Fixes dotnet#54703. Spec change is at dotnet/csharplang#4910. Note that there is an interesting wrinkle here in that, for an interpolated string used as a string, the change in constant value makes the lowering mechanism an observable side effect. While doing this step during lowering instead of initial binding is technically feasible, it would be quite complex as there are several different ways an AppendLiteral call could get to lowering (dynamic, conversion to object, regular literal, passed by in, etc). For now, I'm opting for simple strategy of accepting this observable side-effect, and if we want to try and make that side effect invisble we can look at doing so at a later point.

Commits

Commits on Jul 9, 2021

Unescape interpolated string literal components

Refactor to calculate interpolation length based on unescaped string.

Remove blank line.

Fix mistake Chris caught by proxy.