diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 233b7b1cc9..df766cdec1 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -3583,6 +3583,7 @@ coerceJsonFuncExpr(ParseState *pstate, Node *expr,
 	Node	   *res;
 	int			location;
 	Oid			exprtype = exprType(expr);
+	int32		baseTypmod = returning->typmod;
 
 	/* if output type is not specified or equals to function type, return */
 	if (!OidIsValid(returning->typid) || returning->typid == exprtype)
@@ -3611,10 +3612,19 @@ coerceJsonFuncExpr(ParseState *pstate, Node *expr,
 		return (Node *) fexpr;
 	}
 
+	/*
+	 * For domains, consider the base type's typmod to decide whether to setup
+	 * an implicit or explicit cast.
+	 */
+	if (get_typtype(returning->typid) == TYPTYPE_DOMAIN)
+		(void) getBaseTypeAndTypmod(returning->typid, &baseTypmod);
+
 	/* try to coerce expression to the output type */
 	res = coerce_to_target_type(pstate, expr, exprtype,
-								returning->typid, returning->typmod,
+								returning->typid, baseTypmod,
+								baseTypmod > 0 ? COERCION_IMPLICIT :
 								COERCION_EXPLICIT,
+								baseTypmod > 0 ? COERCE_IMPLICIT_CAST :
 								COERCE_EXPLICIT_CAST,
 								location);
 
@@ -3640,6 +3650,7 @@ makeJsonConstructorExpr(ParseState *pstate, JsonConstructorType type,
 	JsonConstructorExpr *jsctor = makeNode(JsonConstructorExpr);
 	Node	   *placeholder;
 	Node	   *coercion;
+	int32		baseTypmod = returning->typmod;
 
 	jsctor->args = args;
 	jsctor->func = fexpr;
@@ -3677,6 +3688,17 @@ makeJsonConstructorExpr(ParseState *pstate, JsonConstructorType type,
 		placeholder = (Node *) cte;
 	}
 
+	/*
+	 * Convert the source expression to text, because coerceJsonFuncExpr()
+	 * will create an implicit cast to the RETURNING types with typmod and
+	 * there are no implicit casts from json(b) to such types.  For domains,
+	 * the base type's typmod will be considered, so do so here too.
+	 */
+	if (get_typtype(returning->typid) == TYPTYPE_DOMAIN)
+		(void) getBaseTypeAndTypmod(returning->typid, &baseTypmod);
+	if (baseTypmod > 0)
+		placeholder = coerce_to_specific_type(pstate, placeholder, TEXTOID,
+											  "JSON_CONSTRUCTOR()");
 	coercion = coerceJsonFuncExpr(pstate, placeholder, returning, true);
 
 	if (coercion != placeholder)
diff --git a/src/test/regress/expected/sqljson.out b/src/test/regress/expected/sqljson.out
index cbf8542d8d..4f91e2117e 100644
--- a/src/test/regress/expected/sqljson.out
+++ b/src/test/regress/expected/sqljson.out
@@ -1278,3 +1278,20 @@ CREATE OR REPLACE VIEW public.is_json_view AS
     '{}'::text IS JSON OBJECT WITH UNIQUE KEYS AS object
    FROM generate_series(1, 3) i(i)
 DROP VIEW is_json_view;
+-- Test implicit coercion to a fixed-length type specified in RETURNING
+SELECT JSON_SERIALIZE('{ "a" : 1 } ' RETURNING varchar(2));
+ERROR:  value too long for type character varying(2)
+SELECT JSON_OBJECT('a': JSON_OBJECT('b': 1 RETURNING varchar(2)));
+ERROR:  value too long for type character varying(2)
+SELECT JSON_ARRAY(JSON_ARRAY('{ "a" : 123 }' RETURNING varchar(2)));
+ERROR:  value too long for type character varying(2)
+SELECT JSON_ARRAYAGG(('111' || i)::bytea FORMAT JSON NULL ON NULL RETURNING varchar(2)) FROM generate_series(1,1) i;
+ERROR:  value too long for type character varying(2)
+SELECT JSON_OBJECTAGG(i: ('111' || i)::bytea FORMAT JSON WITH UNIQUE RETURNING varchar(2)) FROM generate_series(1, 1) i;
+ERROR:  value too long for type character varying(2)
+-- Now try domain over fixed-length type
+CREATE DOMAIN sqljson_char2 AS char(2) CHECK (VALUE NOT IN ('12'));
+SELECT JSON_SERIALIZE('123' RETURNING sqljson_char2);
+ERROR:  value too long for type character(2)
+SELECT JSON_SERIALIZE('12' RETURNING sqljson_char2);
+ERROR:  value for domain sqljson_char2 violates check constraint "sqljson_char2_check"
diff --git a/src/test/regress/sql/sqljson.sql b/src/test/regress/sql/sqljson.sql
index e6e20175b0..bb2487e864 100644
--- a/src/test/regress/sql/sqljson.sql
+++ b/src/test/regress/sql/sqljson.sql
@@ -463,3 +463,15 @@ SELECT '1' IS JSON AS "any", ('1' || i) IS JSON SCALAR AS "scalar", '[]' IS NOT
 \sv is_json_view
 
 DROP VIEW is_json_view;
+
+-- Test implicit coercion to a fixed-length type specified in RETURNING
+SELECT JSON_SERIALIZE('{ "a" : 1 } ' RETURNING varchar(2));
+SELECT JSON_OBJECT('a': JSON_OBJECT('b': 1 RETURNING varchar(2)));
+SELECT JSON_ARRAY(JSON_ARRAY('{ "a" : 123 }' RETURNING varchar(2)));
+SELECT JSON_ARRAYAGG(('111' || i)::bytea FORMAT JSON NULL ON NULL RETURNING varchar(2)) FROM generate_series(1,1) i;
+SELECT JSON_OBJECTAGG(i: ('111' || i)::bytea FORMAT JSON WITH UNIQUE RETURNING varchar(2)) FROM generate_series(1, 1) i;
+
+-- Now try domain over fixed-length type
+CREATE DOMAIN sqljson_char2 AS char(2) CHECK (VALUE NOT IN ('12'));
+SELECT JSON_SERIALIZE('123' RETURNING sqljson_char2);
+SELECT JSON_SERIALIZE('12' RETURNING sqljson_char2);