Extract lint scopes from `cargo watch`

Currently all of our VS Code diagnostics are given the source of
`rustc`. However, if you have something like `cargo-watch.command` set
to `clippy` it will also watch for Clippy lints. The `rustc` source is a
bit misleading in that case.

Fortunately, Rust's tool lints (RFC 2103) line up perfectly with VS
Code's concept of `source`. This checks for lints scoped to a given tool
and then splits them in to a `source` and tool-specific `code`.

1 files changed, 12 insertions, 2 deletions

diff --git a/editors/code/src/utils/rust_diagnostics.ts b/editors/code/src/utils/rust_diagnostics.ts
index ed049c95e..3c524cb37 100644
--- a/editors/code/src/utils/rust_diagnostics.ts
+++ b/editors/code/src/utils/rust_diagnostics.ts
@@ -187,8 +187,18 @@ export function mapRustDiagnosticToVsCode(
 
     const vd = new vscode.Diagnostic(location.range, rd.message, severity);
 
-    vd.source = 'rustc';
-    vd.code = rd.code ? rd.code.code : undefined;
+    let source = 'rustc';
+    let code = rd.code && rd.code.code;
+    if (code) {
+        // See if this is an RFC #2103 scoped lint (e.g. from Clippy)
+        const scopedCode = code.split('::');
+        if (scopedCode.length === 2) {
+            [source, code] = scopedCode;
+        }
+    }
+
+    vd.source = source;
+    vd.code = code;
     vd.relatedInformation = [];
 
     for (const secondarySpan of secondarySpans) {