do not use associated types placeholder for inlay hint

Signed-off-by: Benjamin Coenen <[email protected]>

6 files changed, 108 insertions, 155 deletions

diff --git a/crates/hir_ty/src/display.rs b/crates/hir_ty/src/display.rs
index f1232a72f..ddfd8c8af 100644
--- a/crates/hir_ty/src/display.rs
+++ b/crates/hir_ty/src/display.rs
@@ -74,9 +74,29 @@ pub trait HirDisplay {
             curr_size: 0,
             max_size: None,
             omit_verbose_types: false,
-            #[cfg(not(test))]
             display_target: DisplayTarget::SourceCode { module_id },
-            #[cfg(test)]
+        }) {
+            Ok(()) => {}
+            Err(HirDisplayError::FmtError) => panic!("Writing to String can't fail!"),
+            Err(HirDisplayError::DisplaySourceCodeError(e)) => return Err(e),
+        };
+        Ok(result)
+    }
+
+    /// Returns a String representation of `self` for test purposes
+    fn display_test<'a>(
+        &'a self,
+        db: &'a dyn HirDatabase,
+        module_id: ModuleId,
+    ) -> Result<String, DisplaySourceCodeError> {
+        let mut result = String::new();
+        match self.hir_fmt(&mut HirFormatter {
+            db,
+            fmt: &mut result,
+            buf: String::with_capacity(20),
+            curr_size: 0,
+            max_size: None,
+            omit_verbose_types: false,
             display_target: DisplayTarget::Test { module_id },
         }) {
             Ok(()) => {}
@@ -138,7 +158,6 @@ enum DisplayTarget {
     /// The generated code should compile, so paths need to be qualified.
     SourceCode { module_id: ModuleId },
     /// Only for test purpose to keep real types
-    #[cfg(test)]
     Test { module_id: ModuleId },
 }
 
@@ -147,14 +166,7 @@ impl DisplayTarget {
         matches!(self, Self::SourceCode {..})
     }
     fn is_test(&self) -> bool {
-        #[cfg(test)]
-        {
-            matches!(self, Self::Test {..})
-        }
-        #[cfg(not(test))]
-        {
-            false
-        }
+        matches!(self, Self::Test {..})
     }
 }
 
@@ -344,21 +356,7 @@ impl HirDisplay for ApplicationTy {
                         };
                         write!(f, "{}", name)?;
                     }
-                    DisplayTarget::SourceCode { module_id } => {
-                        if let Some(path) = find_path::find_path(
-                            f.db.upcast(),
-                            ItemInNs::Types(def_id.into()),
-                            module_id,
-                        ) {
-                            write!(f, "{}", path)?;
-                        } else {
-                            return Err(HirDisplayError::DisplaySourceCodeError(
-                                DisplaySourceCodeError::PathNotFound,
-                            ));
-                        }
-                    }
-                    #[cfg(test)]
-                    DisplayTarget::Test { module_id } => {
+                    DisplayTarget::SourceCode { module_id } | DisplayTarget::Test { module_id } => {
                         if let Some(path) = find_path::find_path(
                             f.db.upcast(),
                             ItemInNs::Types(def_id.into()),
@@ -374,40 +372,38 @@ impl HirDisplay for ApplicationTy {
                 }
 
                 if self.parameters.len() > 0 {
-                    let parameters_to_write = if f.display_target.is_source_code()
-                        || f.display_target.is_test()
-                        || f.omit_verbose_types()
-                    {
-                        match self
-                            .ctor
-                            .as_generic_def()
-                            .map(|generic_def_id| f.db.generic_defaults(generic_def_id))
-                            .filter(|defaults| !defaults.is_empty())
-                        {
-                            None => self.parameters.0.as_ref(),
-                            Some(default_parameters) => {
-                                let mut default_from = 0;
-                                for (i, parameter) in self.parameters.iter().enumerate() {
-                                    match (parameter, default_parameters.get(i)) {
-                                        (&Ty::Unknown, _) | (_, None) => {
-                                            default_from = i + 1;
-                                        }
-                                        (_, Some(default_parameter)) => {
-                                            let actual_default = default_parameter
-                                                .clone()
-                                                .subst(&self.parameters.prefix(i));
-                                            if parameter != &actual_default {
+                    let parameters_to_write =
+                        if f.display_target.is_source_code() || f.omit_verbose_types() {
+                            match self
+                                .ctor
+                                .as_generic_def()
+                                .map(|generic_def_id| f.db.generic_defaults(generic_def_id))
+                                .filter(|defaults| !defaults.is_empty())
+                            {
+                                None => self.parameters.0.as_ref(),
+                                Some(default_parameters) => {
+                                    let mut default_from = 0;
+                                    for (i, parameter) in self.parameters.iter().enumerate() {
+                                        match (parameter, default_parameters.get(i)) {
+                                            (&Ty::Unknown, _) | (_, None) => {
                                                 default_from = i + 1;
                                             }
+                                            (_, Some(default_parameter)) => {
+                                                let actual_default = default_parameter
+                                                    .clone()
+                                                    .subst(&self.parameters.prefix(i));
+                                                if parameter != &actual_default {
+                                                    default_from = i + 1;
+                                                }
+                                            }
                                         }
                                     }
+                                    &self.parameters.0[0..default_from]
                                 }
-                                &self.parameters.0[0..default_from]
                             }
-                        }
-                    } else {
-                        self.parameters.0.as_ref()
-                    };
+                        } else {
+                            self.parameters.0.as_ref()
+                        };
                     if !parameters_to_write.is_empty() {
                         write!(f, "<")?;
                         f.write_joined(parameters_to_write, ", ")?;
diff --git a/crates/hir_ty/src/tests.rs b/crates/hir_ty/src/tests.rs
index 0445efc9e..510baadf2 100644
--- a/crates/hir_ty/src/tests.rs
+++ b/crates/hir_ty/src/tests.rs
@@ -157,13 +157,14 @@ fn infer_with_mismatches(content: &str, include_mismatches: bool) -> String {
                 (node.value.text_range(), node.value.text().to_string().replace("\n", " "))
             };
             let macro_prefix = if node.file_id != file_id.into() { "!" } else { "" };
+            let module = db.module_for_file(node.file_id.original_file(&db));
             format_to!(
                 buf,
                 "{}{:?} '{}': {}\n",
                 macro_prefix,
                 range,
                 ellipsize(text, 15),
-                ty.display(&db)
+                ty.display_test(&db, module).unwrap()
             );
         }
         if include_mismatches {
@@ -174,13 +175,14 @@ fn infer_with_mismatches(content: &str, include_mismatches: bool) -> String {
             for (src_ptr, mismatch) in &mismatches {
                 let range = src_ptr.value.text_range();
                 let macro_prefix = if src_ptr.file_id != file_id.into() { "!" } else { "" };
+                let module = db.module_for_file(src_ptr.file_id.original_file(&db));
                 format_to!(
                     buf,
                     "{}{:?}: expected {}, got {}\n",
                     macro_prefix,
                     range,
-                    mismatch.expected.display(&db),
-                    mismatch.actual.display(&db),
+                    mismatch.expected.display_test(&db, module).unwrap(),
+                    mismatch.actual.display_test(&db, module).unwrap(),
                 );
             }
         }
diff --git a/crates/hir_ty/src/tests/method_resolution.rs b/crates/hir_ty/src/tests/method_resolution.rs
index 0f17ff151..596d4f182 100644
--- a/crates/hir_ty/src/tests/method_resolution.rs
+++ b/crates/hir_ty/src/tests/method_resolution.rs
@@ -108,16 +108,16 @@ fn infer_associated_method_with_modules() {
     check_infer(
         r#"
         mod a {
-            struct A;
+            pub struct A;
             impl A { pub fn thing() -> A { A {} }}
         }
 
         mod b {
-            struct B;
+            pub struct B;
             impl B { pub fn thing() -> u32 { 99 }}
 
-            mod c {
-                struct C;
+            pub mod c {
+                pub struct C;
                 impl C { pub fn thing() -> C { C {} }}
             }
         }
@@ -130,22 +130,22 @@ fn infer_associated_method_with_modules() {
         }
         "#,
         expect![[r#"
-            55..63 '{ A {} }': A
-            57..61 'A {}': A
-            125..131 '{ 99 }': u32
-            127..129 '99': u32
-            201..209 '{ C {} }': C
-            203..207 'C {}': C
-            240..324 '{     ...g(); }': ()
-            250..251 'x': A
-            254..265 'a::A::thing': fn thing() -> A
-            254..267 'a::A::thing()': A
-            277..278 'y': u32
-            281..292 'b::B::thing': fn thing() -> u32
-            281..294 'b::B::thing()': u32
-            304..305 'z': C
-            308..319 'c::C::thing': fn thing() -> C
-            308..321 'c::C::thing()': C
+            59..67 '{ A {} }': a::A
+            61..65 'A {}': a::A
+            133..139 '{ 99 }': u32
+            135..137 '99': u32
+            217..225 '{ C {} }': c::C
+            219..223 'C {}': c::C
+            256..340 '{     ...g(); }': ()
+            266..267 'x': a::A
+            270..281 'a::A::thing': fn thing() -> A
+            270..283 'a::A::thing()': a::A
+            293..294 'y': u32
+            297..308 'b::B::thing': fn thing() -> u32
+            297..310 'b::B::thing()': u32
+            320..321 'z': c::C
+            324..335 'c::C::thing': fn thing() -> C
+            324..337 'c::C::thing()': c::C
         "#]],
     );
 }
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs
index 66e171f24..42d08f12c 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -831,11 +831,11 @@ fn issue_4966() {
             356..362 'repeat': Repeat<Map<|&f64| -> f64>>
             365..390 'Repeat...nner }': Repeat<Map<|&f64| -> f64>>
             383..388 'inner': Map<|&f64| -> f64>
-            401..404 'vec': Vec<<Repeat<Map<|&f64| -> f64>> as IntoIterator>::Item>
-            407..416 'from_iter': fn from_iter<<Repeat<Map<|&f64| -> f64>> as IntoIterator>::Item, Repeat<Map<|&f64| -> f64>>>(Repeat<Map<|&f64| -> f64>>) -> Vec<<Repeat<Map<|&f64| -> f64>> as IntoIterator>::Item>
-            407..424 'from_i...epeat)': Vec<<Repeat<Map<|&f64| -> f64>> as IntoIterator>::Item>
+            401..404 'vec': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
+            407..416 'from_iter': fn from_iter<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>, Repeat<Map<|&f64| -> f64>>>(Repeat<Map<|&f64| -> f64>>) -> Vec<<Repeat<Map<|&f64| -> f64>> as IntoIterator>::Item>
+            407..424 'from_i...epeat)': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
             417..423 'repeat': Repeat<Map<|&f64| -> f64>>
-            431..434 'vec': Vec<<Repeat<Map<|&f64| -> f64>> as IntoIterator>::Item>
+            431..434 'vec': Vec<IntoIterator::Item<Repeat<Map<|&f64| -> f64>>>>
             431..444 'vec.foo_bar()': {unknown}
         "#]],
     );
diff --git a/crates/hir_ty/src/tests/traits.rs b/crates/hir_ty/src/tests/traits.rs
index e98d7c064..4d193dea9 100644
--- a/crates/hir_ty/src/tests/traits.rs
+++ b/crates/hir_ty/src/tests/traits.rs
@@ -1,7 +1,7 @@
 use expect_test::expect;
 use test_utils::mark;
 
-use super::{check_infer, check_infer_with_mismatches, check_types, check_types_source_code};
+use super::{check_infer, check_infer_with_mismatches, check_types};
 
 #[test]
 fn infer_await() {
@@ -384,12 +384,12 @@ fn infer_project_associated_type() {
             108..261 '{     ...ter; }': ()
             118..119 'x': u32
             145..146 '1': u32
-            156..157 'y': <T as Iterable>::Item
-            183..192 'no_matter': <T as Iterable>::Item
-            202..203 'z': <T as Iterable>::Item
-            215..224 'no_matter': <T as Iterable>::Item
-            234..235 'a': <T as Iterable>::Item
-            249..258 'no_matter': <T as Iterable>::Item
+            156..157 'y': Iterable::Item<T>
+            183..192 'no_matter': Iterable::Item<T>
+            202..203 'z': Iterable::Item<T>
+            215..224 'no_matter': Iterable::Item<T>
+            234..235 'a': Iterable::Item<T>
+            249..258 'no_matter': Iterable::Item<T>
         "#]],
     );
 }
@@ -946,45 +946,6 @@ fn test<T: ApplyL>(t: T) {
 }
 
 #[test]
-fn associated_type_placeholder() {
-    check_types_source_code(
-        r#"
-pub trait ApplyL {
-    type Out;
-}
-
-pub struct RefMutL<T>;
-
-impl<T> ApplyL for RefMutL<T> {
-    type Out = <T as ApplyL>::Out;
-}
-
-fn test<T: ApplyL>() {
-    let y: <RefMutL<T> as ApplyL>::Out = no_matter;
-    y;
-} //^ ApplyL::Out<T>
-"#,
-    );
-}
-
-#[test]
-fn associated_type_placeholder_2() {
-    check_types_source_code(
-        r#"
-pub trait ApplyL {
-    type Out;
-}
-fn foo<T: ApplyL>(t: T) -> <T as ApplyL>::Out;
-
-fn test<T: ApplyL>(t: T) {
-    let y = foo(t);
-    y;
-} //^ ApplyL::Out<T>
-"#,
-    );
-}
-
-#[test]
 fn argument_impl_trait() {
     check_infer_with_mismatches(
         r#"
@@ -2158,7 +2119,7 @@ fn unselected_projection_on_impl_self() {
         "#,
         expect![[r#"
             40..44 'self': &Self
-            46..47 'x': <Self as Trait>::Item
+            46..47 'x': Trait::Item<Self>
             126..130 'self': &S
             132..133 'x': u32
             147..161 '{ let y = x; }': ()
@@ -3189,30 +3150,3 @@ fn test() {
     "#,
     );
 }
-
-#[test]
-fn infer_call_method_return_associated_types_with_generic() {
-    check_infer(
-        r#"
-        pub trait Default {
-            fn default() -> Self;
-        }
-        pub trait Foo {
-            type Bar: Default;
-        }
-
-        pub fn quux<T: Foo>() -> T::Bar {
-            let y = Default::default();
-
-            y
-        }
-        "#,
-        expect![[r#"
-            122..164 '{     ...   y }': <T as Foo>::Bar
-            132..133 'y': <T as Foo>::Bar
-            136..152 'Defaul...efault': fn default<<T as Foo>::Bar>() -> <T as Foo>::Bar
-            136..154 'Defaul...ault()': <T as Foo>::Bar
-            161..162 'y': <T as Foo>::Bar
-        "#]],
-    );
-}
diff --git a/crates/ide/src/inlay_hints.rs b/crates/ide/src/inlay_hints.rs
index 49d8e4ae1..adb93efd7 100644
--- a/crates/ide/src/inlay_hints.rs
+++ b/crates/ide/src/inlay_hints.rs
@@ -1235,4 +1235,25 @@ fn main() {
 "#,
         );
     }
+
+    #[test]
+    fn infer_call_method_return_associated_types_with_generic() {
+        check(
+            r#"
+            pub trait Default {
+                fn default() -> Self;
+            }
+            pub trait Foo {
+                type Bar: Default;
+            }
+
+            pub fn quux<T: Foo>() -> T::Bar {
+                let y = Default::default();
+                  //^ <T as Foo>::Bar
+
+                y
+            }
+            "#,
+        );
+    }
 }