temporary fix "Cannot read property symbol of undefined"

Author: Tam Nguyen

lib/tsserver.js

@@ -106106,7 +106106,7 @@ var ts;
                         // If the symbol/moduleSymbol was a merged symbol, it will have a new identity
                         // in the checker, even though the symbols to merge are the same (guaranteed by
                         // cache invalidation in synchronizeHostData).
-                        if (suggestion.symbol.declarations) {
+                        if (suggestion.symbol.declarations && suggestion.symbol.declarations[0]) {
                             suggestion.symbol = checker.getMergedSymbol(suggestion.origin.isDefaultExport
                                 ? suggestion.symbol.declarations[0].localSymbol || suggestion.symbol.declarations[0].symbol
                                 : suggestion.symbol.declarations[0].symbol);