Description

JelleZijlstra

opened on May 17, 2023

Issue body actions

Before:

>>> type A[T: (x:=3)] = int
  File "<stdin>", line 1
SyntaxError: 'named expression' can not be used within a TypeVar bound

After:

>>> type A[T: (x:=3)] = int
  File "<stdin>", line 1
SyntaxError: named expression cannot be used within a TypeVar bound

("cannot" is one word; the quotes don't really make sense here)

Linked PRs

• gh-104572: Improve error messages for invalid constructs in PEP 695 contexts #104573

Activity

1. JelleZijlstra

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   topic-typing

   on May 17, 2023
2. JelleZijlstra

   self-assigned this

   on May 17, 2023
3. JelleZijlstra

   added a commit that references this issue on May 17, 2023

   pythongh-104572: Improve error messages for invalid constructs in PEP…

   9daa1af
4. JelleZijlstra commented on May 17, 2023

   

   JelleZijlstra

   on May 17, 2023

   MemberAuthor

   More actions

   It would also be nice if the error display had a ^ pointing to the precise location. Unfortunately that appears to be difficult, as the error is raised in symtable.c where we no longer have access to the original source. The same thing happens with other syntax errors raised in symtable.c:

   >>> def f(a, a): pass
   ... 
     File "<stdin>", line 1
   SyntaxError: duplicate argument 'a' in function definition
   
5. terryjreedy commented on May 17, 2023

   

   terryjreedy

   on May 17, 2023

   Member

   More actions

   The quotes might have come from thinking of 'named expression' as a grammar target, but then it would have to really be in the doc grammar and would need a hyphen. Error messages should save quotes for quotes from the code, as with 'a' above.
6. JelleZijlstra

   added a commit that references this issue on May 17, 2023

   gh-104572: Improve error messages for invalid constructs in PEP 695 c…

   97db2f3
7. carljm

   added a commit that references this issue on May 17, 2023

   Merge branch 'main' into 709funconly

   b1bb3a7
8. AlexWaygood

   closed this as completedon May 17, 2023
9. JelleZijlstra

   added a commit that references this issue on May 18, 2023

   pythongh-104572: Improve error messages for invalid constructs in PEP…

   dc957c7

Issue actions