diff --git a/src/backend/optimizer/util/clauses.c b/src/backend/optimizer/util/clauses.c
index 19b5cf7b612a2f8d3d79abf5cca90dc19baa5722..fb1d070500cc790807e72bff338941452c7c9850 100644
--- a/src/backend/optimizer/util/clauses.c
+++ b/src/backend/optimizer/util/clauses.c
@@ -3196,10 +3196,19 @@ eval_const_expressions_mutator(Node *node,
 				 * But it can arise while simplifying functions.)  Also, we
 				 * can optimize field selection from a RowExpr construct.
 				 *
-				 * We must however check that the declared type of the field
-				 * is still the same as when the FieldSelect was created ---
-				 * this can change if someone did ALTER COLUMN TYPE on the
-				 * rowtype.
+				 * However, replacing a whole-row Var in this way has a
+				 * pitfall: if we've already built the reltargetlist for the
+				 * source relation, then the whole-row Var is scheduled to be
+				 * produced by the relation scan, but the simple Var probably
+				 * isn't, which will lead to a failure in setrefs.c.  This is
+				 * not a problem when handling simple single-level queries, in
+				 * which expression simplification always happens first.  It
+				 * is a risk for lateral references from subqueries, though.
+				 * To avoid such failures, don't optimize uplevel references.
+				 *
+				 * We must also check that the declared type of the field is
+				 * still the same as when the FieldSelect was created --- this
+				 * can change if someone did ALTER COLUMN TYPE on the rowtype.
 				 */
 				FieldSelect *fselect = (FieldSelect *) node;
 				FieldSelect *newfselect;
@@ -3208,7 +3217,8 @@ eval_const_expressions_mutator(Node *node,
 				arg = eval_const_expressions_mutator((Node *) fselect->arg,
 													 context);
 				if (arg && IsA(arg, Var) &&
-					((Var *) arg)->varattno == InvalidAttrNumber)
+					((Var *) arg)->varattno == InvalidAttrNumber &&
+					((Var *) arg)->varlevelsup == 0)
 				{
 					if (rowtype_field_matches(((Var *) arg)->vartype,
 											  fselect->fieldnum,
diff --git a/src/test/regress/expected/rangefuncs.out b/src/test/regress/expected/rangefuncs.out
index 774e75e2ac4f613125485a7af8470d88a3746e24..7991e993f1477d48b2bcebeb27a0a8821752b816 100644
--- a/src/test/regress/expected/rangefuncs.out
+++ b/src/test/regress/expected/rangefuncs.out
@@ -2006,3 +2006,55 @@ FROM
   3 | FROM 10000000876 | from 10000000876
 (3 rows)
 
+-- check whole-row-Var handling in nested lateral functions (bug #11703)
+create function extractq2(t int8_tbl) returns int8 as $$
+  select t.q2
+$$ language sql immutable;
+explain (verbose, costs off)
+select x from int8_tbl, extractq2(int8_tbl) f(x);
+                QUERY PLAN                
+------------------------------------------
+ Nested Loop
+   Output: f.x
+   ->  Seq Scan on public.int8_tbl
+         Output: int8_tbl.q1, int8_tbl.q2
+   ->  Function Scan on f
+         Output: f.x
+         Function Call: int8_tbl.q2
+(7 rows)
+
+select x from int8_tbl, extractq2(int8_tbl) f(x);
+         x         
+-------------------
+               456
+  4567890123456789
+               123
+  4567890123456789
+ -4567890123456789
+(5 rows)
+
+create function extractq2_2(t int8_tbl) returns table(ret1 int8) as $$
+  select extractq2(t)
+$$ language sql immutable;
+explain (verbose, costs off)
+select x from int8_tbl, extractq2_2(int8_tbl) f(x);
+            QUERY PLAN             
+-----------------------------------
+ Nested Loop
+   Output: ((int8_tbl.*).q2)
+   ->  Seq Scan on public.int8_tbl
+         Output: int8_tbl.*
+   ->  Result
+         Output: (int8_tbl.*).q2
+(6 rows)
+
+select x from int8_tbl, extractq2_2(int8_tbl) f(x);
+         x         
+-------------------
+               456
+  4567890123456789
+               123
+  4567890123456789
+ -4567890123456789
+(5 rows)
+
diff --git a/src/test/regress/sql/rangefuncs.sql b/src/test/regress/sql/rangefuncs.sql
index 07d2e1a490e6636882ff6db5a8e09861b13a2400..470571b0fb6362bad966ecd8e46afcc956f5cf8b 100644
--- a/src/test/regress/sql/rangefuncs.sql
+++ b/src/test/regress/sql/rangefuncs.sql
@@ -608,3 +608,23 @@ SELECT *,
         END)
 FROM
   (VALUES (1,''), (2,'0000000049404'), (3,'FROM 10000000876')) v(id, str);
+
+-- check whole-row-Var handling in nested lateral functions (bug #11703)
+
+create function extractq2(t int8_tbl) returns int8 as $$
+  select t.q2
+$$ language sql immutable;
+
+explain (verbose, costs off)
+select x from int8_tbl, extractq2(int8_tbl) f(x);
+
+select x from int8_tbl, extractq2(int8_tbl) f(x);
+
+create function extractq2_2(t int8_tbl) returns table(ret1 int8) as $$
+  select extractq2(t)
+$$ language sql immutable;
+
+explain (verbose, costs off)
+select x from int8_tbl, extractq2_2(int8_tbl) f(x);
+
+select x from int8_tbl, extractq2_2(int8_tbl) f(x);