Merge #1154

1154: Initial support for lang items (and str completion) r=flodiebold a=marcogroppo

This PR adds partial support for lang items.
For now, the only supported lang items are the ones that target an impl block.

Lang items are now resolved during type inference - this means that `str` completion now works.

Fixes #1139.

(thanks Florian Diebold for the help!)


Co-authored-by: Marco Groppo <[email protected]>

3 files changed, 16 insertions, 1 deletions

diff --git a/crates/ra_syntax/src/ast/extensions.rs b/crates/ra_syntax/src/ast/extensions.rs
index ca33b43e7..5c4c0ffc1 100644
--- a/crates/ra_syntax/src/ast/extensions.rs
+++ b/crates/ra_syntax/src/ast/extensions.rs
@@ -65,6 +65,20 @@ impl ast::Attr {
             None
         }
     }
+
+    pub fn as_key_value(&self) -> Option<(SmolStr, SmolStr)> {
+        let tt = self.value()?;
+        let tt_node = tt.syntax();
+        let attr = tt_node.children_with_tokens().nth(1)?;
+        if attr.kind() == IDENT {
+            let key = attr.as_token()?.text().clone();
+            let val_node = tt_node.children_with_tokens().find(|t| t.kind() == STRING)?;
+            let val = val_node.as_token()?.text().trim_start_matches("\"").trim_end_matches("\"");
+            Some((key, SmolStr::new(val)))
+        } else {
+            None
+        }
+    }
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
diff --git a/crates/ra_syntax/src/ast/generated.rs b/crates/ra_syntax/src/ast/generated.rs
index 17de4f058..fae371509 100644
--- a/crates/ra_syntax/src/ast/generated.rs
+++ b/crates/ra_syntax/src/ast/generated.rs
@@ -1325,6 +1325,7 @@ impl ToOwned for ImplBlock {
 
 
 impl ast::TypeParamsOwner for ImplBlock {}
+impl ast::AttrsOwner for ImplBlock {}
 impl ImplBlock {
     pub fn item_list(&self) -> Option<&ItemList> {
         super::child_opt(self)
diff --git a/crates/ra_syntax/src/grammar.ron b/crates/ra_syntax/src/grammar.ron
index 663e3a2f9..5bdcf9c84 100644
--- a/crates/ra_syntax/src/grammar.ron
+++ b/crates/ra_syntax/src/grammar.ron
@@ -345,7 +345,7 @@ Grammar(
             ],
             options: ["TypeRef"]
         ),
-        "ImplBlock": (options: ["ItemList"], traits: ["TypeParamsOwner"]),
+        "ImplBlock": (options: ["ItemList"], traits: ["TypeParamsOwner", "AttrsOwner"]),
 
         "ParenType": (options: ["TypeRef"]),
         "TupleType": ( collections: [["fields", "TypeRef"]] ),