Interpolation and type-stability improvements (#105)
* Interpolation and type-stability improvements
Should be a quick fix for #94. Also improve the interpolation algorithm:
instead of starting with a copy of the AST and re-scanning the tree for
interpolations with each call to `_interpolate_ast`, do one full
unconditional pass over the initial tree that copies and interpolates.
Also fixes interpolation into QuoteNode in expr compat mode (e.g. `@eval Base.$x`)
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Co-authored-by: Claire Foster <aka.c42f@gmail.com>
