Merge #6820

6820: Pass the crate environment to proc macros r=jonas-schievink a=jonas-schievink

In theory, fixes https://github.com/rust-analyzer/rust-analyzer/issues/6696.

This seems to result in these obscure crashes for some reason:

```
thread '<unnamed>' panicked at 'called `Option::unwrap()` on a `None` value', /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/scoped_cell.rs:75:51
stack backtrace:
   0: rust_begin_unwind
             at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/std/src/panicking.rs:483
   1: core::panicking::panic_fmt
             at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/core/src/panicking.rs:85
   2: core::panicking::panic
             at /rustc/7eac88abb2e57e752f3302f02be5f3ce3d7adfb4/library/core/src/panicking.rs:50
   3: core::option::Option<T>::unwrap
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/core/src/option.rs:383
   4: proc_macro::bridge::scoped_cell::ScopedCell<T>::replace
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/scoped_cell.rs:75
   5: proc_macro::bridge::client::BridgeState::with::{{closure}}
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:291
   6: std::thread::local::LocalKey<T>::try_with
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/local.rs:272
   7: std::thread::local::LocalKey<T>::with
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/local.rs:248
   8: proc_macro::bridge::client::BridgeState::with
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:290
   9: proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::with
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:329
  10: proc_macro::bridge::client::run_client::{{closure}}::{{closure}}
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:375
  11: proc_macro::bridge::scoped_cell::ScopedCell<T>::set::{{closure}}
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/scoped_cell.rs:80
  12: proc_macro::bridge::scoped_cell::ScopedCell<T>::replace
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/scoped_cell.rs:75
  13: proc_macro::bridge::scoped_cell::ScopedCell<T>::set
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/scoped_cell.rs:80
  14: proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::enter::{{closure}}
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:325
  15: std::thread::local::LocalKey<T>::try_with
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/local.rs:272
  16: std::thread::local::LocalKey<T>::with
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/thread/local.rs:248
  17: proc_macro::bridge::client::<impl proc_macro::bridge::Bridge>::enter
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:325
  18: proc_macro::bridge::client::run_client::{{closure}}
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:370
  19: <std::panic::AssertUnwindSafe<F> as core::ops::function::FnOnce<()>>::call_once
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:308
  20: std::panicking::try::do_call
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:381
  21: __rust_try
  22: std::panicking::try
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panicking.rs:345
  23: std::panic::catch_unwind
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/panic.rs:382
  24: proc_macro::bridge::client::run_client
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:369
  25: proc_macro::bridge::client::Client<fn(proc_macro::TokenStream) .> proc_macro::TokenStream>::expand1::run
             at /home/jonas/.rustup/toolchains/stable-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/proc_macro/src/bridge/client.rs:410
  26: proc_macro_srv::proc_macro::bridge::server::run_server
  27: proc_macro_srv::dylib::Expander::expand
  28: proc_macro_srv::ProcMacroSrv::expand
  29: proc_macro_srv::cli::run
  30: rust_analyzer::main
```

Co-authored-by: Jonas Schievink <[email protected]>

2 files changed, 17 insertions, 4 deletions

diff --git a/crates/base_db/src/input.rs b/crates/base_db/src/input.rs
index cda5e57dc..9567bcc42 100644
--- a/crates/base_db/src/input.rs
+++ b/crates/base_db/src/input.rs
@@ -6,12 +6,12 @@
 //! actual IO. See `vfs` and `project_model` in the `rust-analyzer` crate for how
 //! actual IO is done and lowered to input.
 
-use std::{fmt, iter::FromIterator, ops, str::FromStr, sync::Arc};
+use std::{fmt, iter::FromIterator, ops, panic::RefUnwindSafe, str::FromStr, sync::Arc};
 
 use cfg::CfgOptions;
 use rustc_hash::{FxHashMap, FxHashSet};
 use syntax::SmolStr;
-use tt::TokenExpander;
+use tt::{ExpansionError, Subtree};
 use vfs::{file_set::FileSet, FileId, VfsPath};
 
 /// Files are grouped into source roots. A source root is a directory on the
@@ -150,11 +150,20 @@ pub enum ProcMacroKind {
     Attr,
 }
 
+pub trait ProcMacroExpander: fmt::Debug + Send + Sync + RefUnwindSafe {
+    fn expand(
+        &self,
+        subtree: &Subtree,
+        attrs: Option<&Subtree>,
+        env: &Env,
+    ) -> Result<Subtree, ExpansionError>;
+}
+
 #[derive(Debug, Clone)]
 pub struct ProcMacro {
     pub name: SmolStr,
     pub kind: ProcMacroKind,
-    pub expander: Arc<dyn TokenExpander>,
+    pub expander: Arc<dyn ProcMacroExpander>,
 }
 
 impl Eq for ProcMacro {}
@@ -413,6 +422,10 @@ impl Env {
     pub fn get(&self, env: &str) -> Option<String> {
         self.entries.get(env).cloned()
     }
+
+    pub fn iter(&self) -> impl Iterator<Item = (&str, &str)> {
+        self.entries.iter().map(|(k, v)| (k.as_str(), v.as_str()))
+    }
 }
 
 #[derive(Debug)]
diff --git a/crates/base_db/src/lib.rs b/crates/base_db/src/lib.rs
index 595f28ada..5f77a0b1f 100644
--- a/crates/base_db/src/lib.rs
+++ b/crates/base_db/src/lib.rs
@@ -14,7 +14,7 @@ pub use crate::{
     change::Change,
     input::{
         CrateData, CrateDisplayName, CrateGraph, CrateId, CrateName, Dependency, Edition, Env,
-        ProcMacro, ProcMacroId, ProcMacroKind, SourceRoot, SourceRootId,
+        ProcMacro, ProcMacroExpander, ProcMacroId, ProcMacroKind, SourceRoot, SourceRootId,
     },
 };
 pub use salsa;