4 files changed, 70 insertions, 25 deletions

diff --git a/Cargo.lock b/Cargo.lock
index 792e30494..3314ef70f 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -10,7 +10,7 @@ dependencies = [
 
 [[package]]
 name = "anyhow"
-version = "1.0.25"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -237,7 +237,7 @@ dependencies = [
  "crossbeam-channel 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-deque 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-epoch 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-queue 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "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)",
 ]
 
@@ -273,9 +273,10 @@ dependencies = [
 
 [[package]]
 name = "crossbeam-queue"
-version = "0.2.0"
+version = "0.2.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
  "crossbeam-utils 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -1334,7 +1335,7 @@ version = "1.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "crossbeam-deque 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "crossbeam-queue 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "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)",
@@ -1752,7 +1753,7 @@ dependencies = [
 name = "xtask"
 version = "0.1.0"
 dependencies = [
- "anyhow 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)",
+ "anyhow 1.0.26 (registry+https://github.com/rust-lang/crates.io-index)",
  "pico-args 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "proc-macro2 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "quote 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1771,7 +1772,7 @@ dependencies = [
 
 [metadata]
 "checksum aho-corasick 0.7.6 (registry+https://github.com/rust-lang/crates.io-index)" = "58fb5e95d83b38284460a5fda7d6470aa0b8844d283a0b614b8535e880800d2d"
-"checksum anyhow 1.0.25 (registry+https://github.com/rust-lang/crates.io-index)" = "9267dff192e68f3399525901e709a48c1d3982c9c072fa32f2127a0cb0babf14"
+"checksum anyhow 1.0.26 (registry+https://github.com/rust-lang/crates.io-index)" = "7825f6833612eb2414095684fcf6c635becf3ce97fe48cf6421321e93bfbd53c"
 "checksum anymap 0.12.1 (registry+https://github.com/rust-lang/crates.io-index)" = "33954243bd79057c2de7338850b85983a44588021f8a5fee574a8888c6de4344"
 "checksum arrayvec 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cff77d8686867eceff3105329d4698d96c2391c176d5d03adc90c7389162b5b8"
 "checksum atty 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)" = "1803c647a3ec87095e7ae7acfca019e98de5ec9a7d01343f611cf3152ed71a90"
@@ -1802,7 +1803,7 @@ dependencies = [
 "checksum crossbeam-channel 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "acec9a3b0b3559f15aee4f90746c4e5e293b701c0f7d3925d24e01645267b68c"
 "checksum crossbeam-deque 0.7.2 (registry+https://github.com/rust-lang/crates.io-index)" = "c3aa945d63861bfe624b55d153a39684da1e8c0bc8fba932f7ee3a3c16cea3ca"
 "checksum crossbeam-epoch 0.8.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5064ebdbf05ce3cb95e45c8b086f72263f4166b29b97f6baff7ef7fe047b55ac"
-"checksum crossbeam-queue 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "dfd6515864a82d2f877b42813d4553292c6659498c9a2aa31bab5a15243c2700"
+"checksum crossbeam-queue 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "c695eeca1e7173472a32221542ae469b3e9aac3a4fc81f7696bcad82029493db"
 "checksum crossbeam-utils 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ce446db02cdc3165b94ae73111e570793400d0794e46125cc4056c81cbb039f4"
 "checksum difference 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "524cbf6897b527295dff137cec09ecf3a05f4fddffd7dfcd1585403449e74198"
 "checksum drop_bomb 0.1.4 (registry+https://github.com/rust-lang/crates.io-index)" = "69b26e475fd29098530e709294e94e661974c851aed42512793f120fed4e199f"
diff --git a/crates/ra_hir_ty/src/display.rs b/crates/ra_hir_ty/src/display.rs
index dcca1bace..37def7c03 100644
--- a/crates/ra_hir_ty/src/display.rs
+++ b/crates/ra_hir_ty/src/display.rs
@@ -10,7 +10,7 @@ pub struct HirFormatter<'a, 'b, DB> {
     buf: String,
     curr_size: usize,
     max_size: Option<usize>,
-    should_display_default_types: bool,
+    omit_verbose_types: bool,
 }
 
 pub trait HirDisplay {
@@ -20,7 +20,7 @@ pub trait HirDisplay {
     where
         Self: Sized,
     {
-        HirDisplayWrapper(db, self, None, true)
+        HirDisplayWrapper(db, self, None, false)
     }
 
     fn display_truncated<'a, DB>(
@@ -31,7 +31,7 @@ pub trait HirDisplay {
     where
         Self: Sized,
     {
-        HirDisplayWrapper(db, self, max_size, false)
+        HirDisplayWrapper(db, self, max_size, true)
     }
 }
 
@@ -74,8 +74,8 @@ where
         }
     }
 
-    pub fn should_display_default_types(&self) -> bool {
-        self.should_display_default_types
+    pub fn omit_verbose_types(&self) -> bool {
+        self.omit_verbose_types
     }
 }
 
@@ -93,7 +93,7 @@ where
             buf: String::with_capacity(20),
             curr_size: 0,
             max_size: self.2,
-            should_display_default_types: self.3,
+            omit_verbose_types: self.3,
         })
     }
 }
diff --git a/crates/ra_hir_ty/src/lib.rs b/crates/ra_hir_ty/src/lib.rs
index 48abf97c9..55b6dd836 100644
--- a/crates/ra_hir_ty/src/lib.rs
+++ b/crates/ra_hir_ty/src/lib.rs
@@ -821,6 +821,8 @@ impl TypeWalk for Ty {
     }
 }
 
+const TYPE_HINT_TRUNCATION: &str = "…";
+
 impl HirDisplay for &Ty {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         HirDisplay::hir_fmt(*self, f)
@@ -830,7 +832,7 @@ impl HirDisplay for &Ty {
 impl HirDisplay for ApplicationTy {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         match self.ctor {
@@ -908,9 +910,7 @@ impl HirDisplay for ApplicationTy {
                     write!(f, "<")?;
 
                     let mut non_default_parameters = Vec::with_capacity(self.parameters.len());
-                    let parameters_to_write = if f.should_display_default_types() {
-                        self.parameters.0.as_ref()
-                    } else {
+                    let parameters_to_write = if f.omit_verbose_types() {
                         match self
                             .ctor
                             .as_generic_def()
@@ -935,6 +935,8 @@ impl HirDisplay for ApplicationTy {
                                 &non_default_parameters
                             }
                         }
+                    } else {
+                        self.parameters.0.as_ref()
                     };
 
                     f.write_joined(parameters_to_write, ", ")?;
@@ -959,9 +961,16 @@ impl HirDisplay for ApplicationTy {
                 let sig = self.parameters[0]
                     .callable_sig(f.db)
                     .expect("first closure parameter should contain signature");
-                write!(f, "|")?;
-                f.write_joined(sig.params(), ", ")?;
-                write!(f, "| -> {}", sig.ret().display(f.db))?;
+                let return_type_hint = sig.ret().display(f.db);
+                if sig.params().is_empty() {
+                    write!(f, "|| -> {}", return_type_hint)?;
+                } else if f.omit_verbose_types() {
+                    write!(f, "|{}| -> {}", TYPE_HINT_TRUNCATION, return_type_hint)?;
+                } else {
+                    write!(f, "|")?;
+                    f.write_joined(sig.params(), ", ")?;
+                    write!(f, "| -> {}", return_type_hint)?;
+                };
             }
         }
         Ok(())
@@ -971,7 +980,7 @@ impl HirDisplay for ApplicationTy {
 impl HirDisplay for ProjectionTy {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         let trait_name = f.db.trait_data(self.trait_(f.db)).name.clone();
@@ -989,7 +998,7 @@ impl HirDisplay for ProjectionTy {
 impl HirDisplay for Ty {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         match self {
@@ -1074,7 +1083,7 @@ impl HirDisplay for Ty {
 impl TraitRef {
     fn hir_fmt_ext(&self, f: &mut HirFormatter<impl HirDatabase>, use_as: bool) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         self.substs[0].hir_fmt(f)?;
@@ -1108,7 +1117,7 @@ impl HirDisplay for &GenericPredicate {
 impl HirDisplay for GenericPredicate {
     fn hir_fmt(&self, f: &mut HirFormatter<impl HirDatabase>) -> fmt::Result {
         if f.should_truncate() {
-            return write!(f, "…");
+            return write!(f, "{}", TYPE_HINT_TRUNCATION);
         }
 
         match self {
diff --git a/crates/ra_ide/src/inlay_hints.rs b/crates/ra_ide/src/inlay_hints.rs
index c5e406977..977aafc51 100644
--- a/crates/ra_ide/src/inlay_hints.rs
+++ b/crates/ra_ide/src/inlay_hints.rs
@@ -293,7 +293,7 @@ fn main() {
     }
 
     #[test]
-    fn closure_parameter() {
+    fn closure_parameters() {
         let (analysis, file_id) = single_file(
             r#"
 fn main() {
@@ -301,6 +301,11 @@ fn main() {
     (0..2).for_each(|increment| {
         start += increment;
     })
+
+    let multiply = |a, b, c, d| a * b * c * d;
+    let _: i32 = multiply(1, 2, 3, 4);
+
+    let return_42 = || 42;
 }"#,
         );
 
@@ -316,6 +321,36 @@ fn main() {
                 kind: TypeHint,
                 label: "i32",
             },
+            InlayHint {
+                range: [114; 122),
+                kind: TypeHint,
+                label: "|…| -> i32",
+            },
+            InlayHint {
+                range: [126; 127),
+                kind: TypeHint,
+                label: "i32",
+            },
+            InlayHint {
+                range: [129; 130),
+                kind: TypeHint,
+                label: "i32",
+            },
+            InlayHint {
+                range: [132; 133),
+                kind: TypeHint,
+                label: "i32",
+            },
+            InlayHint {
+                range: [135; 136),
+                kind: TypeHint,
+                label: "i32",
+            },
+            InlayHint {
+                range: [201; 210),
+                kind: TypeHint,
+                label: "|| -> i32",
+            },
         ]
         "###
         );