Merge pull request cockroachdb#63580 from the-ericwang35/backport20.2…

…-63103

release-20.2: sql: wrap CastExpr within IndirectionExpr in a ParenExpr

pkg/sql/logictest/testdata/logic_test/enums

@@ -1179,3 +1179,42 @@ query T
 SELECT _enum FROM t58889 WHERE _enum::greeting58889 IN (NULL, 'hi':::greeting58889);
 ----
 hi
+
+
+subtest enum_array_cast
+
+statement ok
+CREATE TYPE typ AS ENUM('a', 'b', 'c')
+
+statement ok
+CREATE TABLE arr_t (i STRING DEFAULT ('{a}'::_typ)[1]::STRING)
+
+statement ok
+INSERT INTO arr_t VALUES (default)
+
+query T
+SELECT * FROM arr_t
+----
+a
+
+statement ok
+CREATE TABLE arr_t2 (i typ DEFAULT ('{a, b, c}'::typ[])[2])
+
+statement ok
+INSERT INTO arr_t2 VALUES (default)
+
+query T
+SELECT * FROM arr_t2
+----
+b
+
+statement ok
+CREATE TABLE arr_t3 (i STRING DEFAULT ('{c}'::_typ:::_typ)[1]::STRING)
+
+statement ok
+INSERT INTO arr_t3 VALUES (default)
+
+query T
+SELECT * FROM arr_t3
+----
+c

pkg/sql/sem/tree/expr.go

@@ -1624,7 +1624,15 @@ type IndirectionExpr struct {
 
 // Format implements the NodeFormatter interface.
 func (node *IndirectionExpr) Format(ctx *FmtCtx) {
-	exprFmtWithParen(ctx, node.Expr)
+	// If the subExpr is a CastExpr, we need to wrap it in a ParenExpr,
+	// otherwise the indirection will get interpreted as part of the type.
+	// Ex. ('{a}'::_typ)[1] vs. '{a}'::_typ[1].
+	if _, isCast := node.Expr.(*CastExpr); isCast {
+		withParens := ParenExpr{Expr: node.Expr}
+		exprFmtWithParen(ctx, &withParens)
+	} else {
+		exprFmtWithParen(ctx, node.Expr)
+	}
 	ctx.FormatNode(&node.Indirection)
 }
 

pkg/sql/sem/tree/type_check_test.go

@@ -196,6 +196,9 @@ func TestTypeCheck(t *testing.T) {
 		{`1:::d.s.t3 + 1.4`, `1:::DECIMAL + 1.4:::DECIMAL`},
 		{`1 IS OF (d.t1, t2)`, `1:::INT8 IS OF (INT8, STRING)`},
 		{`1::d.t1`, `1:::INT8`},
+
+		{`(('{' || 'a' ||'}')::STRING[])[1]::STRING`, `((('{':::STRING || 'a':::STRING) || '}':::STRING)::STRING[])[1:::INT8]`},
+		{`(('{' || '1' ||'}')::INT[])[1]`, `((('{':::STRING || '1':::STRING) || '}':::STRING)::INT8[])[1:::INT8]`},
 	}
 	ctx := context.Background()
 	for _, d := range testData {