3 files changed, 184 insertions, 7 deletions

diff --git a/crates/rust-analyzer/src/lsp_ext.rs b/crates/rust-analyzer/src/lsp_ext.rs
index 75ea48892..1371f6cb4 100644
--- a/crates/rust-analyzer/src/lsp_ext.rs
+++ b/crates/rust-analyzer/src/lsp_ext.rs
@@ -273,8 +273,8 @@ impl Request for HoverRequest {
 pub struct Hover {
     #[serde(flatten)]
     pub hover: lsp_types::Hover,
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub actions: Option<Vec<CommandLinkGroup>>,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    pub actions: Vec<CommandLinkGroup>,
 }
 
 #[derive(Debug, PartialEq, Clone, Default, Deserialize, Serialize)]
diff --git a/crates/rust-analyzer/src/main_loop/handlers.rs b/crates/rust-analyzer/src/main_loop/handlers.rs
index 894df5837..3ff779702 100644
--- a/crates/rust-analyzer/src/main_loop/handlers.rs
+++ b/crates/rust-analyzer/src/main_loop/handlers.rs
@@ -555,7 +555,7 @@ pub fn handle_hover(
             }),
             range: Some(range),
         },
-        actions: Some(prepare_hover_actions(&snap, info.info.actions())),
+        actions: prepare_hover_actions(&snap, info.info.actions()),
     };
 
     Ok(Some(hover))
@@ -1170,10 +1170,7 @@ fn show_references_command(
 }
 
 fn to_command_link(command: Command, tooltip: String) -> lsp_ext::CommandLink {
-    lsp_ext::CommandLink {
-        tooltip: Some(tooltip),
-        command,
-    }
+    lsp_ext::CommandLink { tooltip: Some(tooltip), command }
 }
 
 fn show_impl_command_link(
diff --git a/crates/rust-analyzer/tests/heavy_tests/main.rs b/crates/rust-analyzer/tests/heavy_tests/main.rs
index ad3476310..78c6195d7 100644
--- a/crates/rust-analyzer/tests/heavy_tests/main.rs
+++ b/crates/rust-analyzer/tests/heavy_tests/main.rs
@@ -715,3 +715,183 @@ pub fn foo(_input: TokenStream) -> TokenStream {
     let value = res.get("contents").unwrap().get("value").unwrap().to_string();
     assert_eq!(value, r#""```rust\nfoo::Bar\n```\n\n```rust\nfn bar()\n```""#)
 }
+
+#[test]
+fn test_client_support_hover_actions() {
+    if skip_slow_tests() {
+        return;
+    }
+
+    let server = Project::with_fixture(
+        r#"
+//- Cargo.toml
+[package]
+name = "foo"
+version = "0.0.0"
+
+//- src/lib.rs
+struct Foo(u32);
+
+struct NoImpl(u32);
+
+impl Foo {
+    fn new() -> Self {
+        Self(1)
+    }
+}
+"#,
+    )
+    .with_config(|config| {
+        config.client_caps.hover_actions = true;
+    })
+    .server();
+
+    server.wait_until_workspace_is_loaded();
+
+    // has 1 implementation
+    server.request::<HoverRequest>(
+        HoverParams {
+            text_document_position_params: TextDocumentPositionParams::new(
+                server.doc_id("src/lib.rs"),
+                Position::new(0, 9),
+            ),
+            work_done_progress_params: Default::default(),
+        },
+        json!({
+            "actions": [{
+                "commands": [{
+                    "arguments": [
+                      "file:///[..]src/lib.rs",
+                      {
+                        "character": 7,
+                        "line": 0
+                      },
+                      [{
+                          "range": { "end": { "character": 1, "line": 8 }, "start": { "character": 0, "line": 4 } },
+                          "uri": "file:///[..]src/lib.rs"
+                      }]
+                    ],
+                    "command": "rust-analyzer.showReferences",
+                    "title": "1 implementation",
+                    "tooltip": "Go to implementations"
+                }]
+            }],
+            "contents": { "kind": "markdown", "value": "```rust\nfoo\n```\n\n```rust\nstruct Foo\n```" },
+            "range": { "end": { "character": 10, "line": 0 }, "start": { "character": 7, "line": 0 } }
+        })
+    );
+
+    // no hover
+    server.request::<HoverRequest>(
+        HoverParams {
+            text_document_position_params: TextDocumentPositionParams::new(
+                server.doc_id("src/lib.rs"),
+                Position::new(1, 0),
+            ),
+            work_done_progress_params: Default::default(),
+        },
+        json!(null),
+    );
+
+    // no implementations
+    server.request::<HoverRequest>(
+        HoverParams {
+            text_document_position_params: TextDocumentPositionParams::new(
+                server.doc_id("src/lib.rs"),
+                Position::new(2, 12),
+            ),
+            work_done_progress_params: Default::default(),
+        },
+        json!({
+            "actions": [{
+                "commands": [{
+                    "arguments": [
+                      "file:///[..]src/lib.rs",
+                      { "character": 7, "line": 2 },
+                      []
+                    ],
+                    "command": "rust-analyzer.showReferences",
+                    "title": "0 implementations",
+                    "tooltip": "Go to implementations"
+                }]
+            }],
+            "contents": { "kind": "markdown", "value": "```rust\nfoo\n```\n\n```rust\nstruct NoImpl\n```" },
+            "range": { "end": { "character": 13, "line": 2 }, "start": { "character": 7, "line": 2 } }
+        })
+    );
+}
+
+#[test]
+fn test_client_does_not_support_hover_actions() {
+    if skip_slow_tests() {
+        return;
+    }
+
+    let server = Project::with_fixture(
+        r#"
+//- Cargo.toml
+[package]
+name = "foo"
+version = "0.0.0"
+
+//- src/lib.rs
+struct Foo(u32);
+
+struct NoImpl(u32);
+
+impl Foo {
+    fn new() -> Self {
+        Self(1)
+    }
+}
+"#,
+    )
+    .with_config(|config| {
+        config.client_caps.hover_actions = false;
+    })
+    .server();
+
+    server.wait_until_workspace_is_loaded();
+
+    // has 1 implementation
+    server.request::<HoverRequest>(
+        HoverParams {
+            text_document_position_params: TextDocumentPositionParams::new(
+                server.doc_id("src/lib.rs"),
+                Position::new(0, 9),
+            ),
+            work_done_progress_params: Default::default(),
+        },
+        json!({
+            "contents": { "kind": "markdown", "value": "```rust\nfoo\n```\n\n```rust\nstruct Foo\n```" },
+            "range": { "end": { "character": 10, "line": 0 }, "start": { "character": 7, "line": 0 } }
+        })
+    );
+
+    // no hover
+    server.request::<HoverRequest>(
+        HoverParams {
+            text_document_position_params: TextDocumentPositionParams::new(
+                server.doc_id("src/lib.rs"),
+                Position::new(1, 0),
+            ),
+            work_done_progress_params: Default::default(),
+        },
+        json!(null),
+    );
+
+    // no implementations
+    server.request::<HoverRequest>(
+        HoverParams {
+            text_document_position_params: TextDocumentPositionParams::new(
+                server.doc_id("src/lib.rs"),
+                Position::new(2, 12),
+            ),
+            work_done_progress_params: Default::default(),
+        },
+        json!({
+            "contents": { "kind": "markdown", "value": "```rust\nfoo\n```\n\n```rust\nstruct NoImpl\n```" },
+            "range": { "end": { "character": 13, "line": 2 }, "start": { "character": 7, "line": 2 } }
+        })
+    );
+}