[PATCH 1/2] Avoid potential memory leak in Rust parser

[Tom Tromey <tromey@adacore.com>]

rust_parser::parse_field has some support for completion.  This code
allocates a rust_structop using plain 'new', then stores it somewhere.
However, between the allocation and the store, the function calls
"lex()", which might throw.  This would leak the rust_structop object.

This patch rearranges the code slightly to avoid the memory leak.
---
 gdb/rust-parse.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/gdb/rust-parse.c b/gdb/rust-parse.c
index db4122119a5..9aaf85dc81c 100644
--- a/gdb/rust-parse.c
+++ b/gdb/rust-parse.c
@@ -1544,17 +1544,18 @@ rust_parser::parse_field (operation_up &&lhs)
     case COMPLETE:
       {
 	bool is_complete = current_token == COMPLETE;
-	auto struct_op = new rust_structop (std::move (lhs),
-					    std::string (current_string_val));
+	auto struct_op
+	  = std::make_unique<rust_structop> (std::move (lhs),
+					     std::string (current_string_val));
 	lex ();
 	if (is_complete)
 	  {
-	    completion_op.reset (struct_op);
-	    pstate->mark_struct_expression (struct_op);
+	    pstate->mark_struct_expression (struct_op.get ());
+	    completion_op = std::move (struct_op);
 	    /* Throw to the outermost level of the parser.  */
 	    error (_("not really an error"));
 	  }
-	result.reset (struct_op);
+	result = std::move (struct_op);
       }
       break;
 

-- 
2.56.0