.
	(ASTLoweringExpr::visit): Likewise.
	* hir/rust-ast-lower-expr.h: Likewise.
	* hir/rust-ast-lower-extern.h: Likewise.
	* hir/rust-ast-lower-implitem.cc (ASTLowerImplItem::translate):
	Likewise.
	(ASTLowerImplItem::visit): Likewise.
	(ASTLowerTraitItem::translate): Likewise.
	(ASTLowerTraitItem::visit): Likewise.
	* hir/rust-ast-lower-implitem.h: Likewise.
	* hir/rust-ast-lower-item.cc (ASTLoweringItem::translate): Likewise.
	(ASTLoweringItem::visit): Likewise.
	* hir/rust-ast-lower-item.h: Likewise.
	* hir/rust-ast-lower-pattern.cc (ASTLoweringPattern::translate):
	Likewise.
	(ASTLoweringPattern::visit): Likewise.
	* hir/rust-ast-lower-pattern.h: Likewise.
	* hir/rust-ast-lower-stmt.cc (ASTLoweringStmt::visit): Likewise.
	* hir/rust-ast-lower-struct-field-expr.h: Likewise.
	* hir/rust-ast-lower-type.cc (ASTLowerTypePath::visit): Likewise.
	(ASTLowerQualifiedPathInType::visit): Likewise.
	(ASTLoweringType::translate): Likewise.
	(ASTLoweringType::visit): Likewise.
	(ASTLowerGenericParam::translate): Likewise.
	(ASTLowerGenericParam::visit): Likewise.
	(ASTLoweringTypeBounds::translate): Likewise.
	(ASTLoweringTypeBounds::visit): Likewise.
	(ASTLowerWhereClauseItem::visit): Likewise.
	* hir/rust-ast-lower-type.h: Likewise.
	* hir/rust-ast-lower.cc (ASTLowering::go): Likewise.
	(ASTLoweringBlock::visit): Likewise.
	(ASTLoweringIfBlock::visit): Likewise.
	(ASTLoweringIfLetBlock::visit): Likewise.
	(ASTLowerStructExprField::visit): Likewise.
	(ASTLoweringExprWithBlock::visit): Likewise.
	(ASTLoweringBase::lower_qual_path_type): Likewise.
	(ASTLoweringBase::lower_closure_param): Likewise.
	* resolve/rust-ast-resolve-base.cc (ResolverBase::resolve_visibility):
	Likewise.
	* resolve/rust-ast-resolve-expr.cc (ResolveExpr::go): Likewise.
	(ResolveExpr::visit): Likewise.
	(ResolveExpr::resolve_closure_param): Likewise.
	* resolve/rust-ast-resolve-expr.h: Likewise.
	* resolve/rust-ast-resolve-implitem.h: Likewise.
	* resolve/rust-ast-resolve-item.cc (ResolveTraitItems::visit):
	Likewise.
	(ResolveItem::go): Likewise.
	(ResolveItem::visit): Likewise.
	(ResolveItem::resolve_impl_item): Likewise.
	(ResolveItem::resolve_extern_item): Likewise.
	(ResolveImplItems::go): Likewise.
	(ResolveExternItem::go): Likewise.
	(ResolveExternItem::visit): Likewise.
	* resolve/rust-ast-resolve-item.h: Likewise.
	* resolve/rust-ast-resolve-path.cc (ResolvePath::go): Likewise.
	(ResolvePath::resolve_path): Likewise.
	* resolve/rust-ast-resolve-path.h: Likewise.
	* resolve/rust-ast-resolve-pattern.cc (PatternDeclaration::go):
	Likewise.
	(PatternDeclaration::visit): Likewise.
	(resolve_range_pattern_bound): Likewise.
	* resolve/rust-ast-resolve-pattern.h: Likewise.
	* resolve/rust-ast-resolve-stmt.cc (ResolveStmt::visit): Likewise.
	* resolve/rust-ast-resolve-stmt.h: Likewise.
	* resolve/rust-ast-resolve-struct-expr-field.cc (ResolveStructExprField::go):
	Likewise.
	(ResolveStructExprField::visit): Likewise.
	* resolve/rust-ast-resolve-struct-expr-field.h: Likewise.
	* resolve/rust-ast-resolve-toplevel.h: Likewise.
	* resolve/rust-ast-resolve-type.cc (ResolveType::visit): Likewise.
	(ResolveRelativeTypePath::go): Likewise.
	(ResolveRelativeQualTypePath::resolve_qual_seg): Likewise.
	(ResolveTypeToCanonicalPath::go): Likewise.
	(ResolveTypeToCanonicalPath::visit): Likewise.
	(ResolveGenericArgs::resolve_disambiguated_generic): Likewise.
	(ResolveGenericArgs::go): Likewise.
	* resolve/rust-ast-resolve-type.h: Likewise.
	* resolve/rust-ast-resolve.cc (NameResolution::go): Likewise.
	* resolve/rust-default-resolver.cc (DefaultResolver::visit): Likewise.
	* resolve/rust-early-name-resolver.cc (EarlyNameResolver::resolve_qualified_path_type):
	Likewise.
	(EarlyNameResolver::visit): Likewise.
	* resolve/rust-toplevel-name-resolver-2.0.cc (TopLevel::visit):
	Likewise.
	* checks/errors/rust-ast-validation.cc: Likewise.

Signed-off-by: Pierre-Emmanuel Patry <[email protected]>

gcc/rust/ast/rust-ast-collector.cc

@@ -2546,8 +2546,7 @@ TokenCollector::visit (LetStmt &stmt)
 {
   push (Rust::Token::make (LET, stmt.get_locus ()));
   auto &pattern = stmt.get_pattern ();
-  if (pattern)
-    visit (pattern);
+  visit (pattern);
 
   if (stmt.has_type ())
     {

gcc/rust/ast/rust-ast.cc

@@ -2291,7 +2291,7 @@ std::string
 VariadicParam::as_string () const
 {
   if (has_pattern ())
-    return get_pattern ()->as_string () + " : ...";
+    return get_pattern ().as_string () + " : ...";
   else
     return "...";
 }
@@ -4258,7 +4258,7 @@ BlockExpr::normalize_tail_expr ()
 
 	  if (!stmt.is_semicolon_followed ())
 	    {
-	      expr = std::move (stmt.get_expr ());
+	      expr = std::move (stmt.take_expr ());
 	      statements.pop_back ();
 	    }
 	}