add short paragraph on macro use case for mismatched bindings

max-niederman · max-niederman · commit 3ec08d46f307 · 2024-08-22T14:19:46.000-07:00
diff --git a/text/3637-guard-patterns.md b/text/3637-guard-patterns.md
@@ -334,6 +334,10 @@ match Some(0) {
 }
 ```
 
+This is also very useful for macros, because it allows
+1. pattern macros to use guard patterns freely without introducing new bindings the user has to be aware of in order to use the pattern macro within a disjunction, and
+2. macro users to pass guard patterns to macros freely, even if the macro uses the pattern within a disjunction.
+
 As mentioned above, this case is not covered by this RFC, because `x` would need to be bound in both cases of the disjunction.
 
 However, we could support this by automatically detecting that `x` is not ever used outside of the guard pattern, and allowing the guard to capture the binding, so it wouldn't have to be bound in other cases of the disjunction.

Original file line number	Diff line number	Diff line change
`@@ -334,6 +334,10 @@ match Some(0) {`
`334`	`334`	`}`
`335`	`335`	```
`336`	`336`
	`337`	`+This is also very useful for macros, because it allows`
	`338`	`+1. pattern macros to use guard patterns freely without introducing new bindings the user has to be aware of in order to use the pattern macro within a disjunction, and`
	`339`	`+2. macro users to pass guard patterns to macros freely, even if the macro uses the pattern within a disjunction.`
	`340`	`+`
`337`	`341`	As mentioned above, this case is not covered by this RFC, because `x` would need to be bound in both cases of the disjunction.
`338`	`342`
`339`	`343`	However, we could support this by automatically detecting that `x` is not ever used outside of the guard pattern, and allowing the guard to capture the binding, so it wouldn't have to be bound in other cases of the disjunction.