Customer scenario

Customer has a string concatenation where the string literal contains curly braces. For example:

var firstExample = "Something {X} = " + 9;
var secondExample = "Something {" + 9 + "}";

Using the "Convert to interpolated string" refactoring does not escape the curly braces in the string literal(s). When applying the refactoring, this can lead to compile errors or unmeant escapes:

// results as of now:
var firstExample = $"Something {X} = {9}"; // compile error: {X} does not exist in context
var secondExample = $"Something {{9}}"; // '9' is escaped when it should not be

Bugs this fixes

#23536

Workarounds, if any

Escape the braces manually in the string literal(s) before or after applying the refactoring.

Risk

The scope of the fix is limited to this specific refactoring.

Performance impact

Low, the fix only adds two extra string operations (which are only executed if necessary).

Is this a regression from a previous update?

I don't know.

Root cause analysis

This specific situation was not covered by unit tests yet. I added these tests now.

How was the bug found?

Customer reported, see #23536.

Test documentation updated?

No impact on test documentation.