15 files changed, 181 insertions, 86 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 10bd94f7b..67822cb8a 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -45,7 +45,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "backtrace"
-version = "0.3.41"
+version = "0.3.42"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "backtrace-sys 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -463,10 +463,10 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "1.3.0"
+version = "1.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "autocfg 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -730,7 +730,7 @@ dependencies = [
 
 [[package]]
 name = "num_cpus"
-version = "1.11.1"
+version = "1.12.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "hermit-abi 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1038,7 +1038,7 @@ dependencies = [
  "either 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "format-buf 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "fst 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)",
- "indexmap 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "indexmap 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "insta 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "join_to_string 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1114,7 +1114,7 @@ dependencies = [
 name = "ra_prof"
 version = "0.1.0"
 dependencies = [
- "backtrace 0.3.41 (registry+https://github.com/rust-lang/crates.io-index)",
+ "backtrace 0.3.42 (registry+https://github.com/rust-lang/crates.io-index)",
  "itertools 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "jemalloc-ctl 0.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "jemallocator 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1353,7 +1353,7 @@ dependencies = [
  "crossbeam-queue 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1449,7 +1449,7 @@ version = "0.14.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "indexmap 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "indexmap 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.4.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "parking_lot 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1631,7 +1631,7 @@ name = "threadpool"
 version = "1.7.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num_cpus 1.12.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -1781,7 +1781,7 @@ dependencies = [
 "checksum atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)" = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 "checksum autocfg 0.1.7 (registry+https://github.com/rust-lang/crates.io-index)" = "1d49d90015b3c36167a20fe2810c5cd875ad504b39cff3d4eae7977e6b7c1cb2"
 "checksum autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
-"checksum backtrace 0.3.41 (registry+https://github.com/rust-lang/crates.io-index)" = "a4ed64ae6d9ebfd9893193c4b2532b1292ec97bd8271c9d7d0fa90cd78a34cba"
+"checksum backtrace 0.3.42 (registry+https://github.com/rust-lang/crates.io-index)" = "b4b1549d804b6c73f4817df2ba073709e96e426f12987127c48e6745568c350b"
 "checksum backtrace-sys 0.1.32 (registry+https://github.com/rust-lang/crates.io-index)" = "5d6575f128516de27e3ce99689419835fce9643a9b215a14d2b5b685be018491"
 "checksum base64 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b41b7ea54a0c9d92199de89e20e58d49f02f8e699814ef3fdf266f6f748d15c7"
 "checksum bit-set 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "e84c238982c4b1e1ee668d136c510c67a13465279c0cb367ea6baf6310620a80"
@@ -1832,7 +1832,7 @@ dependencies = [
 "checksum hermit-abi 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "eff2656d88f158ce120947499e971d743c05dbcbed62e5bd2f38f1698bbc3772"
 "checksum humantime 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "df004cfca50ef23c36850aaaa59ad52cc70d0e90243c3c7737a4dd32dc7a3c4f"
 "checksum idna 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "02e2673c30ee86b5b96a9cb52ad15718aa1f966f5ab9ad54a8b95d5ca33120a9"
-"checksum indexmap 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712d7b3ea5827fcb9d4fda14bf4da5f136f0db2ae9c8f4bd4e2d1c6fde4e6db2"
+"checksum indexmap 1.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "0b54058f0a6ff80b6803da8faf8997cde53872b38f4023728f6830b06cd3c0dc"
 "checksum inotify 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "24e40d6fd5d64e2082e0c796495c8ef5ad667a96d03e5aaa0becfd9d47bcbfb8"
 "checksum inotify-sys 0.1.3 (registry+https://github.com/rust-lang/crates.io-index)" = "e74a1aa87c59aeff6ef2cc2fa62d41bc43f54952f55652656b18a02fd5e356c0"
 "checksum insta 0.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "0d499dc062e841590a67230d853bce62d0abeb91304927871670b7c55c461349"
@@ -1863,7 +1863,7 @@ dependencies = [
 "checksum net2 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)" = "42550d9fb7b6684a6d404d9fa7250c2eb2646df731d1c06afc06dcee9e1bcf88"
 "checksum notify 4.0.15 (registry+https://github.com/rust-lang/crates.io-index)" = "80ae4a7688d1fab81c5bf19c64fc8db920be8d519ce6336ed4e7efe024724dbd"
 "checksum num-traits 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)" = "c62be47e61d1842b9170f0fdeec8eba98e60e90e5446449a0545e5152acd7096"
-"checksum num_cpus 1.11.1 (registry+https://github.com/rust-lang/crates.io-index)" = "76dac5ed2a876980778b8b85f75a71b6cbf0db0b1232ee12f826bccb00d09d72"
+"checksum num_cpus 1.12.0 (registry+https://github.com/rust-lang/crates.io-index)" = "46203554f085ff89c235cd12f7075f3233af9b11ed7c9e16dfe2560d03313ce6"
 "checksum once_cell 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "f5941ec2d5ee5916c709580d71553b81a633df245bcc73c04dcbd62152ceefc4"
 "checksum ordermap 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "a86ed3f5f244b372d6b1a00b72ef7f8876d0bc6a78a4c9985c53614041512063"
 "checksum parking_lot 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "92e98c49ab0b7ce5b222f2cc9193fc4efe11c6d0bd4f648e374684a6857b1cfc"
diff --git a/crates/ra_hir_ty/src/infer/expr.rs b/crates/ra_hir_ty/src/infer/expr.rs
index d6a17e469..31259a01d 100644
--- a/crates/ra_hir_ty/src/infer/expr.rs
+++ b/crates/ra_hir_ty/src/infer/expr.rs
@@ -386,11 +386,11 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
                     let lhs_ty = self.infer_expr(*lhs, &lhs_expectation);
                     // FIXME: find implementation of trait corresponding to operation
                     // symbol and resolve associated `Output` type
-                    let rhs_expectation = op::binary_op_rhs_expectation(*op, lhs_ty);
+                    let rhs_expectation = op::binary_op_rhs_expectation(*op, lhs_ty.clone());
                     let rhs_ty = self.infer_expr(*rhs, &Expectation::has_type(rhs_expectation));
 
                     // FIXME: similar as above, return ty is often associated trait type
-                    op::binary_op_return_ty(*op, rhs_ty)
+                    op::binary_op_return_ty(*op, lhs_ty, rhs_ty)
                 }
                 _ => Ty::Unknown,
             },
diff --git a/crates/ra_hir_ty/src/op.rs b/crates/ra_hir_ty/src/op.rs
index 09c47a76d..ae253ca04 100644
--- a/crates/ra_hir_ty/src/op.rs
+++ b/crates/ra_hir_ty/src/op.rs
@@ -1,13 +1,21 @@
-//! FIXME: write short doc here
-use hir_def::expr::{BinaryOp, CmpOp};
+//! Helper functions for binary operator type inference.
+use hir_def::expr::{ArithOp, BinaryOp, CmpOp};
 
 use super::{InferTy, Ty, TypeCtor};
 use crate::ApplicationTy;
 
-pub(super) fn binary_op_return_ty(op: BinaryOp, rhs_ty: Ty) -> Ty {
+pub(super) fn binary_op_return_ty(op: BinaryOp, lhs_ty: Ty, rhs_ty: Ty) -> Ty {
     match op {
         BinaryOp::LogicOp(_) | BinaryOp::CmpOp(_) => Ty::simple(TypeCtor::Bool),
         BinaryOp::Assignment { .. } => Ty::unit(),
+        BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => match lhs_ty {
+            Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
+                TypeCtor::Int(..) | TypeCtor::Float(..) => lhs_ty,
+                _ => Ty::Unknown,
+            },
+            Ty::Infer(InferTy::IntVar(..)) | Ty::Infer(InferTy::FloatVar(..)) => lhs_ty,
+            _ => Ty::Unknown,
+        },
         BinaryOp::ArithOp(_) => match rhs_ty {
             Ty::Apply(ApplicationTy { ctor, .. }) => match ctor {
                 TypeCtor::Int(..) | TypeCtor::Float(..) => rhs_ty,
@@ -36,6 +44,7 @@ pub(super) fn binary_op_rhs_expectation(op: BinaryOp, lhs_ty: Ty) -> Ty {
                 _ => Ty::Unknown,
             }
         }
+        BinaryOp::ArithOp(ArithOp::Shl) | BinaryOp::ArithOp(ArithOp::Shr) => Ty::Unknown,
         BinaryOp::CmpOp(CmpOp::Ord { .. })
         | BinaryOp::Assignment { op: Some(_) }
         | BinaryOp::ArithOp(_) => match lhs_ty {
diff --git a/crates/ra_hir_ty/src/tests/simple.rs b/crates/ra_hir_ty/src/tests/simple.rs
index f7e042c12..b7204ec00 100644
--- a/crates/ra_hir_ty/src/tests/simple.rs
+++ b/crates/ra_hir_ty/src/tests/simple.rs
@@ -614,6 +614,27 @@ fn test() -> bool {
 }
 
 #[test]
+fn infer_shift_op() {
+    assert_snapshot!(
+        infer(r#"
+fn test() {
+    1u32 << 5u8;
+    1u32 >> 5u8;
+}
+"#),
+        @r###"
+    [11; 48) '{     ...5u8; }': ()
+    [17; 21) '1u32': u32
+    [17; 28) '1u32 << 5u8': u32
+    [25; 28) '5u8': u8
+    [34; 38) '1u32': u32
+    [34; 45) '1u32 >> 5u8': u32
+    [42; 45) '5u8': u8
+    "###
+    );
+}
+
+#[test]
 fn infer_field_autoderef() {
     assert_snapshot!(
         infer(r#"
diff --git a/crates/ra_ide/src/display/function_signature.rs b/crates/ra_ide/src/display/function_signature.rs
index ddc53a52b..1e4a472b4 100644
--- a/crates/ra_ide/src/display/function_signature.rs
+++ b/crates/ra_ide/src/display/function_signature.rs
@@ -169,9 +169,22 @@ impl From<&'_ ast::FnDef> for FunctionSignature {
                     res.push(self_param.syntax().text().to_string())
                 }
 
-                res.extend(param_list.params().map(|param| {
-                    param.pat().map(|pat| pat.syntax().text().to_string()).unwrap_or_default()
-                }));
+                res.extend(
+                    param_list
+                        .params()
+                        .map(|param| {
+                            Some(
+                                param
+                                    .pat()?
+                                    .syntax()
+                                    .descendants()
+                                    .find_map(ast::Name::cast)?
+                                    .text()
+                                    .to_string(),
+                            )
+                        })
+                        .map(|param| param.unwrap_or_default()),
+                );
             }
             res
         }
diff --git a/crates/ra_ide/src/inlay_hints.rs b/crates/ra_ide/src/inlay_hints.rs
index 1b631c7cd..236557541 100644
--- a/crates/ra_ide/src/inlay_hints.rs
+++ b/crates/ra_ide/src/inlay_hints.rs
@@ -116,7 +116,7 @@ fn get_param_name_hints(
     let hints = parameters
         .zip(args)
         .filter_map(|(param, arg)| {
-            if arg.syntax().kind() == SyntaxKind::LITERAL {
+            if arg.syntax().kind() == SyntaxKind::LITERAL && !param.is_empty() {
                 Some((arg.syntax().text_range(), param))
             } else {
                 None
@@ -683,12 +683,12 @@ fn main() {
 struct Test {}
 
 impl Test {
-    fn method(&self, param: i32) -> i32 {
+    fn method(&self, mut param: i32) -> i32 {
         param * 2
     }
 }
 
-fn test_func(foo: i32, bar: i32, msg: &str, _: i32, last: i32) -> i32 {
+fn test_func(mut foo: i32, bar: i32, msg: &str, _: i32, last: i32) -> i32 {
     foo + bar
 }
 
@@ -704,37 +704,32 @@ fn main() {
         assert_debug_snapshot!(analysis.inlay_hints(file_id, None).unwrap(), @r###"
         [
             InlayHint {
-                range: [207; 218),
+                range: [215; 226),
                 kind: TypeHint,
                 label: "i32",
             },
             InlayHint {
-                range: [251; 252),
+                range: [259; 260),
                 kind: ParameterHint,
                 label: "foo",
             },
             InlayHint {
-                range: [254; 255),
+                range: [262; 263),
                 kind: ParameterHint,
                 label: "bar",
             },
             InlayHint {
-                range: [257; 264),
+                range: [265; 272),
                 kind: ParameterHint,
                 label: "msg",
             },
             InlayHint {
-                range: [266; 267),
-                kind: ParameterHint,
-                label: "_",
-            },
-            InlayHint {
-                range: [323; 326),
+                range: [331; 334),
                 kind: ParameterHint,
                 label: "param",
             },
             InlayHint {
-                range: [350; 354),
+                range: [358; 362),
                 kind: ParameterHint,
                 label: "param",
             },
diff --git a/crates/ra_parser/src/grammar.rs b/crates/ra_parser/src/grammar.rs
index 22f64a9f4..a46e11e1d 100644
--- a/crates/ra_parser/src/grammar.rs
+++ b/crates/ra_parser/src/grammar.rs
@@ -1,7 +1,7 @@
 //! This is the actual "grammar" of the Rust language.
 //!
 //! Each function in this module and its children corresponds
-//! to a production of the format grammar. Submodules roughly
+//! to a production of the formal grammar. Submodules roughly
 //! correspond to different *areas* of the grammar. By convention,
 //! each submodule starts with `use super::*` import and exports
 //! "public" productions via `pub(super)`.
diff --git a/crates/ra_parser/src/grammar/expressions.rs b/crates/ra_parser/src/grammar/expressions.rs
index d733499d1..06c92645e 100644
--- a/crates/ra_parser/src/grammar/expressions.rs
+++ b/crates/ra_parser/src/grammar/expressions.rs
@@ -19,6 +19,26 @@ pub(super) fn expr(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
     expr_bp(p, r, 1)
 }
 
+pub(super) fn expr_with_attrs(p: &mut Parser) -> bool {
+    let m = p.start();
+    let has_attrs = p.at(T![#]);
+    attributes::outer_attributes(p);
+
+    let (cm, _block_like) = expr(p);
+    let success = cm.is_some();
+
+    match (has_attrs, cm) {
+        (true, Some(cm)) => {
+            let kind = cm.kind();
+            cm.undo_completion(p).abandon(p);
+            m.complete(p, kind);
+        }
+        _ => m.abandon(p),
+    }
+
+    success
+}
+
 pub(super) fn expr_stmt(p: &mut Parser) -> (Option<CompletedMarker>, BlockLike) {
     let r = Restrictions { forbid_structs: false, prefer_stmt: true };
     expr_bp(p, r, 1)
@@ -540,11 +560,13 @@ fn arg_list(p: &mut Parser) {
     let m = p.start();
     p.bump(T!['(']);
     while !p.at(T![')']) && !p.at(EOF) {
-        if !p.at_ts(EXPR_FIRST) {
-            p.error("expected expression");
+        // test arg_with_attr
+        // fn main() {
+        //     foo(#[attr] 92)
+        // }
+        if !expr_with_attrs(p) {
             break;
         }
-        expr(p);
         if !p.at(T![')']) && !p.expect(T![,]) {
             break;
         }
diff --git a/crates/ra_parser/src/grammar/expressions/atom.rs b/crates/ra_parser/src/grammar/expressions/atom.rs
index a98a2a3ef..2cc321473 100644
--- a/crates/ra_parser/src/grammar/expressions/atom.rs
+++ b/crates/ra_parser/src/grammar/expressions/atom.rs
@@ -191,19 +191,8 @@ fn array_expr(p: &mut Parser) -> CompletedMarker {
 
         // test array_attrs
         // const A: &[i64] = &[1, #[cfg(test)] 2];
-        let m = p.start();
-        let has_attrs = p.at(T![#]);
-        attributes::outer_attributes(p);
-
-        let cm = expr(p).0;
-
-        match (has_attrs, cm) {
-            (true, Some(cm)) => {
-                let kind = cm.kind();
-                cm.undo_completion(p).abandon(p);
-                m.complete(p, kind);
-            }
-            _ => m.abandon(p),
+        if !expr_with_attrs(p) {
+            break;
         }
 
         if n_exprs == 1 && p.eat(T![;]) {
diff --git a/crates/ra_syntax/test_data/parser/err/0022_bad_exprs.txt b/crates/ra_syntax/test_data/parser/err/0022_bad_exprs.txt
index 310a82464..cb45eb2fc 100644
--- a/crates/ra_syntax/test_data/parser/err/0022_bad_exprs.txt
+++ b/crates/ra_syntax/test_data/parser/err/0022_bad_exprs.txt
@@ -12,8 +12,8 @@ SOURCE_FILE@[0; 112)
       BLOCK@[7; 33)
         L_CURLY@[7; 8) "{"
         WHITESPACE@[8; 9) " "
-        EXPR_STMT@[9; 26)
-          ARRAY_EXPR@[9; 26)
+        EXPR_STMT@[9; 17)
+          ARRAY_EXPR@[9; 17)
             L_BRACK@[9; 10) "["
             LITERAL@[10; 11)
               INT_NUMBER@[10; 11) "1"
@@ -25,10 +25,13 @@ SOURCE_FILE@[0; 112)
             WHITESPACE@[15; 16) " "
             ERROR@[16; 17)
               AT@[16; 17) "@"
+        EXPR_STMT@[17; 18)
+          ERROR@[17; 18)
             COMMA@[17; 18) ","
-            WHITESPACE@[18; 19) " "
-            ERROR@[19; 25)
-              STRUCT_KW@[19; 25) "struct"
+        WHITESPACE@[18; 19) " "
+        STRUCT_DEF@[19; 26)
+          STRUCT_KW@[19; 25) "struct"
+          ERROR@[25; 26)
             COMMA@[25; 26) ","
         WHITESPACE@[26; 27) " "
         LET_STMT@[27; 31)
@@ -51,14 +54,14 @@ SOURCE_FILE@[0; 112)
       BLOCK@[41; 68)
         L_CURLY@[41; 42) "{"
         WHITESPACE@[42; 43) " "
-        EXPR_STMT@[43; 52)
-          CALL_EXPR@[43; 52)
+        EXPR_STMT@[43; 54)
+          CALL_EXPR@[43; 54)
             PATH_EXPR@[43; 46)
               PATH@[43; 46)
                 PATH_SEGMENT@[43; 46)
                   NAME_REF@[43; 46)
                     IDENT@[43; 46) "foo"
-            ARG_LIST@[46; 52)
+            ARG_LIST@[46; 54)
               L_PAREN@[46; 47) "("
               LITERAL@[47; 48)
                 INT_NUMBER@[47; 48) "1"
@@ -67,10 +70,9 @@ SOURCE_FILE@[0; 112)
               LITERAL@[50; 51)
                 INT_NUMBER@[50; 51) "2"
               COMMA@[51; 52) ","
-        WHITESPACE@[52; 53) " "
-        EXPR_STMT@[53; 54)
-          ERROR@[53; 54)
-            AT@[53; 54) "@"
+              WHITESPACE@[52; 53) " "
+              ERROR@[53; 54)
+                AT@[53; 54) "@"
         EXPR_STMT@[54; 55)
           ERROR@[54; 55)
             COMMA@[54; 55) ","
@@ -101,8 +103,8 @@ SOURCE_FILE@[0; 112)
       BLOCK@[76; 111)
         L_CURLY@[76; 77) "{"
         WHITESPACE@[77; 78) " "
-        EXPR_STMT@[78; 91)
-          METHOD_CALL_EXPR@[78; 91)
+        EXPR_STMT@[78; 93)
+          METHOD_CALL_EXPR@[78; 93)
             PATH_EXPR@[78; 81)
               PATH@[78; 81)
                 PATH_SEGMENT@[78; 81)
@@ -111,7 +113,7 @@ SOURCE_FILE@[0; 112)
             DOT@[81; 82) "."
             NAME_REF@[82; 85)
               IDENT@[82; 85) "bar"
-            ARG_LIST@[85; 91)
+            ARG_LIST@[85; 93)
               L_PAREN@[85; 86) "("
               LITERAL@[86; 87)
                 INT_NUMBER@[86; 87) "1"
@@ -120,10 +122,9 @@ SOURCE_FILE@[0; 112)
               LITERAL@[89; 90)
                 INT_NUMBER@[89; 90) "2"
               COMMA@[90; 91) ","
-        WHITESPACE@[91; 92) " "
-        EXPR_STMT@[92; 93)
-          ERROR@[92; 93)
-            AT@[92; 93) "@"
+              WHITESPACE@[91; 92) " "
+              ERROR@[92; 93)
+                AT@[92; 93) "@"
         EXPR_STMT@[93; 94)
           ERROR@[93; 94)
             COMMA@[93; 94) ","
@@ -148,15 +149,14 @@ SOURCE_FILE@[0; 112)
         R_CURLY@[110; 111) "}"
   WHITESPACE@[111; 112) "\n"
 error 16: expected expression
-error 19: expected expression
-error 26: expected expression
-error 26: expected COMMA
-error 26: expected R_BRACK
-error 26: expected SEMI
+error 17: expected R_BRACK
+error 17: expected SEMI
+error 17: expected expression
+error 18: expected SEMI
+error 25: expected a name
+error 26: expected `;`, `{`, or `(`
 error 30: expected pattern
 error 31: expected SEMI
-error 52: expected expression
-error 52: expected SEMI
 error 53: expected expression
 error 54: expected SEMI
 error 54: expected expression
@@ -168,8 +168,6 @@ error 61: expected SEMI
 error 65: expected pattern
 error 65: expected SEMI
 error 65: expected expression
-error 91: expected expression
-error 91: expected SEMI
 error 92: expected expression
 error 93: expected SEMI
 error 93: expected expression
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_with_attr.rs b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_with_attr.rs
new file mode 100644
index 000000000..5daf1d7b0
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_with_attr.rs
@@ -0,0 +1,3 @@
+fn main() {
+    foo(#[attr] 92)
+}
diff --git a/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_with_attr.txt b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_with_attr.txt
new file mode 100644
index 000000000..8092d7009
--- /dev/null
+++ b/crates/ra_syntax/test_data/parser/inline/ok/0152_arg_with_attr.txt
@@ -0,0 +1,37 @@
+SOURCE_FILE@[0; 34)
+  FN_DEF@[0; 33)
+    FN_KW@[0; 2) "fn"
+    WHITESPACE@[2; 3) " "
+    NAME@[3; 7)
+      IDENT@[3; 7) "main"
+    PARAM_LIST@[7; 9)
+      L_PAREN@[7; 8) "("
+      R_PAREN@[8; 9) ")"
+    WHITESPACE@[9; 10) " "
+    BLOCK_EXPR@[10; 33)
+      BLOCK@[10; 33)
+        L_CURLY@[10; 11) "{"
+        WHITESPACE@[11; 16) "\n    "
+        CALL_EXPR@[16; 31)
+          PATH_EXPR@[16; 19)
+            PATH@[16; 19)
+              PATH_SEGMENT@[16; 19)
+                NAME_REF@[16; 19)
+                  IDENT@[16; 19) "foo"
+          ARG_LIST@[19; 31)
+            L_PAREN@[19; 20) "("
+            LITERAL@[20; 30)
+              ATTR@[20; 27)
+                POUND@[20; 21) "#"
+                L_BRACK@[21; 22) "["
+                PATH@[22; 26)
+                  PATH_SEGMENT@[22; 26)
+                    NAME_REF@[22; 26)
+                      IDENT@[22; 26) "attr"
+                R_BRACK@[26; 27) "]"
+              WHITESPACE@[27; 28) " "
+              INT_NUMBER@[28; 30) "92"
+            R_PAREN@[30; 31) ")"
+        WHITESPACE@[31; 32) "\n"
+        R_CURLY@[32; 33) "}"
+  WHITESPACE@[33; 34) "\n"
diff --git a/editors/emacs/rust-analyzer.el b/editors/emacs/rust-analyzer.el
index 8ba98bf61..06db4f15f 100644
--- a/editors/emacs/rust-analyzer.el
+++ b/editors/emacs/rust-analyzer.el
@@ -210,9 +210,9 @@
 ;; inlay hints
 (defun rust-analyzer--update-inlay-hints (buffer)
   (if (and (rust-analyzer--initialized?) (eq buffer (current-buffer)))
-    (lsp-send-request-async
-     (lsp-make-request "rust-analyzer/inlayHints"
-                       (list :textDocument (lsp--text-document-identifier)))
+    (lsp-request-async
+     "rust-analyzer/inlayHints"
+     (list :textDocument (lsp--text-document-identifier))
      (lambda (res)
        (remove-overlays (point-min) (point-max) 'rust-analyzer--inlay-hint t)
        (dolist (hint res)
@@ -221,9 +221,16 @@
                  (overlay (make-overlay beg end)))
            (overlay-put overlay 'rust-analyzer--inlay-hint t)
            (overlay-put overlay 'evaporate t)
-           (overlay-put overlay 'after-string (propertize (concat ": " label)
-                                                          'font-lock-face 'font-lock-comment-face)))))
-     'tick))
+           (cond
+            ((string= kind "TypeHint")
+             (overlay-put overlay 'after-string (propertize (concat ": " label)
+                                                            'font-lock-face 'font-lock-comment-face)))
+            ((string= kind "ParameterHint")
+             (overlay-put overlay 'before-string (propertize (concat label ": ")
+                                                            'font-lock-face 'font-lock-comment-face)))
+            )
+           )))
+     :mode 'tick))
   nil)
 
 (defvar-local rust-analyzer--inlay-hints-timer nil)
diff --git a/xtask/src/codegen/gen_syntax.rs b/xtask/src/codegen/gen_syntax.rs
index 19fea67d8..db05dcebb 100644
--- a/xtask/src/codegen/gen_syntax.rs
+++ b/xtask/src/codegen/gen_syntax.rs
@@ -1,4 +1,4 @@
-//! This module generate AST datatype used by rust-analyzer.
+//! This module generates AST datatype used by rust-analyzer.
 //!
 //! Specifically, it generates the `SyntaxKind` enum and a number of newtype
 //! wrappers around `SyntaxNode` which implement `ra_syntax::AstNode`.
diff --git a/xtask/src/lib.rs b/xtask/src/lib.rs
index 0a569cf5d..9b0afe8e0 100644
--- a/xtask/src/lib.rs
+++ b/xtask/src/lib.rs
@@ -53,6 +53,7 @@ fn reformat(text: impl std::fmt::Display) -> Result<String> {
     write!(rustfmt.stdin.take().unwrap(), "{}", text)?;
     let output = rustfmt.wait_with_output()?;
     let stdout = String::from_utf8(output.stdout)?;
+    // TODO: update the preable: replace ra_tools with the relevant path
     let preamble = "Generated file, do not edit by hand, see `crate/ra_tools/src/codegen`";
     Ok(format!("//! {}\n\n{}", preamble, stdout))
 }