Document the options

oli-obk · oli-obk · commit 26ffca25271f · 2022-12-12T15:22:58.000Z
diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
@@ -30,6 +30,9 @@ use std::sync::Arc;
 /// [`take`]: Self::take
 /// [`compute`]: Self::compute
 pub struct Query<T> {
+    // The outer option is `None` until the query is computed.
+    // Then the whole thing becomes `Some(Some(result))`.
+    // Once the value gets taken/stolen, it is `Some(None)`.
     result: RefCell<Option<Option<Result<T>>>>,
 }
 

Original file line number	Diff line number	Diff line change
`@@ -30,6 +30,9 @@ use std::sync::Arc;`
`30`	`30`	/// [`take`]: Self::take
`31`	`31`	/// [`compute`]: Self::compute
`32`	`32`	`pub struct Query<T> {`
	`33`	+ // The outer option is `None` until the query is computed.
	`34`	+ // Then the whole thing becomes `Some(Some(result))`.
	`35`	+ // Once the value gets taken/stolen, it is `Some(None)`.
`33`	`36`	`result: RefCell<Option<Option<Result<T>>>>,`
`34`	`37`	`}`
`35`	`38`