diff --git a/crates/rust-analyzer/src/diagnostics/to_proto.rs b/crates/rust-analyzer/src/diagnostics/to_proto.rs
index 7be3ef9841..97f3313521 100644
--- a/crates/rust-analyzer/src/diagnostics/to_proto.rs
+++ b/crates/rust-analyzer/src/diagnostics/to_proto.rs
@@ -118,6 +118,7 @@ fn map_rust_child_diagnostic(
                 changes: Some(edit_map),
                 document_changes: None,
             }),
+            is_preferred: Some(true),
         })
     }
 }
diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index 326977b626..d880570d28 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs
@@ -770,6 +770,7 @@ fn handle_fixes(
             group: None,
             kind: Some(CodeActionKind::QUICKFIX),
             edit: Some(edit),
+            is_preferred: Some(false),
         };
         res.push(action);
     }
diff --git a/crates/rust-analyzer/src/lsp_ext.rs b/crates/rust-analyzer/src/lsp_ext.rs
index e216966a98..13ebb18fbb 100644
--- a/crates/rust-analyzer/src/lsp_ext.rs
+++ b/crates/rust-analyzer/src/lsp_ext.rs
@@ -243,6 +243,7 @@ impl Request for CodeActionRequest {
 }
 
 #[derive(Debug, PartialEq, Clone, Default, Deserialize, Serialize)]
+#[serde(rename_all = "camelCase")]
 pub struct CodeAction {
     pub title: String,
     #[serde(skip_serializing_if = "Option::is_none")]
@@ -256,6 +257,8 @@ pub struct CodeAction {
     // pub command: Option<lsp_types::Command>,
     #[serde(skip_serializing_if = "Option::is_none")]
     pub edit: Option<SnippetWorkspaceEdit>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub is_preferred: Option<bool>,
 }
 
 #[derive(Debug, Eq, PartialEq, Clone, Default, Deserialize, Serialize)]
diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 783012c1a2..687432ddb1 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs
@@ -689,6 +689,7 @@ pub(crate) fn unresolved_code_action(
         group: assist.group.filter(|_| snap.config.client_caps.code_action_group).map(|gr| gr.0),
         kind: Some(code_action_kind(assist.id.1)),
         edit: None,
+        is_preferred: None,
     };
     Ok(res)
 }
diff --git a/crates/rust-analyzer/test_data/rustc_unused_variable.txt b/crates/rust-analyzer/test_data/rustc_unused_variable.txt
index 0846327572..74d91bc77c 100644
--- a/crates/rust-analyzer/test_data/rustc_unused_variable.txt
+++ b/crates/rust-analyzer/test_data/rustc_unused_variable.txt
@@ -65,6 +65,9 @@
                         document_changes: None,
                     },
                 ),
+                is_preferred: Some(
+                    true,
+                ),
             },
         ],
     },
diff --git a/crates/rust-analyzer/test_data/rustc_unused_variable_as_hint.txt b/crates/rust-analyzer/test_data/rustc_unused_variable_as_hint.txt
index d637923c50..8a420c9495 100644
--- a/crates/rust-analyzer/test_data/rustc_unused_variable_as_hint.txt
+++ b/crates/rust-analyzer/test_data/rustc_unused_variable_as_hint.txt
@@ -65,6 +65,9 @@
                         document_changes: None,
                     },
                 ),
+                is_preferred: Some(
+                    true,
+                ),
             },
         ],
     },
diff --git a/crates/rust-analyzer/test_data/rustc_unused_variable_as_info.txt b/crates/rust-analyzer/test_data/rustc_unused_variable_as_info.txt
index 6b48f16edb..79910660b7 100644
--- a/crates/rust-analyzer/test_data/rustc_unused_variable_as_info.txt
+++ b/crates/rust-analyzer/test_data/rustc_unused_variable_as_info.txt
@@ -65,6 +65,9 @@
                         document_changes: None,
                     },
                 ),
+                is_preferred: Some(
+                    true,
+                ),
             },
         ],
     },
diff --git a/crates/rust-analyzer/test_data/snap_multi_line_fix.txt b/crates/rust-analyzer/test_data/snap_multi_line_fix.txt
index 2c4cbea168..4f811ab64b 100644
--- a/crates/rust-analyzer/test_data/snap_multi_line_fix.txt
+++ b/crates/rust-analyzer/test_data/snap_multi_line_fix.txt
@@ -93,6 +93,9 @@
                         document_changes: None,
                     },
                 ),
+                is_preferred: Some(
+                    true,
+                ),
             },
         ],
     },
diff --git a/crates/rust-analyzer/tests/heavy_tests/main.rs b/crates/rust-analyzer/tests/heavy_tests/main.rs
index 7b908d30c2..f12e5a37f4 100644
--- a/crates/rust-analyzer/tests/heavy_tests/main.rs
+++ b/crates/rust-analyzer/tests/heavy_tests/main.rs
@@ -284,6 +284,7 @@ fn main() {}
                 }
               ]
             },
+            "isPreferred": false,
             "kind": "quickfix",
             "title": "Create module"
         }]),
@@ -355,6 +356,7 @@ fn main() {{}}
                 }
               ]
             },
+            "isPreferred": false,
             "kind": "quickfix",
             "title": "Create module"
         }]),