Free of syn

Cargo.toml

@@ -7,7 +7,7 @@ homepage = "https://github.com/bevyengine/variadics_please"
 repository = "https://github.com/bevyengine/variadics_please"
 license = "MIT OR Apache-2.0"
 keywords = ["bevy", "variadics", "docs"]
-rust-version = "1.81.0"
+rust-version = "1.83.0"
 categories = ["rust-patterns"]
 exclude = ["tools/", ".github/"]
 documentation = "https://docs.rs/variadics_please"
@@ -20,9 +20,8 @@ alloc = []
 proc-macro = true
 
 [dependencies]
-syn = "2.0"
 quote = "1.0"
-proc-macro2 = "1.0"
+unsynn = "0.3"
 
 [dev-dependencies]
 static_assertions = "1.1"

RELEASES.md

@@ -1,5 +1,16 @@
 # `variadics_please` Release Notes
 
+## Unreleased
+
+- Switch from `syn` to `unsynn`
+  - [`syn` is known to be a major compile time bottleneck](https://fasterthanli.me/articles/the-virtue-of-unsynn). To improve the situation for users of `variadics_please`, we switched to `unsynn`, which is the alternative used by [`facet`](https://fasterthanli.me/articles/introducing-facet-reflection-for-rust).
+  - The compile time speedup depends on your local setup and the complexity of the macro invocation,
+    but on one test setup, the cold compilation time went from about 2.16 seconds to 0.56 seconds.
+  - The code generated by `variadics_please` should be identical to before.
+    Our Error messages may look a bit different now, but they should be just as readable.
+    If you encounter any weird behavior or diagnostics, let us know.
+  - Using `unsynn` bumps the MSRV from 1.81.0 to 1.83.0
+
 ## Version 1.1
 
 - added `all_tuples_enumerated`, which provides the index of each item in the tuple

deny.toml

@@ -20,6 +20,7 @@ allow = [
   "MIT-0",
   "Unlicense",
   "Zlib",
+  "Unicode-3.0",
 ]
 
 exceptions = [
@@ -73,6 +74,8 @@ deny = [
   { name = "android-activity", deny-multiple-versions = true },
   { name = "glam", deny-multiple-versions = true },
   { name = "raw-window-handle", deny-multiple-versions = true },
+  # keep syn entirely out of tree, since we use unsynn instead
+  { name = "syn" },
 ]
 
 [sources]