rust-analyzer

diff --git a/crates/rust-analyzer/src/from_proto.rs b/crates/rust-analyzer/src/from_proto.rs
index 712d5a9c27..a95836edda 100644
--- a/crates/rust-analyzer/src/from_proto.rs
+++ b/crates/rust-analyzer/src/from_proto.rs

@@ -10,7 +10,9 @@ use crate::{

from_json,

global_state::GlobalStateSnapshot,

line_index::{LineIndex, OffsetEncoding},

- lsp_ext, Result,

+ lsp_ext,

+ lsp_utils::invalid_params_error,

+ Result,

};

pub(crate) fn abs_path(url: &lsp_types::Url) -> Result<AbsPathBuf> {

@@ -85,7 +87,8 @@ pub(crate) fn annotation(

snap: &GlobalStateSnapshot,

code_lens: lsp_types::CodeLens,

) -> Result<Annotation> {

- let data = code_lens.data.unwrap();

+ let data =

+ code_lens.data.ok_or_else(|| invalid_params_error("code lens without data".to_string()))?;

let resolve = from_json::<lsp_ext::CodeLensResolveData>("CodeLensResolveData", data)?;

match resolve {

diff --git a/crates/rust-analyzer/src/handlers.rs b/crates/rust-analyzer/src/handlers.rs
index de96816f44..9de059a2c3 100644
--- a/crates/rust-analyzer/src/handlers.rs
+++ b/crates/rust-analyzer/src/handlers.rs

@@ -40,7 +40,7 @@ use crate::{

self, InlayHint, InlayHintsParams, PositionOrRange, ViewCrateGraphParams,

WorkspaceSymbolParams,

- lsp_utils::all_edits_are_disjoint,

+ lsp_utils::{all_edits_are_disjoint, invalid_params_error},

to_proto, LspError, Result,

};

@@ -767,9 +767,8 @@ pub(crate) fn handle_completion_resolve(

let _p = profile::span("handle_completion_resolve");

if !all_edits_are_disjoint(&original_completion, &[]) {

- return Err(LspError::new(

- ErrorCode::InvalidParams as i32,

- "Received a completion with overlapping edits, this is not LSP-compliant".into(),

+ return Err(invalid_params_error(

+ "Received a completion with overlapping edits, this is not LSP-compliant".to_string(),

)

.into());

}

@@ -1038,7 +1037,7 @@ pub(crate) fn handle_code_action_resolve(

let _p = profile::span("handle_code_action_resolve");

let params = match code_action.data.take() {

Some(it) => it,

- None => Err("can't resolve code action without data")?,

+ None => return Err(invalid_params_error(format!("code action without data")).into()),

};

let file_id = from_proto::file_id(&snap, &params.code_action_params.text_document.uri)?;

@@ -1056,10 +1055,10 @@ pub(crate) fn handle_code_action_resolve(

let (assist_index, assist_resolve) = match parse_action_id(&params.id) {

Ok(parsed_data) => parsed_data,

Err(e) => {

- return Err(LspError::new(

- ErrorCode::InvalidParams as i32,

- format!("Failed to parse action id string '{}': {}", params.id, e),

- )

+ return Err(invalid_params_error(format!(

+ "Failed to parse action id string '{}': {}",

+ params.id, e

+ ))

.into())

}

};

@@ -1076,23 +1075,17 @@ pub(crate) fn handle_code_action_resolve(

let assist = match assists.get(assist_index) {

Some(assist) => assist,

- None => return Err(LspError::new(

- ErrorCode::InvalidParams as i32,

- format!(

- "Failed to find the assist for index {} provided by the resolve request. Resolve request assist id: {}",

- assist_index, params.id,

- ),

- )

+ None => return Err(invalid_params_error(format!(

+ "Failed to find the assist for index {} provided by the resolve request. Resolve request assist id: {}",

+ assist_index, params.id,

+ ))

.into())

};

if assist.id.0 != expected_assist_id || assist.id.1 != expected_kind {

- return Err(LspError::new(

- ErrorCode::InvalidParams as i32,

- format!(

- "Mismatching assist at index {} for the resolve parameters given. Resolve request assist id: {}, actual id: {:?}.",

- assist_index, params.id, assist.id

- ),

- )

+ return Err(invalid_params_error(format!(

+ "Mismatching assist at index {} for the resolve parameters given. Resolve request assist id: {}, actual id: {:?}.",

+ assist_index, params.id, assist.id

+ ))

.into());

}

let edit = to_proto::code_action(&snap, assist.clone(), None)?.edit;

diff --git a/crates/rust-analyzer/src/lsp_utils.rs b/crates/rust-analyzer/src/lsp_utils.rs
index 29fa3e2d0e..09178521b5 100644
--- a/crates/rust-analyzer/src/lsp_utils.rs
+++ b/crates/rust-analyzer/src/lsp_utils.rs

@@ -8,8 +8,13 @@ use crate::{

from_proto,

global_state::GlobalState,

line_index::{LineEndings, LineIndex, OffsetEncoding},

+ LspError,

};

+pub(crate) fn invalid_params_error(message: String) -> LspError {

+ LspError { code: lsp_server::ErrorCode::InvalidParams as i32, message }

pub(crate) fn is_cancelled(e: &(dyn Error + 'static)) -> bool {

e.downcast_ref::<Cancelled>().is_some()

}

diff --git a/crates/rust-analyzer/src/to_proto.rs b/crates/rust-analyzer/src/to_proto.rs
index 8dcfff5c71..277476981f 100644
--- a/crates/rust-analyzer/src/to_proto.rs
+++ b/crates/rust-analyzer/src/to_proto.rs

@@ -21,7 +21,9 @@ use crate::{

config::Config,

global_state::GlobalStateSnapshot,

line_index::{LineEndings, LineIndex, OffsetEncoding},

- lsp_ext, semantic_tokens, Result,

+ lsp_ext,

+ lsp_utils::invalid_params_error,

+ semantic_tokens, Result,

};

pub(crate) fn position(line_index: &LineIndex, offset: TextSize) -> lsp_types::Position {

@@ -1198,7 +1200,9 @@ pub(crate) fn markup_content(markup: Markup) -> lsp_types::MarkupContent {

}

pub(crate) fn rename_error(err: RenameError) -> crate::LspError {

- crate::LspError { code: lsp_server::ErrorCode::InvalidParams as i32, message: err.to_string() }

+ // This is wrong, but we don't have a better alternative I suppose?

+ // https://github.com/microsoft/language-server-protocol/issues/1341

+ invalid_params_error(err.to_string())

}

#[cfg(test)]

diff --git a/docs/dev/style.md b/docs/dev/style.md
index 6131cdcbdc..92e79508b6 100644
--- a/docs/dev/style.md
+++ b/docs/dev/style.md

@@ -895,6 +895,29 @@ fn foo() -> Option<Bar> {

**Rationale:** reduce cognitive stack usage.

+Use `return Err(err)` to throw an error:

+```rust

+// GOOD

+fn f() -> Result<(), ()> {

+ if condition {

+ return Err(());

+ }

+ Ok(())

+// BAD

+fn f() -> Result<(), ()> {

+ if condition {

+ Err(())?;

+ }

+ Ok(())

+```

+**Rationale:** `return` has type `!`, which allows the compiler to flag dead

+code (`Err(...)?` is of unconstrained generic type `T`).

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