diff --git a/edb/pgsql/common.py b/edb/pgsql/common.py
index 38d1b88fe3e..9e991297318 100644
--- a/edb/pgsql/common.py
+++ b/edb/pgsql/common.py
@@ -192,6 +192,12 @@ def versioned_name(
         return s
 
 
+def maybe_versioned_name(
+    s: tuple[str, ...], *, versioned: bool,
+) -> tuple[str, ...]:
+    return versioned_name(s) if versioned else s
+
+
 @functools.lru_cache()
 def _edgedb_name_to_pg_name(name: str, prefix_length: int = 0) -> str:
     # Note: PostgreSQL doesn't have a sha1 implementation as a
diff --git a/edb/pgsql/compiler/expr.py b/edb/pgsql/compiler/expr.py
index d16e7a859c0..3525c2d0855 100644
--- a/edb/pgsql/compiler/expr.py
+++ b/edb/pgsql/compiler/expr.py
@@ -497,12 +497,19 @@ def compile_operator(
 
     else:
         if expr.sql_function:
-            sql_func = expr.sql_function[0]
-            func_name = tuple(sql_func.split('.', 1))
-            if len(expr.sql_function) > 1:
+            sql_func, *cast_types = expr.sql_function
+
+            func_name = common.maybe_versioned_name(
+                tuple(sql_func.split('.', 1)),
+                versioned=(
+                    ctx.env.versioned_stdlib
+                    and expr.func_shortname.get_root_module_name().name != 'ext'
+                ),
+            )
+
+            if cast_types:
                 # Explicit operand types given in FROM SQL FUNCTION
-                lexpr, rexpr = _cast_operands(
-                    lexpr, rexpr, expr.sql_function[1:])
+                lexpr, rexpr = _cast_operands(lexpr, rexpr, cast_types)
         else:
             func_name = common.get_operator_backend_name(
                 expr.func_shortname, aspect='function',
@@ -541,7 +548,7 @@ def compile_operator(
 def _cast_operands(
     lexpr: Optional[pgast.BaseExpr],
     rexpr: Optional[pgast.BaseExpr],
-    sql_types: Tuple[str, ...],
+    sql_types: Sequence[str],
 ) -> Tuple[Optional[pgast.BaseExpr], Optional[pgast.BaseExpr]]:
 
     if lexpr is not None:
@@ -584,6 +591,27 @@ def _cast_operands(
     return lexpr, rexpr
 
 
+def get_func_call_backend_name(
+    expr: irast.FunctionCall, *,
+    ctx: context.CompilerContextLevel
+) -> Tuple[str, ...]:
+    if expr.func_sql_function:
+        # The name might contain a "." if it's one of our
+        # metaschema helpers.
+        func_name = common.maybe_versioned_name(
+            tuple(expr.func_sql_function.split('.', 1)),
+            versioned=(
+                ctx.env.versioned_stdlib
+                and expr.func_shortname.get_root_module_name().name != 'ext'
+            ),
+        )
+    else:
+        func_name = common.get_function_backend_name(
+            expr.func_shortname, expr.backend_name,
+            versioned=ctx.env.versioned_stdlib)
+    return func_name
+
+
 @dispatch.compile.register(irast.TypeCheckOp)
 def compile_TypeCheckOp(
         expr: irast.TypeCheckOp, *,
@@ -717,7 +745,7 @@ def compile_FunctionCall(
 
         args.append(pgast.VariadicArgument(expr=var))
 
-    name = relgen.get_func_call_backend_name(expr, ctx=ctx)
+    name = get_func_call_backend_name(expr, ctx=ctx)
 
     result: pgast.BaseExpr = pgast.FuncCall(name=name, args=args)
 
diff --git a/edb/pgsql/compiler/relgen.py b/edb/pgsql/compiler/relgen.py
index c3ccee95ec5..8033d8c8438 100644
--- a/edb/pgsql/compiler/relgen.py
+++ b/edb/pgsql/compiler/relgen.py
@@ -3304,21 +3304,6 @@ def _compile_call_args(
     return args
 
 
-def get_func_call_backend_name(
-        expr: irast.FunctionCall, *,
-        ctx: context.CompilerContextLevel) -> Tuple[str, ...]:
-    if expr.func_sql_function:
-        # The name might contain a "." if it's one of our
-        # metaschema helpers.
-        # XXX: VERSIONING?
-        func_name = tuple(expr.func_sql_function.split('.', 1))
-    else:
-        func_name = common.get_function_backend_name(
-            expr.func_shortname, expr.backend_name,
-            versioned=ctx.env.versioned_stdlib)
-    return func_name
-
-
 def process_set_as_func_enumerate(
     ir_set: irast.Set, *, ctx: context.CompilerContextLevel
 ) -> SetRVars:
@@ -3333,7 +3318,7 @@ def process_set_as_func_enumerate(
         with newctx.new() as newctx2:
             newctx2.expr_exposed = False
             args = _compile_call_args(inner_func_set, ctx=newctx2)
-        func_name = get_func_call_backend_name(inner_func, ctx=newctx)
+        func_name = exprcomp.get_func_call_backend_name(inner_func, ctx=newctx)
 
         set_expr = _process_set_func_with_ordinality(
             ir_set=inner_func_set,
@@ -3362,7 +3347,7 @@ def process_set_as_func_expr(
         if expr.body is not None:
             set_expr = dispatch.compile(expr.body, ctx=newctx)
         else:
-            name = get_func_call_backend_name(expr, ctx=newctx)
+            name = exprcomp.get_func_call_backend_name(expr, ctx=newctx)
 
             if expr.typemod is qltypes.TypeModifier.SetOfType:
                 set_expr = _process_set_func(
@@ -3539,7 +3524,7 @@ def process_set_as_agg_expr_inner(
 
                 args.append(arg_ref)
 
-        name = get_func_call_backend_name(expr, ctx=newctx)
+        name = exprcomp.get_func_call_backend_name(expr, ctx=newctx)
 
         set_expr = pgast.FuncCall(
             name=name, args=args, agg_order=agg_sort, agg_filter=agg_filter,