Fix error() method that throws when done() is true

When done() is true last correct token and its position is printed.

Author: filipsajdak

source/parse.h

@@ -2756,16 +2756,31 @@ class parser
         -> void
     {
         auto m = std::string{msg};
-        if (include_curr_token) {
-            m += std::string(" (at '") + curr().to_string(true) + "')";
-        }
-        if (
-            err_pos == source_position{}
-            && peek(0)
-            )
-        {
-            err_pos = peek(0)->position();
+
+        if (done()) {
+            int i = 0;
+            while(!peek(i) && pos + i > 0) { --i; };
+            if (peek(i)) {
+                m += std::string(" (after '") + peek(i)->to_string(true) + "')";
+                if (
+                    err_pos == source_position{}
+                ) {
+                    err_pos = peek(i)->position();
+                }
+            }
+        } else {
+            if (include_curr_token) {
+                m += std::string(" (at '") + curr().to_string(true) + "')";
+            }
+            if (
+                err_pos == source_position{}
+                && peek(0)
+                )
+            {
+                err_pos = peek(0)->position();
+            }
         }
+
         errors.emplace_back( err_pos, m, false, fallback );
     }
 
@@ -4777,7 +4792,8 @@ class parser
 
         //  If there's no [ [ then this isn't a contract
         if (
-            curr().type() != lexeme::LeftBracket
+            done()
+            || curr().type() != lexeme::LeftBracket
             || !peek(1)
             || peek(1)->type() != lexeme::LeftBracket
             )