14 files changed, 221 insertions, 24 deletions

diff --git a/Cargo.lock b/Cargo.lock
index bf2297e69..1e5f00de0 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -334,7 +334,6 @@ dependencies = [
  "languageserver-types 0.53.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -732,7 +731,6 @@ dependencies = [
  "relative-path 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-hash 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
- "serde_derive 1.0.82 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.33 (registry+https://github.com/rust-lang/crates.io-index)",
  "smol_str 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/crates/gen_lsp_server/Cargo.toml b/crates/gen_lsp_server/Cargo.toml
index 6c91e38aa..5f90d39d6 100644
--- a/crates/gen_lsp_server/Cargo.toml
+++ b/crates/gen_lsp_server/Cargo.toml
@@ -13,5 +13,4 @@ log = "0.4.3"
 failure = "0.1.2"
 serde_json = "1.0.24"
 serde = "1.0.71"
-serde_derive = "1.0.71"
 crossbeam-channel = "0.2.4"
diff --git a/crates/gen_lsp_server/src/msg.rs b/crates/gen_lsp_server/src/msg.rs
index 22d273d55..ef6358cb1 100644
--- a/crates/gen_lsp_server/src/msg.rs
+++ b/crates/gen_lsp_server/src/msg.rs
@@ -1,7 +1,7 @@
 use std::io::{BufRead, Write};
 
 use languageserver_types::{notification::Notification, request::Request};
-use serde_derive::{Deserialize, Serialize};
+use serde::{Deserialize, Serialize};
 use serde_json::{from_str, from_value, to_string, to_value, Value};
 use failure::{bail, format_err};
 
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index 1c8aa308b..b2f4cd228 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -72,13 +72,23 @@ struct RemoveFile {
 
 impl fmt::Debug for AnalysisChange {
     fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
-        fmt.debug_struct("AnalysisChange")
-            .field("new_roots", &self.new_roots)
-            .field("roots_changed", &self.roots_changed)
-            .field("files_changed", &self.files_changed.len())
-            .field("libraries_added", &self.libraries_added.len())
-            .field("crate_graph", &self.crate_graph)
-            .finish()
+        let mut d = fmt.debug_struct("AnalysisChange");
+        if !self.new_roots.is_empty() {
+            d.field("new_roots", &self.new_roots);
+        }
+        if !self.roots_changed.is_empty() {
+            d.field("roots_changed", &self.roots_changed);
+        }
+        if !self.files_changed.is_empty() {
+            d.field("files_changed", &self.files_changed.len());
+        }
+        if !self.libraries_added.is_empty() {
+            d.field("libraries_added", &self.libraries_added.len());
+        }
+        if !self.crate_graph.is_some() {
+            d.field("crate_graph", &self.crate_graph);
+        }
+        d.finish()
     }
 }
 
diff --git a/crates/ra_db/src/input.rs b/crates/ra_db/src/input.rs
index f12dd9345..ead8dfe48 100644
--- a/crates/ra_db/src/input.rs
+++ b/crates/ra_db/src/input.rs
@@ -98,6 +98,9 @@ impl CrateGraph {
     pub fn add_dep(&mut self, from: CrateId, name: SmolStr, to: CrateId) {
         self.arena.get_mut(&from).unwrap().add_dep(name, to)
     }
+    pub fn is_empty(&self) -> bool {
+        self.arena.is_empty()
+    }
     pub fn crate_root(&self, crate_id: CrateId) -> FileId {
         self.arena[&crate_id].file_id
     }
diff --git a/crates/ra_editor/src/typing.rs b/crates/ra_editor/src/typing.rs
index 46a6e2d62..5e412bcfa 100644
--- a/crates/ra_editor/src/typing.rs
+++ b/crates/ra_editor/src/typing.rs
@@ -164,6 +164,16 @@ fn remove_newline(
     if join_single_expr_block(edit, node).is_some() {
         return;
     }
+    // ditto for
+    //
+    // ```
+    // use foo::{<|>
+    //    bar
+    // };
+    // ```
+    if join_single_use_tree(edit, node).is_some() {
+        return;
+    }
 
     // The node is between two other nodes
     let prev = node.prev_sibling().unwrap();
@@ -228,6 +238,36 @@ fn single_expr(block: ast::Block) -> Option<ast::Expr> {
     res
 }
 
+fn join_single_use_tree(edit: &mut TextEditBuilder, node: SyntaxNodeRef) -> Option<()> {
+    let use_tree_list = ast::UseTreeList::cast(node.parent()?)?;
+    let tree = single_use_tree(use_tree_list)?;
+    edit.replace(
+        use_tree_list.syntax().range(),
+        tree.syntax().text().to_string(),
+    );
+    Some(())
+}
+
+fn single_use_tree(tree_list: ast::UseTreeList) -> Option<ast::UseTree> {
+    let mut res = None;
+    for child in tree_list.syntax().children() {
+        if let Some(tree) = ast::UseTree::cast(child) {
+            if tree.syntax().text().contains('\n') {
+                return None;
+            }
+            if mem::replace(&mut res, Some(tree)).is_some() {
+                return None;
+            }
+        } else {
+            match child.kind() {
+                WHITESPACE | L_CURLY | R_CURLY | COMMA => (),
+                _ => return None,
+            }
+        }
+    }
+    res
+}
+
 fn compute_ws(left: SyntaxNodeRef, right: SyntaxNodeRef) -> &'static str {
     match left.kind() {
         L_PAREN | L_BRACK => return "",
@@ -306,6 +346,24 @@ fn foo() {
     }
 
     #[test]
+    fn test_join_lines_use_tree() {
+        check_join_lines(
+            r"
+use ra_syntax::{
+    algo::<|>{
+        find_leaf_at_offset,
+    },
+    ast,
+};",
+            r"
+use ra_syntax::{
+    algo::<|>find_leaf_at_offset,
+    ast,
+};",
+        );
+    }
+
+    #[test]
     fn test_join_lines_normal_comments() {
         check_join_lines(
             r"
diff --git a/crates/ra_lsp_server/Cargo.toml b/crates/ra_lsp_server/Cargo.toml
index fc10096e5..3c8c240cd 100644
--- a/crates/ra_lsp_server/Cargo.toml
+++ b/crates/ra_lsp_server/Cargo.toml
@@ -12,7 +12,6 @@ failure = "0.1.2"
 failure_derive = "0.1.2"
 serde_json = "1.0.24"
 serde = "1.0.71"
-serde_derive = "1.0.71"
 drop_bomb = "0.1.0"
 crossbeam-channel = "0.2.4"
 flexi_logger = "0.10.0"
diff --git a/crates/ra_lsp_server/src/main.rs b/crates/ra_lsp_server/src/main.rs
index 4497980e5..eae601f91 100644
--- a/crates/ra_lsp_server/src/main.rs
+++ b/crates/ra_lsp_server/src/main.rs
@@ -1,7 +1,7 @@
-use serde_derive::Deserialize;
-use serde::Deserialize as _D;
+use serde::Deserialize;
 use flexi_logger::{Duplicate, Logger};
 use gen_lsp_server::{run_server, stdio_transport};
+
 use ra_lsp_server::Result;
 
 fn main() -> Result<()> {
diff --git a/crates/ra_lsp_server/src/req.rs b/crates/ra_lsp_server/src/req.rs
index 999792ecb..747ab8a8c 100644
--- a/crates/ra_lsp_server/src/req.rs
+++ b/crates/ra_lsp_server/src/req.rs
@@ -1,4 +1,4 @@
-use serde_derive::{Serialize, Deserialize};
+use serde::{Serialize, Deserialize};
 use languageserver_types::{Location, Position, Range, TextDocumentIdentifier, Url};
 use rustc_hash::FxHashMap;
 use url_serde;
diff --git a/crates/ra_syntax/src/grammar/type_params.rs b/crates/ra_syntax/src/grammar/type_params.rs
index 863f8e00c..7db25beba 100644
--- a/crates/ra_syntax/src/grammar/type_params.rs
+++ b/crates/ra_syntax/src/grammar/type_params.rs
@@ -96,6 +96,7 @@ pub(super) fn bounds_without_colon(p: &mut Parser) {
 //    'a: 'b + 'c,
 //    T: Clone + Copy + 'static,
 //    Iterator::Item: 'a,
+//    <T as Iterator>::Item: 'a
 // {}
 pub(super) fn opt_where_clause(p: &mut Parser) {
     if !p.at(WHERE_KW) {
@@ -104,7 +105,11 @@ pub(super) fn opt_where_clause(p: &mut Parser) {
     let m = p.start();
     p.bump();
     loop {
-        if !(paths::is_path_start(p) || p.current() == LIFETIME || p.current() == FOR_KW) {
+        if !(paths::is_path_start(p)
+            || p.current() == LIFETIME
+            || p.current() == FOR_KW
+            || p.current() == L_ANGLE)
+        {
             break;
         }
         where_predicate(p);
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.rs b/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.rs
index 592a005f9..19d7e571b 100644
--- a/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.rs
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.rs
@@ -3,4 +3,5 @@ where
    'a: 'b + 'c,
    T: Clone + Copy + 'static,
    Iterator::Item: 'a,
+   <T as Iterator>::Item: 'a
 {}
diff --git a/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.txt b/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.txt
index 54c3d64f1..68485dc0b 100644
--- a/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.txt
+++ b/crates/ra_syntax/tests/data/parser/inline/ok/0056_where_clause.txt
@@ -1,5 +1,5 @@
-SOURCE_FILE@[0; 87)
-  FN_DEF@[0; 86)
+SOURCE_FILE@[0; 116)
+  FN_DEF@[0; 115)
     FN_KW@[0; 2)
     WHITESPACE@[2; 3)
     NAME@[3; 6)
@@ -8,7 +8,7 @@ SOURCE_FILE@[0; 87)
       L_PAREN@[6; 7)
       R_PAREN@[7; 8)
     WHITESPACE@[8; 9)
-    WHERE_CLAUSE@[9; 83)
+    WHERE_CLAUSE@[9; 112)
       WHERE_KW@[9; 14)
       WHITESPACE@[14; 18)
       WHERE_PRED@[18; 29)
@@ -64,8 +64,36 @@ SOURCE_FILE@[0; 87)
         WHITESPACE@[79; 80)
         LIFETIME@[80; 82) "'a"
       COMMA@[82; 83)
-    WHITESPACE@[83; 84)
-    BLOCK@[84; 86)
-      L_CURLY@[84; 85)
-      R_CURLY@[85; 86)
-  WHITESPACE@[86; 87)
+      WHITESPACE@[83; 87)
+      WHERE_PRED@[87; 112)
+        PATH_TYPE@[87; 108)
+          PATH@[87; 108)
+            PATH@[87; 102)
+              PATH_SEGMENT@[87; 102)
+                L_ANGLE@[87; 88)
+                PATH_TYPE@[88; 89)
+                  PATH@[88; 89)
+                    PATH_SEGMENT@[88; 89)
+                      NAME_REF@[88; 89)
+                        IDENT@[88; 89) "T"
+                WHITESPACE@[89; 90)
+                AS_KW@[90; 92)
+                WHITESPACE@[92; 93)
+                PATH_TYPE@[93; 101)
+                  PATH@[93; 101)
+                    PATH_SEGMENT@[93; 101)
+                      NAME_REF@[93; 101)
+                        IDENT@[93; 101) "Iterator"
+                R_ANGLE@[101; 102)
+            COLONCOLON@[102; 104)
+            PATH_SEGMENT@[104; 108)
+              NAME_REF@[104; 108)
+                IDENT@[104; 108) "Item"
+        COLON@[108; 109)
+        WHITESPACE@[109; 110)
+        LIFETIME@[110; 112) "'a"
+    WHITESPACE@[112; 113)
+    BLOCK@[113; 115)
+      L_CURLY@[113; 114)
+      R_CURLY@[114; 115)
+  WHITESPACE@[115; 116)
diff --git a/crates/ra_syntax/tests/data/parser/ok/0036_fully_qualified.rs b/crates/ra_syntax/tests/data/parser/ok/0036_fully_qualified.rs
new file mode 100644
index 000000000..6da27933e
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/ok/0036_fully_qualified.rs
@@ -0,0 +1,8 @@
+// https://github.com/rust-analyzer/rust-analyzer/issues/311
+
+pub fn foo<S: Iterator>() -> String
+where
+    <S as Iterator>::Item: Eq,
+{
+    "".to_owned()
+}
diff --git a/crates/ra_syntax/tests/data/parser/ok/0036_fully_qualified.txt b/crates/ra_syntax/tests/data/parser/ok/0036_fully_qualified.txt
new file mode 100644
index 000000000..208e5e51c
--- /dev/null
+++ b/crates/ra_syntax/tests/data/parser/ok/0036_fully_qualified.txt
@@ -0,0 +1,88 @@
+SOURCE_FILE@[0; 157)
+  COMMENT@[0; 60)
+  WHITESPACE@[60; 62)
+  FN_DEF@[62; 156)
+    VISIBILITY@[62; 65)
+      PUB_KW@[62; 65)
+    WHITESPACE@[65; 66)
+    FN_KW@[66; 68)
+    WHITESPACE@[68; 69)
+    NAME@[69; 72)
+      IDENT@[69; 72) "foo"
+    TYPE_PARAM_LIST@[72; 85)
+      L_ANGLE@[72; 73)
+      TYPE_PARAM@[73; 84)
+        NAME@[73; 74)
+          IDENT@[73; 74) "S"
+        COLON@[74; 75)
+        WHITESPACE@[75; 76)
+        PATH_TYPE@[76; 84)
+          PATH@[76; 84)
+            PATH_SEGMENT@[76; 84)
+              NAME_REF@[76; 84)
+                IDENT@[76; 84) "Iterator"
+      R_ANGLE@[84; 85)
+    PARAM_LIST@[85; 87)
+      L_PAREN@[85; 86)
+      R_PAREN@[86; 87)
+    WHITESPACE@[87; 88)
+    RET_TYPE@[88; 97)
+      THIN_ARROW@[88; 90)
+      WHITESPACE@[90; 91)
+      PATH_TYPE@[91; 97)
+        PATH@[91; 97)
+          PATH_SEGMENT@[91; 97)
+            NAME_REF@[91; 97)
+              IDENT@[91; 97) "String"
+    WHITESPACE@[97; 98)
+    WHERE_CLAUSE@[98; 134)
+      WHERE_KW@[98; 103)
+      WHITESPACE@[103; 108)
+      WHERE_PRED@[108; 133)
+        PATH_TYPE@[108; 129)
+          PATH@[108; 129)
+            PATH@[108; 123)
+              PATH_SEGMENT@[108; 123)
+                L_ANGLE@[108; 109)
+                PATH_TYPE@[109; 110)
+                  PATH@[109; 110)
+                    PATH_SEGMENT@[109; 110)
+                      NAME_REF@[109; 110)
+                        IDENT@[109; 110) "S"
+                WHITESPACE@[110; 111)
+                AS_KW@[111; 113)
+                WHITESPACE@[113; 114)
+                PATH_TYPE@[114; 122)
+                  PATH@[114; 122)
+                    PATH_SEGMENT@[114; 122)
+                      NAME_REF@[114; 122)
+                        IDENT@[114; 122) "Iterator"
+                R_ANGLE@[122; 123)
+            COLONCOLON@[123; 125)
+            PATH_SEGMENT@[125; 129)
+              NAME_REF@[125; 129)
+                IDENT@[125; 129) "Item"
+        COLON@[129; 130)
+        WHITESPACE@[130; 131)
+        PATH_TYPE@[131; 133)
+          PATH@[131; 133)
+            PATH_SEGMENT@[131; 133)
+              NAME_REF@[131; 133)
+                IDENT@[131; 133) "Eq"
+      COMMA@[133; 134)
+    WHITESPACE@[134; 135)
+    BLOCK@[135; 156)
+      L_CURLY@[135; 136)
+      WHITESPACE@[136; 141)
+      METHOD_CALL_EXPR@[141; 154)
+        LITERAL@[141; 143)
+          STRING@[141; 143)
+        DOT@[143; 144)
+        NAME_REF@[144; 152)
+          IDENT@[144; 152) "to_owned"
+        ARG_LIST@[152; 154)
+          L_PAREN@[152; 153)
+          R_PAREN@[153; 154)
+      WHITESPACE@[154; 155)
+      R_CURLY@[155; 156)
+  WHITESPACE@[156; 157)