From d190e69e18a73e15b3a7f49973d3c1c7e812b237 Mon Sep 17 00:00:00 2001
From: LucaCappelletti94 <cappelletti.luca94@gmail.com>
Date: Wed, 11 Nov 2026 22:45:53 +0100
Subject: [PATCH] PostgreSQL: Support `CONVERSION` members in `ALTER EXTENSION`

---
 fuzz/fuzz_seeds/postgres_alter_extension.sql | 1 +
 src/ast/ddl.rs                               | 3 +++
 src/keywords.rs                              | 1 +
 src/parser/mod.rs                            | 4 ++++
 tests/sqlparser_postgres.rs                  | 2 ++
 5 files changed, 11 insertions(+)

diff --git a/fuzz/fuzz_seeds/postgres_alter_extension.sql b/fuzz/fuzz_seeds/postgres_alter_extension.sql
index 7c3d0680ce..867a079c74 100644
--- a/fuzz/fuzz_seeds/postgres_alter_extension.sql
+++ b/fuzz/fuzz_seeds/postgres_alter_extension.sql
@@ -13,3 +13,4 @@ ALTER EXTENSION citext DROP EVENT TRIGGER trg;
 ALTER EXTENSION citext ADD FOREIGN DATA WRAPPER fdw;
 ALTER EXTENSION citext DROP SERVER srv;
 ALTER EXTENSION citext ADD COLLATION public.coll;
+ALTER EXTENSION citext DROP CONVERSION public.conv;
diff --git a/src/ast/ddl.rs b/src/ast/ddl.rs
index 9ca7ed2ffe..8c7bd76c0d 100644
--- a/src/ast/ddl.rs
+++ b/src/ast/ddl.rs
@@ -4930,6 +4930,8 @@ pub enum AlterExtensionMember {
     AccessMethod(Ident),
     /// `COLLATION object_name`
     Collation(ObjectName),
+    /// `CONVERSION object_name`
+    Conversion(ObjectName),
     /// `EVENT TRIGGER object_name`
     EventTrigger(Ident),
     /// `FOREIGN DATA WRAPPER object_name`
@@ -4981,6 +4983,7 @@ impl fmt::Display for AlterExtensionMember {
         match self {
             AlterExtensionMember::AccessMethod(name) => write!(f, "ACCESS METHOD {name}"),
             AlterExtensionMember::Collation(name) => write!(f, "COLLATION {name}"),
+            AlterExtensionMember::Conversion(name) => write!(f, "CONVERSION {name}"),
             AlterExtensionMember::EventTrigger(name) => write!(f, "EVENT TRIGGER {name}"),
             AlterExtensionMember::ForeignDataWrapper(name) => {
                 write!(f, "FOREIGN DATA WRAPPER {name}")
diff --git a/src/keywords.rs b/src/keywords.rs
index f6b0c1deee..6ed7eb6014 100644
--- a/src/keywords.rs
+++ b/src/keywords.rs
@@ -264,6 +264,7 @@ define_keywords!(
     CONTACT,
     CONTAINS,
     CONTINUE,
+    CONVERSION,
     CONVERT,
     COPY,
     COPY_OPTIONS,
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index ff67abc641..c75111f887 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -12545,6 +12545,10 @@ impl<'a> Parser<'a> {
             Ok(AlterExtensionMember::Collation(
                 self.parse_object_name(false)?,
             ))
+        } else if self.parse_keyword(Keyword::CONVERSION) {
+            Ok(AlterExtensionMember::Conversion(
+                self.parse_object_name(false)?,
+            ))
         } else if self.parse_keywords(&[Keyword::EVENT, Keyword::TRIGGER]) {
             Ok(AlterExtensionMember::EventTrigger(self.parse_identifier()?))
         } else if self.parse_keywords(&[Keyword::FOREIGN, Keyword::DATA, Keyword::WRAPPER]) {
diff --git a/tests/sqlparser_postgres.rs b/tests/sqlparser_postgres.rs
index 2a5db79891..bdcc35c0b0 100644
--- a/tests/sqlparser_postgres.rs
+++ b/tests/sqlparser_postgres.rs
@@ -13531,6 +13531,7 @@ fn alter_extension_member_round_trip_forms(action: &str) {
         format!("ALTER EXTENSION ext_name {action} ACCESS METHOD btree"),
         format!("ALTER EXTENSION ext_name {action} COLLATION en_US"),
         format!("ALTER EXTENSION ext_name {action} COLLATION schema.en_US"),
+        format!("ALTER EXTENSION ext_name {action} CONVERSION conv"),
         format!("ALTER EXTENSION ext_name {action} EVENT TRIGGER trg"),
         format!("ALTER EXTENSION ext_name {action} FOREIGN DATA WRAPPER fdw"),
         format!("ALTER EXTENSION ext_name {action} FOREIGN TABLE ft"),
@@ -13721,6 +13722,7 @@ fn parse_alter_extension_add_member() {
     for member in [
         "ACCESS METHOD",
         "COLLATION",
+        "CONVERSION",
         "EVENT TRIGGER",
         "FOREIGN DATA WRAPPER",
         "FOREIGN TABLE",