fix: prevent access if properties couldn't be resolved when syntax highlighting in the REPL

PR-URL: #2412

Signed-off-by: Snehil Shah <snehilshah.989@gmail.com>
Reviewed-by: Philipp Burckhardt <pburckhardt@outlook.com>

Author: Snehil-Shah

lib/node_modules/@stdlib/repl/lib/tokenizer.js

@@ -270,6 +270,7 @@ function tokenizer( line, context ) {
 	function resolveMemberExpression( node, compute ) {
 		var properties = linkedList();
 		var property;
+		var computed;
 		var locals;
 		var obj;
 
@@ -350,7 +351,12 @@ function tokenizer( line, context ) {
 			}
 			// Case: `foo[a.b].bar` - recursively compute the internal `MemberExpression`...
 			if ( property.value.type === 'MemberExpression' ) {
-				obj = obj[ resolveMemberExpression( property.value, true ) ];
+				computed = resolveMemberExpression( property.value, true );
+				if ( !isLiteralType( typeof computed ) ) {
+					// Couldn't compute the internal `MemberExpression` into a definite name:
+					break;
+				}
+				obj = obj[ computed ];
 				if ( !obj ) {
 					// Property not found in context:
 					break;