Auto merge of #85993 - bjorn3:serde_json, r=wesleywiser

Remove all json handling from rustc_serialize

Json is now handled using serde_json. Where appropriate I have replaced json usage with binary serialization (rmeta files) or manual string formatting (emcc linker arg generation).

This allowed for removing and simplifying a lot of code, which hopefully results in faster serialization/deserialization and faster compiles of rustc itself.

Where sensible we now use serde. Metadata and incr cache serialization keeps using a heavily modified (compared to crates.io) rustc-serialize version that in the future could probably be extended with zero-copy deserialization or other perf tricks that serde can't support due to supporting more than one serialization format.

Note that I had to remove `-Zast-json` and `-Zast-json-noexpand` as the relevant AST types don't implement `serde::Serialize`.

Fixes #40177

See also https://github.com/rust-lang/compiler-team/issues/418

1 files changed, 0 insertions, 10 deletions

diff --git a/src/test/ui/ast-json/ast-json-output.rs b/src/test/ui/ast-json/ast-json-output.rs
deleted file mode 100644
index 2e009149ed6..00000000000
--- a/src/test/ui/ast-json/ast-json-output.rs
+++ /dev/null
@@ -1,10 +0,0 @@
-// Check that AST json printing works.
-#![crate_type = "lib"]
-
-// check-pass
-// compile-flags: -Zast-json
-// normalize-stdout-test ":\d+" -> ":0"
-
-// Only include a single item to reduce how often the test output needs
-// updating.
-extern crate core;