5 files changed, 15 insertions, 106 deletions

diff --git a/crates/base_db/Cargo.toml b/crates/base_db/Cargo.toml
index 1724d2f85..69173ad1f 100644
--- a/crates/base_db/Cargo.toml
+++ b/crates/base_db/Cargo.toml
@@ -10,7 +10,7 @@ edition = "2018"
 doctest = false
 
 [dependencies]
-salsa = "0.16.0"
+salsa = "0.17.0-pre.1"
 rustc-hash = "1.1.0"
 
 syntax = { path = "../syntax", version = "0.0.0" }
diff --git a/crates/base_db/src/cancellation.rs b/crates/base_db/src/cancellation.rs
deleted file mode 100644
index 7420a1976..000000000
--- a/crates/base_db/src/cancellation.rs
+++ /dev/null
@@ -1,48 +0,0 @@
-//! Utility types to support cancellation.
-//!
-//! In a typical IDE use-case, requests and modification happen concurrently, as
-//! in the following scenario:
-//!
-//!   * user types a character,
-//!   * a syntax highlighting process is started
-//!   * user types next character, while syntax highlighting *is still in
-//!     progress*.
-//!
-//! In this situation, we want to react to modification as quickly as possible.
-//! At the same time, in-progress results are not very interesting, because they
-//! are invalidated by the edit anyway. So, we first cancel all in-flight
-//! requests, and then apply modification knowing that it won't interfere with
-//! any background processing (this bit is handled by salsa, see the
-//! `BaseDatabase::check_canceled` method).
-
-/// An "error" signifying that the operation was canceled.
-#[derive(Clone, PartialEq, Eq, Hash)]
-pub struct Canceled {
-    _private: (),
-}
-
-impl Canceled {
-    pub(crate) fn new() -> Canceled {
-        Canceled { _private: () }
-    }
-
-    pub fn throw() -> ! {
-        // We use resume and not panic here to avoid running the panic
-        // hook (that is, to avoid collecting and printing backtrace).
-        std::panic::resume_unwind(Box::new(Canceled::new()))
-    }
-}
-
-impl std::fmt::Display for Canceled {
-    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        fmt.write_str("canceled")
-    }
-}
-
-impl std::fmt::Debug for Canceled {
-    fn fmt(&self, fmt: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(fmt, "Canceled")
-    }
-}
-
-impl std::error::Error for Canceled {}
diff --git a/crates/base_db/src/fixture.rs b/crates/base_db/src/fixture.rs
index 0132565e4..69ceba735 100644
--- a/crates/base_db/src/fixture.rs
+++ b/crates/base_db/src/fixture.rs
@@ -34,19 +34,13 @@ pub trait WithFixture: Default + SourceDatabaseExt + 'static {
 
     fn with_position(ra_fixture: &str) -> (Self, FilePosition) {
         let (db, file_id, range_or_offset) = Self::with_range_or_offset(ra_fixture);
-        let offset = match range_or_offset {
-            RangeOrOffset::Range(_) => panic!("Expected a cursor position, got a range instead"),
-            RangeOrOffset::Offset(it) => it,
-        };
+        let offset = range_or_offset.expect_offset();
         (db, FilePosition { file_id, offset })
     }
 
     fn with_range(ra_fixture: &str) -> (Self, FileRange) {
         let (db, file_id, range_or_offset) = Self::with_range_or_offset(ra_fixture);
-        let range = match range_or_offset {
-            RangeOrOffset::Range(it) => it,
-            RangeOrOffset::Offset(_) => panic!("Expected a cursor range, got a position instead"),
-        };
+        let range = range_or_offset.expect_range();
         (db, FileRange { file_id, range })
     }
 
diff --git a/crates/base_db/src/input.rs b/crates/base_db/src/input.rs
index 0ef77ef5d..23cb0c839 100644
--- a/crates/base_db/src/input.rs
+++ b/crates/base_db/src/input.rs
@@ -53,11 +53,15 @@ impl SourceRoot {
 }
 
 /// `CrateGraph` is a bit of information which turns a set of text files into a
-/// number of Rust crates. Each crate is defined by the `FileId` of its root module,
-/// the set of cfg flags (not yet implemented) and the set of dependencies. Note
-/// that, due to cfg's, there might be several crates for a single `FileId`! As
-/// in the rust-lang proper, a crate does not have a name. Instead, names are
-/// specified on dependency edges. That is, a crate might be known under
+/// number of Rust crates.
+///
+/// Each crate is defined by the `FileId` of its root module, the set of enabled
+/// `cfg` flags and the set of dependencies.
+///
+/// Note that, due to cfg's, there might be several crates for a single `FileId`!
+///
+/// For the purposes of analysis, a crate does not have a name. Instead, names
+/// are specified on dependency edges. That is, a crate might be known under
 /// different names in different dependent crates.
 ///
 /// Note that `CrateGraph` is build-system agnostic: it's a concept of the Rust
@@ -143,7 +147,7 @@ impl CrateDisplayName {
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash)]
 pub struct ProcMacroId(pub u32);
 
-#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+#[derive(Copy, Clone, Eq, PartialEq, Debug, Hash)]
 pub enum ProcMacroKind {
     CustomDerive,
     FuncLike,
diff --git a/crates/base_db/src/lib.rs b/crates/base_db/src/lib.rs
index 980a0ed98..62bf2a4b2 100644
--- a/crates/base_db/src/lib.rs
+++ b/crates/base_db/src/lib.rs
@@ -1,5 +1,4 @@
 //! base_db defines basic database traits. The concrete DB is defined by ide.
-mod cancellation;
 mod input;
 mod change;
 pub mod fixture;
@@ -10,14 +9,13 @@ use rustc_hash::FxHashSet;
 use syntax::{ast, Parse, SourceFile, TextRange, TextSize};
 
 pub use crate::{
-    cancellation::Canceled,
     change::Change,
     input::{
         CrateData, CrateDisplayName, CrateGraph, CrateId, CrateName, Dependency, Edition, Env,
         ProcMacro, ProcMacroExpander, ProcMacroId, ProcMacroKind, SourceRoot, SourceRootId,
     },
 };
-pub use salsa;
+pub use salsa::{self, Cancelled};
 pub use vfs::{file_set::FileSet, AnchoredPath, AnchoredPathBuf, FileId, VfsPath};
 
 #[macro_export]
@@ -38,45 +36,6 @@ pub trait Upcast<T: ?Sized> {
     fn upcast(&self) -> &T;
 }
 
-pub trait CheckCanceled {
-    /// Aborts current query if there are pending changes.
-    ///
-    /// rust-analyzer needs to be able to answer semantic questions about the
-    /// code while the code is being modified. A common problem is that a
-    /// long-running query is being calculated when a new change arrives.
-    ///
-    /// We can't just apply the change immediately: this will cause the pending
-    /// query to see inconsistent state (it will observe an absence of
-    /// repeatable read). So what we do is we **cancel** all pending queries
-    /// before applying the change.
-    ///
-    /// We implement cancellation by panicking with a special value and catching
-    /// it on the API boundary. Salsa explicitly supports this use-case.
-    fn check_canceled(&self);
-
-    fn catch_canceled<F, T>(&self, f: F) -> Result<T, Canceled>
-    where
-        Self: Sized + panic::RefUnwindSafe,
-        F: FnOnce(&Self) -> T + panic::UnwindSafe,
-    {
-        // Uncomment to debug missing cancellations.
-        // let _span = profile::heartbeat_span();
-        panic::catch_unwind(|| f(self)).map_err(|err| match err.downcast::<Canceled>() {
-            Ok(canceled) => *canceled,
-            Err(payload) => panic::resume_unwind(payload),
-        })
-    }
-}
-
-impl<T: salsa::Database> CheckCanceled for T {
-    fn check_canceled(&self) {
-        // profile::heartbeat();
-        if self.salsa_runtime().is_current_revision_canceled() {
-            Canceled::throw()
-        }
-    }
-}
-
 #[derive(Clone, Copy, Debug)]
 pub struct FilePosition {
     pub file_id: FileId,
@@ -101,7 +60,7 @@ pub trait FileLoader {
 /// Database which stores all significant input facts: source code and project
 /// model. Everything else in rust-analyzer is derived from these queries.
 #[salsa::query_group(SourceDatabaseStorage)]
-pub trait SourceDatabase: CheckCanceled + FileLoader + std::fmt::Debug {
+pub trait SourceDatabase: FileLoader + std::fmt::Debug {
     // Parses the file into the syntax tree.
     #[salsa::invoke(parse_query)]
     fn parse(&self, file_id: FileId) -> Parse<ast::SourceFile>;