[3.9] bpo-44322: Document more SyntaxError details. (GH-26562)

1. SyntaxError args have a tuple of other attributes. 2. Attributes are adjusted for errors in f-string field expressions. 3. Compile() can raise SyntaxErrors. (cherry picked from commit 67dfa6f)

Author: terryjreedy

Doc/library/exceptions.rst

@@ -390,14 +390,16 @@ The following exceptions are the exceptions that are usually raised.
 
  .. versionadded:: 3.5
 
-.. exception:: SyntaxError
+.. exception:: SyntaxError(message, details)
 
  Raised when the parser encounters a syntax error. This may occur in an
- :keyword:`import` statement, in a call to the built-in functions :func:`exec`
+ :keyword:`import` statement, in a call to the built-in functions
+ :func:`compile`, :func:`exec`,
  or :func:`eval`, or when reading the initial script or standard input
  (also interactively).
 
  The :func:`str` of the exception instance returns only the error message.
+ Details is a tuple whose members are also available as separate attributes.
 
  .. attribute:: filename
 
@@ -417,6 +419,11 @@ The following exceptions are the exceptions that are usually raised.
 
  The source code text involved in the error.
 
+ For errors in f-string fields, the message is prefixed by "f-string: "
+ and the offsets are offsets in a text constructed from the replacement
+ expression. For example, compiling f'Bad {a b} field' results in this
+ args attribute: ('f-string: ...', ('', 1, 4, '(a b)\n')).
+
 
 .. exception:: IndentationError
 

Misc/NEWS.d/next/Documentation/2021-06-06-14-12-00.bpo-44322.K0PHfE.rst

@@ -0,0 +1,2 @@
+Document that SyntaxError args have a details tuple and that details are
+adjusted for errors in f-string field replacement expressions.