From 0e771915faf057ec4561224b75ec9b5be93d71c8 Mon Sep 17 00:00:00 2001
From: Aleksey Kladov <aleksey.kladov@gmail.com>
Date: Wed, 20 Nov 2019 11:42:58 +0300
Subject: Allow non-path default type parameters

---
 crates/ra_hir/src/generics.rs | 11 ++++-------
 crates/ra_hir/src/ty/lower.rs |  4 +---
 crates/ra_hir/src/ty/tests.rs | 24 ++++++++++++++++++++++++
 3 files changed, 29 insertions(+), 10 deletions(-)

(limited to 'crates/ra_hir')

diff --git a/crates/ra_hir/src/generics.rs b/crates/ra_hir/src/generics.rs
index 8925ba3a9..78fab1a13 100644
--- a/crates/ra_hir/src/generics.rs
+++ b/crates/ra_hir/src/generics.rs
@@ -5,12 +5,9 @@
 
 use std::sync::Arc;
 
-use hir_def::{
-    path::Path,
-    type_ref::{TypeBound, TypeRef},
-};
+use hir_def::type_ref::{TypeBound, TypeRef};
 use hir_expand::name::{self, AsName};
-use ra_syntax::ast::{self, DefaultTypeParamOwner, NameOwner, TypeBoundsOwner, TypeParamsOwner};
+use ra_syntax::ast::{self, NameOwner, TypeBoundsOwner, TypeParamsOwner};
 
 use crate::{
     db::{AstDatabase, DefDatabase, HirDatabase},
@@ -24,7 +21,7 @@ pub struct GenericParam {
     // FIXME: give generic params proper IDs
     pub idx: u32,
     pub name: Name,
-    pub default: Option<Path>,
+    pub default: Option<TypeRef>,
 }
 
 /// Data about the generic parameters of a function, struct, impl, etc.
@@ -140,7 +137,7 @@ impl GenericParams {
         for (idx, type_param) in params.type_params().enumerate() {
             let name = type_param.name().map_or_else(Name::missing, |it| it.as_name());
             // FIXME: Use `Path::from_src`
-            let default = type_param.default_type().and_then(|t| t.path()).and_then(Path::from_ast);
+            let default = type_param.default_type().map(TypeRef::from_ast);
 
             let param = GenericParam { idx: idx as u32 + start, name: name.clone(), default };
             self.params.push(param);
diff --git a/crates/ra_hir/src/ty/lower.rs b/crates/ra_hir/src/ty/lower.rs
index de3c56097..03db38605 100644
--- a/crates/ra_hir/src/ty/lower.rs
+++ b/crates/ra_hir/src/ty/lower.rs
@@ -611,9 +611,7 @@ pub(crate) fn generic_defaults_query(db: &impl HirDatabase, def: GenericDef) ->
     let defaults = generic_params
         .params_including_parent()
         .into_iter()
-        .map(|p| {
-            p.default.as_ref().map_or(Ty::Unknown, |path| Ty::from_hir_path(db, &resolver, path))
-        })
+        .map(|p| p.default.as_ref().map_or(Ty::Unknown, |t| Ty::from_hir(db, &resolver, t)))
         .collect();
 
     Substs(defaults)
diff --git a/crates/ra_hir/src/ty/tests.rs b/crates/ra_hir/src/ty/tests.rs
index c1024d03c..abfaffb5e 100644
--- a/crates/ra_hir/src/ty/tests.rs
+++ b/crates/ra_hir/src/ty/tests.rs
@@ -1979,6 +1979,30 @@ fn test() {
     );
 }
 
+#[test]
+fn infer_associated_method_generics_with_default_tuple_param() {
+    let t = type_at(
+        r#"
+//- /main.rs
+struct Gen<T=()> {
+    val: T
+}
+
+impl<T> Gen<T> {
+    pub fn make() -> Gen<T> {
+        loop { }
+    }
+}
+
+fn test() {
+    let a = Gen::make();
+    a.val<|>;
+}
+"#,
+    );
+    assert_eq!(t, "()");
+}
+
 #[test]
 fn infer_associated_method_generics_without_args() {
     assert_snapshot!(
-- 
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