11 files changed, 154 insertions, 67 deletions

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"