With this SQL:

/* This is a comment */
CREATE DEFAULT [dbo].[valueZero] AS 0;


CREATE TABLE [dbo].[A] (
  id INT IDENTITY,
  val INT NOT NULL
);

sp_bindefault '[dbo].[valueZero]', '[dbo].[A].[val]'

(Make sure that the comment in line 1 is included when you create the default, in DBeaver for example by selecting both lines before executing the statement.)

db pull will crash on Introspection:

✖ Introspecting based on datasource defined in prisma\schema.prisma

Oops, an unexpected error occurred!
Error in Schema engine.
Reason: [schema-engine\sql-schema-describer\src\mssql.rs:348:30] called `Result::unwrap()` on an `Err` value: "Couldn't parse default value: `/* This is a comment */\r\nCREATE DEFAULT [dbo].[valueZero] AS 0;\r\n`"

The underlying Introspection query is this one:
https://github.com/prisma/prisma-engines/blob/b4fe3e61b0e65aba302a47e5e94bf961f6ef2fc2/schema-engine/sql-schema-describer/src/mssql.rs#L268C13-L290C81
The gist of it is this simplified query:

SELECT OBJECT_DEFINITION(c.default_object_id)    
	FROM sys.columns c                     
  	INNER JOIN sys.objects obj ON c.object_id = obj.object_id
  	WHERE obj.is_ms_shipped = 0

The result:

(Note the line breaks in the string.)

Seems this case of the result being a multi-line string crashes our default parsing logic:
https://github.com/prisma/prisma-engines/blob/b4fe3e61b0e65aba302a47e5e94bf961f6ef2fc2/schema-engine/sql-schema-describer/src/mssql.rs#L340C1-L348C39