Issue #20143: The line numbers reported in Argument Clinic errors are

now more accurate.

Misc/NEWS

@@ -16,6 +16,9 @@ Library
 Tools/Demos
 -----------
 
+- Issue #20143: The line numbers reported in Argument Clinic errors are
+  now more accurate.
+
 - Issue #20142: Py_buffer variables generated by Argument Clinic are now
   initialized with a default value.
 

Tools/clinic/clinic.py

@@ -943,8 +943,9 @@ class BlockParser:
                     fail("Checksum mismatch!\nExpected: {}\nComputed: {}".format(checksum, computed))
         else:
             # put back output
-            self.input.extend(reversed(output.splitlines(keepends=True)))
-            self.line_number -= len(output)
+            output_lines = output.splitlines(keepends=True)
+            self.line_number -= len(output_lines)
+            self.input.extend(reversed(output_lines))
             output = None
 
         return Block(input_output(), dsl_name, output=output)