5 files changed, 55 insertions, 4 deletions

diff --git a/crates/hir_def/src/item_tree.rs b/crates/hir_def/src/item_tree.rs
index c6ada271e..b08167281 100644
--- a/crates/hir_def/src/item_tree.rs
+++ b/crates/hir_def/src/item_tree.rs
@@ -246,7 +246,10 @@ struct GenericParamsStorage {
 
 impl GenericParamsStorage {
     fn alloc(&mut self, params: GenericParams) -> GenericParamsId {
-        if params.types.is_empty() && params.where_predicates.is_empty() {
+        if params.types.is_empty()
+            && params.lifetimes.is_empty()
+            && params.where_predicates.is_empty()
+        {
             return GenericParamsId::EMPTY;
         }
 
diff --git a/crates/hir_ty/src/infer/expr.rs b/crates/hir_ty/src/infer/expr.rs
index ca005bc99..2cdce2cef 100644
--- a/crates/hir_ty/src/infer/expr.rs
+++ b/crates/hir_ty/src/infer/expr.rs
@@ -856,7 +856,12 @@ impl<'a> InferenceContext<'a> {
         // handle provided type arguments
         if let Some(generic_args) = generic_args {
             // if args are provided, it should be all of them, but we can't rely on that
-            for arg in generic_args.args.iter().take(type_params) {
+            for arg in generic_args
+                .args
+                .iter()
+                .filter(|arg| matches!(arg, GenericArg::Type(_)))
+                .take(type_params)
+            {
                 match arg {
                     GenericArg::Type(type_ref) => {
                         let ty = self.make_ty(type_ref);
diff --git a/crates/hir_ty/src/lower.rs b/crates/hir_ty/src/lower.rs
index 92f779360..8392cb770 100644
--- a/crates/hir_ty/src/lower.rs
+++ b/crates/hir_ty/src/lower.rs
@@ -565,7 +565,13 @@ fn substs_from_path_segment(
             if generic_args.has_self_type { self_params + type_params } else { type_params };
         let skip = if generic_args.has_self_type && self_params == 0 { 1 } else { 0 };
         // if args are provided, it should be all of them, but we can't rely on that
-        for arg in generic_args.args.iter().skip(skip).take(expected_num) {
+        for arg in generic_args
+            .args
+            .iter()
+            .filter(|arg| matches!(arg, GenericArg::Type(_)))
+            .skip(skip)
+            .take(expected_num)
+        {
             match arg {
                 GenericArg::Type(type_ref) => {
                     had_explicit_type_args = true;
diff --git a/crates/hir_ty/src/tests/regression.rs b/crates/hir_ty/src/tests/regression.rs
index 8cf4e7012..da8170417 100644
--- a/crates/hir_ty/src/tests/regression.rs
+++ b/crates/hir_ty/src/tests/regression.rs
@@ -883,3 +883,40 @@ fn issue_6628() {
         "#]],
     );
 }
+
+#[test]
+fn issue_6852() {
+    check_infer(
+        r#"
+        #[lang = "deref"]
+        pub trait Deref {
+            type Target;
+        }
+
+        struct BufWriter {}
+
+        struct Mutex<T> {}
+        struct MutexGuard<'a, T> {}
+        impl<T> Mutex<T> {
+            fn lock(&self) -> MutexGuard<'_, T> {}
+        }
+        impl<'a, T: 'a> Deref for MutexGuard<'a, T> {
+            type Target = T;
+        }
+        fn flush(&self) {
+            let w: &Mutex<BufWriter>;
+            *(w.lock());
+        }
+        "#,
+        expect![[r#"
+            156..160 'self': &Mutex<T>
+            183..185 '{}': ()
+            267..271 'self': &{unknown}
+            273..323 '{     ...()); }': ()
+            283..284 'w': &Mutex<BufWriter>
+            309..320 '*(w.lock())': BufWriter
+            311..312 'w': &Mutex<BufWriter>
+            311..319 'w.lock()': MutexGuard<BufWriter>
+        "#]],
+    );
+}
diff --git a/crates/project_model/src/sysroot.rs b/crates/project_model/src/sysroot.rs
index f0a43eaf6..95b622715 100644
--- a/crates/project_model/src/sysroot.rs
+++ b/crates/project_model/src/sysroot.rs
@@ -143,7 +143,7 @@ fn discover_sysroot_src_dir(current_dir: &AbsPath) -> Result<AbsPathBuf> {
 can't load standard library from sysroot
 {}
 (discovered via `rustc --print sysroot`)
-try running `rustup component add rust-src` or set `RUST_SRC_PATH`",
+try installing the Rust source the same way you installed rustc",
                 sysroot_path.display(),
             )
         })