From 886218d972f1fd62a58682590c35ef6036f57bc9 Mon Sep 17 00:00:00 2001
From: "Sean T. Allen" <sean@seantallen.com>
Date: Sun, 1 Mar 2026 09:27:52 -0500
Subject: [PATCH] Add \exhaustive\ annotation to exhaustive match blocks

Ponyc recently added an \exhaustive\ annotation for match expressions.
When present, the compiler will fail compilation if the match is not
exhaustive. This protects against future breakage if new variants are
added to a union type.
---
 examples/bytea/bytea-example.pony              |  4 ++--
 examples/cancel/cancel-example.pony            |  2 +-
 examples/copy-in/copy-in-example.pony          | 10 +++++-----
 examples/copy-out/copy-out-example.pony        |  6 +++---
 examples/crud/crud-example.pony                | 10 +++++-----
 .../listen-notify/listen-notify-example.pony   |  4 ++--
 .../named-prepared-query-example.pony          |  4 ++--
 examples/notice/notice-example.pony            |  2 +-
 .../parameter-status-example.pony              |  2 +-
 .../prepared-query/prepared-query-example.pony |  4 ++--
 examples/query/query-example.pony              |  4 ++--
 .../ssl-preferred-query-example.pony           |  4 ++--
 examples/ssl-query/ssl-query-example.pony      |  4 ++--
 examples/streaming/streaming-example.pony      |  6 +++---
 .../transaction-status-example.pony            |  6 +++---
 postgres/_authentication_failure_reason.pony   |  2 +-
 postgres/_cancel_sender.pony                   |  4 ++--
 postgres/_frontend_message.pony                |  2 +-
 postgres/_test_cancel.pony                     |  4 ++--
 postgres/_test_copy_out.pony                   |  2 +-
 postgres/_test_equality.pony                   |  2 +-
 postgres/_test_query.pony                      | 16 ++++++++--------
 postgres/_test_response_parser.pony            |  2 +-
 postgres/_test_session.pony                    |  2 +-
 postgres/_test_ssl.pony                        |  4 ++--
 postgres/_test_transaction_status.pony         |  2 +-
 postgres/postgres.pony                         |  4 ++--
 postgres/query_error.pony                      |  2 +-
 postgres/rows.pony                             |  2 +-
 postgres/session.pony                          | 18 +++++++++---------
 30 files changed, 70 insertions(+), 70 deletions(-)

diff --git a/examples/bytea/bytea-example.pony b/examples/bytea/bytea-example.pony
index c2dddaf..4339860 100644
--- a/examples/bytea/bytea-example.pony
+++ b/examples/bytea/bytea-example.pony
@@ -46,13 +46,13 @@ actor Client is (SessionStatusNotify & ResultReceiver)
     _out.print("Failed to authenticate.")
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       _out.print("ResultSet (" + r.rows().size().string() + " rows):")
       for row in r.rows().values() do
         for field in row.fields.values() do
           _out.write(field.name + "=")
-          match field.value
+          match \exhaustive\ field.value
           | let v: Array[U8] val =>
             _out.print(v.size().string() + " bytes")
             // Print each byte's decimal value
diff --git a/examples/cancel/cancel-example.pony b/examples/cancel/cancel-example.pony
index c4b2d4e..40811b1 100644
--- a/examples/cancel/cancel-example.pony
+++ b/examples/cancel/cancel-example.pony
@@ -48,7 +48,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let err: ErrorResponseMessage =>
       if err.code == "57014" then
         _out.print("Query was cancelled (SQLSTATE 57014).")
diff --git a/examples/copy-in/copy-in-example.pony b/examples/copy-in/copy-in-example.pony
index 84f4807..b20f6e9 100644
--- a/examples/copy-in/copy-in-example.pony
+++ b/examples/copy-in/copy-in-example.pony
@@ -73,7 +73,7 @@ actor Client is (SessionStatusNotify & ResultReceiver & CopyInReceiver)
   be pg_copy_failed(session: Session,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("COPY failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
@@ -85,7 +85,7 @@ actor Client is (SessionStatusNotify & ResultReceiver & CopyInReceiver)
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table dropped (or didn't exist). Create it.
       _out.print("Creating table...")
@@ -105,14 +105,14 @@ actor Client is (SessionStatusNotify & ResultReceiver & CopyInReceiver)
         "COPY copy_in_example (name, value) FROM STDIN", this)
     | 3 =>
       // SELECT done. Print results and drop table.
-      match result
+      match \exhaustive\ result
       | let r: ResultSet =>
         _out.print("ResultSet (" + r.rows().size().string() + " rows):")
         for row in r.rows().values() do
           _out.write(" ")
           for field in row.fields.values() do
             _out.write(" " + field.name + "=")
-            match field.value
+            match \exhaustive\ field.value
             | let v: String => _out.write(v)
             | let v: I32 => _out.write(v.string())
             | None => _out.write("NULL")
@@ -133,7 +133,7 @@ actor Client is (SessionStatusNotify & ResultReceiver & CopyInReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/examples/copy-out/copy-out-example.pony b/examples/copy-out/copy-out-example.pony
index 82cca7b..d6cd9f4 100644
--- a/examples/copy-out/copy-out-example.pony
+++ b/examples/copy-out/copy-out-example.pony
@@ -64,7 +64,7 @@ actor Client is (SessionStatusNotify & ResultReceiver & CopyOutReceiver)
   be pg_copy_failed(session: Session,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("COPY failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
@@ -76,7 +76,7 @@ actor Client is (SessionStatusNotify & ResultReceiver & CopyOutReceiver)
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table dropped (or didn't exist). Create it.
       _out.print("Creating table...")
@@ -111,7 +111,7 @@ actor Client is (SessionStatusNotify & ResultReceiver & CopyOutReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/examples/crud/crud-example.pony b/examples/crud/crud-example.pony
index 88a8c23..5337d96 100644
--- a/examples/crud/crud-example.pony
+++ b/examples/crud/crud-example.pony
@@ -48,7 +48,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table dropped (or didn't exist). Create it.
       _out.print("Creating table...")
@@ -89,14 +89,14 @@ actor Client is (SessionStatusNotify & ResultReceiver)
         this)
     | 5 =>
       // Select done. Print results and delete all rows.
-      match result
+      match \exhaustive\ result
       | let r: ResultSet =>
         _out.print("ResultSet (" + r.rows().size().string() + " rows):")
         for row in r.rows().values() do
           _out.write(" ")
           for field in row.fields.values() do
             _out.write(" " + field.name + "=")
-            match field.value
+            match \exhaustive\ field.value
             | let v: String => _out.write(v)
             | let v: I16 => _out.write(v.string())
             | let v: I32 => _out.write(v.string())
@@ -128,7 +128,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
     end
 
   fun _print_row_modifying(result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: RowModifying =>
       _out.print(r.command() + " " + r.impacted().string() + " rows")
     end
@@ -136,7 +136,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/examples/listen-notify/listen-notify-example.pony b/examples/listen-notify/listen-notify-example.pony
index 03ab143..a035198 100644
--- a/examples/listen-notify/listen-notify-example.pony
+++ b/examples/listen-notify/listen-notify-example.pony
@@ -50,7 +50,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // LISTEN done, send notification
       _out.print("Subscribed. Sending notification...")
@@ -69,7 +69,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/examples/named-prepared-query/named-prepared-query-example.pony b/examples/named-prepared-query/named-prepared-query-example.pony
index 2706acb..c19108a 100644
--- a/examples/named-prepared-query/named-prepared-query-example.pony
+++ b/examples/named-prepared-query/named-prepared-query-example.pony
@@ -59,13 +59,13 @@ actor Client is (SessionStatusNotify & ResultReceiver & PrepareReceiver)
     close()
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       _out.print("ResultSet (" + r.rows().size().string() + " rows):")
       for row in r.rows().values() do
         for field in row.fields.values() do
           _out.write("  " + field.name + "=")
-          match field.value
+          match \exhaustive\ field.value
           | let v: String => _out.print(v)
           | let v: I16 => _out.print(v.string())
           | let v: I32 => _out.print(v.string())
diff --git a/examples/notice/notice-example.pony b/examples/notice/notice-example.pony
index 9e00c1a..4f6ca8a 100644
--- a/examples/notice/notice-example.pony
+++ b/examples/notice/notice-example.pony
@@ -55,7 +55,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/examples/parameter-status/parameter-status-example.pony b/examples/parameter-status/parameter-status-example.pony
index 8e3201b..ab8a0da 100644
--- a/examples/parameter-status/parameter-status-example.pony
+++ b/examples/parameter-status/parameter-status-example.pony
@@ -52,7 +52,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/examples/prepared-query/prepared-query-example.pony b/examples/prepared-query/prepared-query-example.pony
index cc9f61e..8aabe30 100644
--- a/examples/prepared-query/prepared-query-example.pony
+++ b/examples/prepared-query/prepared-query-example.pony
@@ -44,13 +44,13 @@ actor Client is (SessionStatusNotify & ResultReceiver)
     _out.print("Failed to authenticate.")
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       _out.print("ResultSet (" + r.rows().size().string() + " rows):")
       for row in r.rows().values() do
         for field in row.fields.values() do
           _out.write("  " + field.name + "=")
-          match field.value
+          match \exhaustive\ field.value
           | let v: String => _out.print(v)
           | let v: I16 => _out.print(v.string())
           | let v: I32 => _out.print(v.string())
diff --git a/examples/query/query-example.pony b/examples/query/query-example.pony
index 4644c86..cd56415 100644
--- a/examples/query/query-example.pony
+++ b/examples/query/query-example.pony
@@ -39,13 +39,13 @@ actor Client is (SessionStatusNotify & ResultReceiver)
     _out.print("Failed to authenticate.")
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       _out.print("ResultSet (" + r.rows().size().string() + " rows):")
       for row in r.rows().values() do
         for field in row.fields.values() do
           _out.write(field.name + "=")
-          match field.value
+          match \exhaustive\ field.value
           | let v: String => _out.print(v)
           | let v: I16 => _out.print(v.string())
           | let v: I32 => _out.print(v.string())
diff --git a/examples/ssl-preferred-query/ssl-preferred-query-example.pony b/examples/ssl-preferred-query/ssl-preferred-query-example.pony
index cdfb196..4bc8e57 100644
--- a/examples/ssl-preferred-query/ssl-preferred-query-example.pony
+++ b/examples/ssl-preferred-query/ssl-preferred-query-example.pony
@@ -68,13 +68,13 @@ actor Client is (SessionStatusNotify & ResultReceiver)
     _out.print("Failed to authenticate.")
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       _out.print("ResultSet (" + r.rows().size().string() + " rows):")
       for row in r.rows().values() do
         for field in row.fields.values() do
           _out.write(field.name + "=")
-          match field.value
+          match \exhaustive\ field.value
           | let v: String => _out.print(v)
           | let v: I16 => _out.print(v.string())
           | let v: I32 => _out.print(v.string())
diff --git a/examples/ssl-query/ssl-query-example.pony b/examples/ssl-query/ssl-query-example.pony
index ef2409c..f8d2195 100644
--- a/examples/ssl-query/ssl-query-example.pony
+++ b/examples/ssl-query/ssl-query-example.pony
@@ -63,13 +63,13 @@ actor Client is (SessionStatusNotify & ResultReceiver)
     _out.print("Failed to authenticate.")
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       _out.print("ResultSet (" + r.rows().size().string() + " rows):")
       for row in r.rows().values() do
         for field in row.fields.values() do
           _out.write(field.name + "=")
-          match field.value
+          match \exhaustive\ field.value
           | let v: String => _out.print(v)
           | let v: I16 => _out.print(v.string())
           | let v: I32 => _out.print(v.string())
diff --git a/examples/streaming/streaming-example.pony b/examples/streaming/streaming-example.pony
index ff26a8e..c97bbc7 100644
--- a/examples/streaming/streaming-example.pony
+++ b/examples/streaming/streaming-example.pony
@@ -86,7 +86,7 @@ actor Client is
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
@@ -101,7 +101,7 @@ actor Client is
       _out.write("   ")
       for field in row.fields.values() do
         _out.write(" " + field.name + "=")
-        match field.value
+        match \exhaustive\ field.value
         | let v: String => _out.write(v)
         | let v: I32 => _out.write(v.string())
         | None => _out.write("NULL")
@@ -122,7 +122,7 @@ actor Client is
     query: (PreparedQuery | NamedPreparedQuery),
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Stream failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/examples/transaction-status/transaction-status-example.pony b/examples/transaction-status/transaction-status-example.pony
index 4110b2d..fe6edf6 100644
--- a/examples/transaction-status/transaction-status-example.pony
+++ b/examples/transaction-status/transaction-status-example.pony
@@ -41,7 +41,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
     _out.print("Failed to authenticate.")
 
   be pg_transaction_status(session: Session, status: TransactionStatus) =>
-    match status
+    match \exhaustive\ status
     | TransactionIdle => _out.print("Transaction status: idle")
     | TransactionInBlock => _out.print("Transaction status: in transaction")
     | TransactionFailed => _out.print("Transaction status: failed")
@@ -50,7 +50,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // BEGIN done. Commit to return to idle.
       _session.execute(SimpleQuery("COMMIT"), this)
@@ -63,7 +63,7 @@ actor Client is (SessionStatusNotify & ResultReceiver)
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _out.print("Query failed: [" + e.severity + "] " + e.code + ": "
         + e.message)
diff --git a/postgres/_authentication_failure_reason.pony b/postgres/_authentication_failure_reason.pony
index 9227b15..955ac67 100644
--- a/postgres/_authentication_failure_reason.pony
+++ b/postgres/_authentication_failure_reason.pony
@@ -18,7 +18,7 @@ primitive InvalidPassword
 
 primitive ServerVerificationFailed
   """
-  The server's SCRAM signature did not match the expected value. This may
+  The server's SCRAM signature did not match \exhaustive\ the expected value. This may
   indicate a man-in-the-middle attack or a misconfigured server.
   """
 
diff --git a/postgres/_cancel_sender.pony b/postgres/_cancel_sender.pony
index 908ee80..8f48832 100644
--- a/postgres/_cancel_sender.pony
+++ b/postgres/_cancel_sender.pony
@@ -32,7 +32,7 @@ actor _CancelSender is (lori.TCPConnectionActor & lori.ClientLifecycleEventRecei
     _tcp_connection
 
   fun ref _on_connected() =>
-    match _info.ssl_mode
+    match \exhaustive\ _info.ssl_mode
     | SSLDisabled =>
       _send_cancel_and_close()
     | let _: (SSLRequired | SSLPreferred) =>
@@ -52,7 +52,7 @@ actor _CancelSender is (lori.TCPConnectionActor & lori.ClientLifecycleEventRecei
           _tcp_connection.close()
           return
         end
-        match _tcp_connection.start_tls(ctx, _info.host)
+        match \exhaustive\ _tcp_connection.start_tls(ctx, _info.host)
         | None => None  // Handshake started, wait for _on_tls_ready
         | let _: lori.StartTLSError =>
           _tcp_connection.close()
diff --git a/postgres/_frontend_message.pony b/postgres/_frontend_message.pony
index 8694237..339711e 100644
--- a/postgres/_frontend_message.pony
+++ b/postgres/_frontend_message.pony
@@ -182,7 +182,7 @@ primitive _FrontendMessage
         end
         offset = offset + 2
         for p in params.values() do
-          match p
+          match \exhaustive\ p
           | let s: String =>
             ifdef bigendian then
               msg.update_u32(offset, s.size().u32())?
diff --git a/postgres/_test_cancel.pony b/postgres/_test_cancel.pony
index 4eb2de4..440d88e 100644
--- a/postgres/_test_cancel.pony
+++ b/postgres/_test_cancel.pony
@@ -317,7 +317,7 @@ actor \nodoc\ _SSLCancelTestServer
         // SSLRequest — respond 'S' and upgrade to TLS
         let response: Array[U8] val = ['S']
         _tcp_connection.send(response)
-        match _tcp_connection.start_tls(_sslctx)
+        match \exhaustive\ _tcp_connection.start_tls(_sslctx)
         | None => _ssl_started = true
         | let _: lori.StartTLSError =>
           _tcp_connection.close()
@@ -450,7 +450,7 @@ actor \nodoc\ _CancelPgSleepClient is
       return
     end
 
-    match failure
+    match \exhaustive\ failure
     | let err: ErrorResponseMessage =>
       if err.code == "57014" then
         _h.complete(true)
diff --git a/postgres/_test_copy_out.pony b/postgres/_test_copy_out.pony
index 35810b8..bd467d9 100644
--- a/postgres/_test_copy_out.pony
+++ b/postgres/_test_copy_out.pony
@@ -776,7 +776,7 @@ actor \nodoc\ _CopyOutExportTestClient is
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _h.fail("Query failed: " + e.code + ": " + e.message)
     | let e: ClientQueryError =>
diff --git a/postgres/_test_equality.pony b/postgres/_test_equality.pony
index 8667338..d35a7d3 100644
--- a/postgres/_test_equality.pony
+++ b/postgres/_test_equality.pony
@@ -5,7 +5,7 @@ use "pony_test"
 class \nodoc\ iso _TestFieldEqualityReflexive is UnitTest
   """
   Every FieldDataTypes variant produces a Field that is equal to itself.
-  Covers all 9 variants of the FieldDataTypes union to verify each match
+  Covers all 9 variants of the FieldDataTypes union to verify each match \exhaustive\
   branch in Field.eq.
   """
   fun name(): String => "Field/Equality/Reflexive"
diff --git a/postgres/_test_query.pony b/postgres/_test_query.pony
index 4d132b0..93ac040 100644
--- a/postgres/_test_query.pony
+++ b/postgres/_test_query.pony
@@ -290,7 +290,7 @@ actor \nodoc\ _NonExistentTableQueryReceiver is
       return
     end
 
-    match failure
+    match \exhaustive\ failure
     | let e: ErrorResponseMessage =>
       _h.assert_eq[String]("42P01", e.code)
       _h.complete(true)
@@ -415,7 +415,7 @@ actor \nodoc\ _AllSuccessQueryRunningClient is
   be pg_query_failed(session: Session, query: Query,
     failure: (ErrorResponseMessage | ClientQueryError))
   =>
-    let query_str = match query
+    let query_str = match \exhaustive\ query
     | let sq: SimpleQuery => sq.string
     | let pq: PreparedQuery => pq.string
     | let nq: NamedPreparedQuery => nq.name
@@ -598,7 +598,7 @@ actor \nodoc\ _MultiStatementMixedClient is
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table created, now send multi-statement query
       _session.execute(
@@ -799,7 +799,7 @@ actor \nodoc\ _PreparedQueryNullParamReceiver is
       return
     end
 
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       if r.rows().size() != 1 then
         _h.fail("Wrong number of result rows.")
@@ -944,7 +944,7 @@ actor \nodoc\ _PreparedQueryInsertAndDeleteClient is
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table created, insert with PreparedQuery
       _session.execute(
@@ -1882,7 +1882,7 @@ actor \nodoc\ _CopyInInsertClient is
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table created, start COPY
       _session.copy_in(
@@ -2000,7 +2000,7 @@ actor \nodoc\ _CopyInAbortRollbackClient is
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table created, start COPY
       _session.copy_in(
@@ -2107,7 +2107,7 @@ actor \nodoc\ _ByteaQueryReceiver is
     _h.complete(false)
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       try
         let field = r.rows()(0)?.fields(0)?
diff --git a/postgres/_test_response_parser.pony b/postgres/_test_response_parser.pony
index b72e835..c993700 100644
--- a/postgres/_test_response_parser.pony
+++ b/postgres/_test_response_parser.pony
@@ -956,7 +956,7 @@ class \nodoc\ val _IncomingDataRowTestMessage
     wb.u32_be(0)
     wb.u16_be(number_of_columns.u16())
     for column in columns.values() do
-      match column
+      match \exhaustive\ column
       | None =>
         wb.u32_be(-1)
         payload_size = payload_size + 4
diff --git a/postgres/_test_session.pony b/postgres/_test_session.pony
index 972feb2..3bea53b 100644
--- a/postgres/_test_session.pony
+++ b/postgres/_test_session.pony
@@ -703,7 +703,7 @@ actor \nodoc\ _ByteaTestClient is (SessionStatusNotify & ResultReceiver)
     _h.complete(false)
 
   be pg_query_result(session: Session, result: Result) =>
-    match result
+    match \exhaustive\ result
     | let r: ResultSet =>
       try
         let field = r.rows()(0)?.fields(0)?
diff --git a/postgres/_test_ssl.pony b/postgres/_test_ssl.pony
index d85614b..4cdbd62 100644
--- a/postgres/_test_ssl.pony
+++ b/postgres/_test_ssl.pony
@@ -341,7 +341,7 @@ actor \nodoc\ _SSLSuccessTestServer
         // Client sent SSLRequest — respond 'S' and upgrade to TLS
         let response: Array[U8] val = ['S']
         _tcp_connection.send(response)
-        match _tcp_connection.start_tls(_sslctx)
+        match \exhaustive\ _tcp_connection.start_tls(_sslctx)
         | None => _ssl_started = true
         | let _: lori.StartTLSError =>
           _tcp_connection.close()
@@ -1007,7 +1007,7 @@ actor \nodoc\ _SSLPreferredCancelTestServer
           // SSLRequest — respond 'S' and upgrade to TLS
           let response: Array[U8] val = ['S']
           _tcp_connection.send(response)
-          match _tcp_connection.start_tls(_sslctx)
+          match \exhaustive\ _tcp_connection.start_tls(_sslctx)
           | None => _ssl_started = true
           | let _: lori.StartTLSError =>
             _tcp_connection.close()
diff --git a/postgres/_test_transaction_status.pony b/postgres/_test_transaction_status.pony
index 01ad608..4b318bb 100644
--- a/postgres/_test_transaction_status.pony
+++ b/postgres/_test_transaction_status.pony
@@ -422,7 +422,7 @@ actor \nodoc\ _TransactionCommitClient is
   be pg_query_result(session: Session, result: Result) =>
     _phase = _phase + 1
 
-    match _phase
+    match \exhaustive\ _phase
     | 1 =>
       // Table created, BEGIN
       _session.execute(SimpleQuery("BEGIN"), this)
diff --git a/postgres/postgres.pony b/postgres/postgres.pony
index 3101012..5cb035f 100644
--- a/postgres/postgres.pony
+++ b/postgres/postgres.pony
@@ -131,11 +131,11 @@ Results arrive via `ResultReceiver`:
 
 ```pony
 be pg_query_result(session: Session, result: Result) =>
-  match result
+  match \exhaustive\ result
   | let rs: ResultSet =>
     for row in rs.rows().values() do
       for field in row.fields.values() do
-        match field.value
+        match \exhaustive\ field.value
         | let s: String => _env.out.print(field.name + ": " + s)
         | let i: I32 => _env.out.print(field.name + ": " + i.string())
         | let b: Bool => _env.out.print(field.name + ": " + b.string())
diff --git a/postgres/query_error.pony b/postgres/query_error.pony
index 41ac8e3..0634f03 100644
--- a/postgres/query_error.pony
+++ b/postgres/query_error.pony
@@ -30,6 +30,6 @@ primitive DataError is ClientQueryError
   """
   Error returned when the data that came back from a query is in a format that
   this library doesn't expect. This might indicate something like, the number
-  of columns across rows returned doesn't match or other "this should never
+  of columns across rows returned doesn't match \exhaustive\ or other "this should never
   happen" type of errors.
   """
diff --git a/postgres/rows.pony b/postgres/rows.pony
index 16b9911..2e9a12e 100644
--- a/postgres/rows.pony
+++ b/postgres/rows.pony
@@ -86,7 +86,7 @@ primitive _RowsBuilder
     Rows(consume rows)
 
   fun _field_to_type(field: (String | None), type_id: U32): FieldDataTypes ? =>
-    match field
+    match \exhaustive\ field
     | let f: String =>
       match type_id
       | 16 => f.at("t")
diff --git a/postgres/session.pony b/postgres/session.pony
index c3ad2c7..5b4524b 100644
--- a/postgres/session.pony
+++ b/postgres/session.pony
@@ -315,7 +315,7 @@ class ref _SessionSSLNegotiating
     try
       let response = data(0)?
       if response == 'S' then
-        match s._connection().start_tls(_ssl_ctx, _host)
+        match \exhaustive\ s._connection().start_tls(_ssl_ctx, _host)
         | None =>
           _handshake_started = true
         | let _: lori.StartTLSError =>
@@ -588,7 +588,7 @@ class ref _SessionSCRAMAuthenticating is (_ConnectedState & _NotAuthenticated)
         let sig_b64_iso = server_final.substring(2)
         let sig_b64: String val = consume sig_b64_iso
         let received_sig = Base64.decode[Array[U8] iso](sig_b64)?
-        match _expected_server_signature
+        match \exhaustive\ _expected_server_signature
         | let expected: Array[U8] val =>
           if not ConstantTimeCompare(expected, consume received_sig) then
             on_authentication_failed(s, ServerVerificationFailed)
@@ -844,7 +844,7 @@ class _SessionLoggedIn is _AuthenticatedState
     // double-notification, then drain the remaining queued items.
     query_state.drain_in_flight(s, this)
     for queue_item in query_queue.values() do
-      match queue_item
+      match \exhaustive\ queue_item
       | let qry: _QueuedQuery =>
         qry.receiver.pg_query_failed(s, qry.query, SessionClosed)
       | let prep: _QueuedPrepare =>
@@ -953,9 +953,9 @@ class _QueryReady is _QueryNoQueryInFlight
   fun ref try_run_query(s: Session ref, li: _SessionLoggedIn ref) =>
     try
       if li.query_queue.size() > 0 then
-        match li.query_queue(0)?
+        match \exhaustive\ li.query_queue(0)?
         | let qry: _QueuedQuery =>
-          match qry.query
+          match \exhaustive\ qry.query
           | let sq: SimpleQuery =>
             li.query_state = _SimpleQueryInFlight.create()
             s._connection().send(_FrontendMessage.query(sq.string))
@@ -1038,7 +1038,7 @@ class _QueryReady is _QueryNoQueryInFlight
           s._connection().send(_FrontendMessage.query(co.sql))
         | let sq: _QueuedStreamingQuery =>
           li.query_state = _StreamingQueryInFlight.create()
-          match sq.query
+          match \exhaustive\ sq.query
           | let pq: PreparedQuery =>
             let parse = _FrontendMessage.parse("", pq.string,
               recover val Array[U32] end)
@@ -1134,7 +1134,7 @@ class _SimpleQueryInFlight is _QueryState
         end
         let rd = _row_description = None
 
-        match rd
+        match \exhaustive\ rd
         | let desc: Array[(String, U32)] val =>
           try
             let rows_object = _RowsBuilder(consume rows, desc)?
@@ -1289,7 +1289,7 @@ class _ExtendedQueryInFlight is _QueryState
         end
         let rd = _row_description = None
 
-        match rd
+        match \exhaustive\ rd
         | let desc: Array[(String, U32)] val =>
           try
             let rows_object = _RowsBuilder(consume rows, desc)?
@@ -2206,7 +2206,7 @@ trait _ConnectableState is _UnconnectedState
   An unopened session that can be connected to a server.
   """
   fun on_connected(s: Session ref) =>
-    match ssl_mode()
+    match \exhaustive\ ssl_mode()
     | SSLDisabled =>
       s.state = _SessionConnected(notify(), database_connect_info())
       notify().pg_session_connected(s)