1 files changed, 28 insertions, 4 deletions

diff --git a/editors/code/src/util.ts b/editors/code/src/util.ts
index 127a9e911..fe3fb71cd 100644
--- a/editors/code/src/util.ts
+++ b/editors/code/src/util.ts
@@ -74,10 +74,11 @@ export type RustDocument = vscode.TextDocument & { languageId: "rust" };
 export type RustEditor = vscode.TextEditor & { document: RustDocument };
 
 export function isRustDocument(document: vscode.TextDocument): document is RustDocument {
-    return document.languageId === 'rust'
-        // SCM diff views have the same URI as the on-disk document but not the same content
-        && document.uri.scheme !== 'git'
-        && document.uri.scheme !== 'svn';
+    // Prevent corrupted text (particularly via inlay hints) in diff views
+    // by allowing only `file` schemes
+    // unfortunately extensions that use diff views not always set this
+    // to something different than 'file' (see ongoing bug: #4608)
+    return document.languageId === 'rust' && document.uri.scheme === 'file';
 }
 
 export function isRustEditor(editor: vscode.TextEditor): editor is RustEditor {
@@ -93,3 +94,26 @@ export function isValidExecutable(path: string): boolean {
 
     return res.status === 0;
 }
+
+/** Sets ['when'](https://code.visualstudio.com/docs/getstarted/keybindings#_when-clause-contexts) clause contexts */
+export function setContextValue(key: string, value: any): Thenable<void> {
+    return vscode.commands.executeCommand('setContext', key, value);
+}
+
+/**
+ * Returns a higher-order function that caches the results of invoking the
+ * underlying function.
+ */
+export function memoize<Ret, TThis, Param extends string>(func: (this: TThis, arg: Param) => Ret) {
+    const cache = new Map<string, Ret>();
+
+    return function(this: TThis, arg: Param) {
+        const cached = cache.get(arg);
+        if (cached) return cached;
+
+        const result = func.call(this, arg);
+        cache.set(arg, result);
+
+        return result;
+    };
+}