minor

src/sql-parser/src/ast/defs/statement.rs

@@ -3210,9 +3210,7 @@ pub struct RefreshAtOptionValue<T: AstInfo> {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
 pub struct RefreshEveryOptionValue<T: AstInfo> {
-    // The following is a String and not an IntervalValue, because that starts with the keyword
-    // INTERVAL, but that is not needed here, since the only thing that can come here is an
-    // interval, so no need to indicate this with an extra keyword.
+    // The refresh interval.
     pub interval: IntervalValue,
     // We need an Expr because we want to support `mz_now()`.
     pub aligned_to: Option<Expr<T>>,

src/sql/src/plan/with_options.rs

@@ -437,6 +437,7 @@ impl<V: TryFromValue<Value>, T: AstInfo + std::fmt::Debug> TryFromValue<WithOpti
             | WithOptionValue::Refresh(_) => sql_bail!(
                 "incompatible value types: cannot convert {} to {}",
                 match v {
+                    // The first few are unreachable because they are handled at the top of the outer match.
                     WithOptionValue::Value(_) => unreachable!(),
                     WithOptionValue::Ident(_) => unreachable!(),
                     WithOptionValue::RetainHistoryFor(_) => unreachable!(),

src/sql/src/pure.rs

@@ -1488,6 +1488,9 @@ const MZ_NOW_SCHEMA: &str = "mz_catalog";
 
 /// Purifies a CREATE MATERIALIZED VIEW statement. Additionally, it adjusts `resolved_ids` if
 /// references to ids appear or disappear during the purification.
+///
+/// Note that in contrast with [`purify_statement`], this doesn't need to be async, because
+/// this function is not making any network calls.
 pub fn purify_create_materialized_view_options(
     catalog: impl SessionCatalog,
     mz_now: Option<Timestamp>,