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Postfix adjustment hints # Basic Description This PR implements "postfix" adjustment hints:  They are identical to normal adjustment hints, but are rendered _after_ the expression. E.g. `expr.*` instead of `*expr`. ~~This mirrors "postfix deref" feature that I'm planning to eventually propose to the compiler.~~ # Motivation The advantage of being postfix is that you need to add parentheses less often:   This is because a lot of "reborrow" hints are caused by field access or method calls, both of which are postfix and have higher "precedence" than prefix `&` and `*`. Also IMHO it just looks nicer and it's more clear what is happening (order of operations). # Modes However, there are some cases where postfix hints need parentheses but prefix don't (for example `&x` being turned into `(&x).*.*.&` or `&**&x`). This PR allows users to choose which look they like more. There are 4 options (`rust-analyzer.inlayHints.expressionAdjustmentHints.mode` setting): - `prefix` — always use prefix hints (default, what was used before that PR) - `postfix` — always use postfix hints - `prefer_prefix` — try to minimize number of parentheses, breaking ties in favor of prefix - `prefer_postfix` — try to minimize number of parentheses, breaking ties in favor of postfix Comparison of all modes:     # Edge cases Where are some rare cases where chain hints weirdly interact with adjustment hints, for example (note `SourceAnalyzer.&`):  This is pre-existing, you can get the same effect with prefix hints (`SourceAnalyzer)`). ---- Another weird thing is this:  Here `.&` is a hint and `?` is written in the source code. It looks like `?` is part of the hint because `?.` is ligature in my font. IMO this is a bug in vscode, but still worth mentioning (I'm also too lazy to report it there...). # Fixed bugs I've used the "needs parens" API and this accidentally fixed a bug with parens around `as`, see the test diff: ```diff,rust let _: *const u32 = &mut 0u32 as *mut u32; //^^^^^^^^^^^^^^^^^^^^^<mut-ptr-to-const-ptr> + //^^^^^^^^^^^^^^^^^^^^^( + //^^^^^^^^^^^^^^^^^^^^^) ... let _: *const u32 = &mut 0u32 as *mut u32; //^^^^^^^^^^^^^^^^^^^^^<mut-ptr-to-const-ptr> + //^^^^^^^^^^^^^^^^^^^^^( + //^^^^^^^^^^^^^^^^^^^^^) ``` # Changelog changelog feature Add an option to make adjustment hints (aka reborrow hints) postfix changelog fix Fix placement of parentheses around `as` casts for adjustment hints
