1 files changed, 14 insertions, 0 deletions
diff --git a/Python/compile.c b/Python/compile.c
index cfe4b6e..a71e7d3 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -8976,6 +8976,16 @@ error:
     return -1;
 }
 
+static bool
+basicblock_has_lineno(const basicblock *bb) {
+    for (int i = 0; i < bb->b_iused; i++) {
+        if (bb->b_instr[i].i_lineno > 0) {
+            return true;
+        }
+    }
+    return false;
+}
+
 /* If this block ends with an unconditional jump to an exit block,
  * then remove the jump and extend this block with the target.
  */
@@ -8992,6 +9002,10 @@ extend_block(basicblock *bb) {
     }
     if (last->i_target->b_exit && last->i_target->b_iused <= MAX_COPY_SIZE) {
         basicblock *to_copy = last->i_target;
+        if (basicblock_has_lineno(to_copy)) {
+            /* copy only blocks without line number (like implicit 'return None's) */
+            return 0;
+        }
         last->i_opcode = NOP;
         for (int i = 0; i < to_copy->b_iused; i++) {
             int index = compiler_next_instr(bb);