Merge #2201

2201: Resolve core types r=matklad a=Matthias247

This adds support for completion and goto definition of
types defined within the "core" crate. The core crate is
added as a dependency to each crate in the project.

The core crate exported it's own prelude. This caused
now all crates to inherit the core crates prelude instead
of the std crates. In order to avoid the problem the
prelude resolution has been changed to overwrite
an already resolved prelude if this was set to a crate
named core - in order to pick a better prelude like std.

Fixes #2199

Co-authored-by: Matthias Einwag <[email protected]>

2 files changed, 13 insertions, 1 deletions

diff --git a/crates/ra_project_model/src/lib.rs b/crates/ra_project_model/src/lib.rs
index 8b8663a78..0e14f1b70 100644
--- a/crates/ra_project_model/src/lib.rs
+++ b/crates/ra_project_model/src/lib.rs
@@ -199,6 +199,7 @@ impl ProjectWorkspace {
                     }
                 }
 
+                let libcore = sysroot.core().and_then(|it| sysroot_crates.get(&it).copied());
                 let libstd = sysroot.std().and_then(|it| sysroot_crates.get(&it).copied());
 
                 let mut pkg_to_lib_crate = FxHashMap::default();
@@ -226,7 +227,7 @@ impl ProjectWorkspace {
                         }
                     }
 
-                    // Set deps to the std and to the lib target of the current package
+                    // Set deps to the core, std and to the lib target of the current package
                     for &from in pkg_crates.get(&pkg).into_iter().flatten() {
                         if let Some(to) = lib_tgt {
                             if to != from {
@@ -240,6 +241,13 @@ impl ProjectWorkspace {
                                 }
                             }
                         }
+                        // core is added as a dependency before std in order to
+                        // mimic rustcs dependency order
+                        if let Some(core) = libcore {
+                            if let Err(_) = crate_graph.add_dep(from, "core".into(), core) {
+                                log::error!("cyclic dependency on core for {}", pkg.name(&cargo))
+                            }
+                        }
                         if let Some(std) = libstd {
                             if let Err(_) = crate_graph.add_dep(from, "std".into(), std) {
                                 log::error!("cyclic dependency on std for {}", pkg.name(&cargo))
diff --git a/crates/ra_project_model/src/sysroot.rs b/crates/ra_project_model/src/sysroot.rs
index 35d6df5cb..3d827809e 100644
--- a/crates/ra_project_model/src/sysroot.rs
+++ b/crates/ra_project_model/src/sysroot.rs
@@ -27,6 +27,10 @@ struct SysrootCrateData {
 }
 
 impl Sysroot {
+    pub fn core(&self) -> Option<SysrootCrate> {
+        self.by_name("core")
+    }
+
     pub fn std(&self) -> Option<SysrootCrate> {
         self.by_name("std")
     }