tree: optionally treat string constants as collated

Previously, the type checker would reject comparisons between string
constants and collated collated strings without an explicit type cast.
This patch relaxes that restriction so that comparison of collated
strings against string literals does the collated comparison as one
would expect.

Fixes #133141

Release note (bug fix): String constants can now be compared against
collated strings.

pkg/sql/logictest/testdata/logic_test/collatedstring

@@ -1,8 +1,10 @@
 statement error pq: invalid locale bad_locale: language: subtag "locale" is well-formed but unknown
 SELECT 'a' COLLATE bad_locale
 
-statement error pq: unsupported comparison operator: <collatedstring{en}> = <string>
+query B 
 SELECT 'A' COLLATE en = 'a'
+----
+false
 
 statement error pq: unsupported comparison operator: <collatedstring{en}> = <collatedstring{de}>
 SELECT 'A' COLLATE en = 'a' COLLATE de
@@ -560,3 +562,51 @@ SELECT * FROM t45142 WHERE c < SOME ('' COLLATE en, '' COLLATE de);
 statement ok
 SELECT * FROM t45142 WHERE c < SOME (CASE WHEN true THEN NULL END, '' COLLATE en);
 SELECT * FROM t45142 WHERE c < SOME ('' COLLATE en, CASE WHEN true THEN NULL END);
+
+subtest issue_132867
+
+statement ok
+CREATE TABLE test_collate (
+  id INT8 PRIMARY KEY,
+  "string_field" STRING COLLATE en_US_u_ks_level2 NULL
+)
+
+statement ok
+INSERT INTO test_collate VALUES (1, 'Str_Collate_1')
+
+query IT
+SELECT * FROM test_collate WHERE (("id", "string_field")) = ANY(Array[(1, 'str_collate_1')])
+----
+1  Str_Collate_1
+
+query I
+SELECT id FROM test_collate WHERE "string_field" = 'sTR_cOLLATE_1'
+----
+1
+
+statement ok
+INSERT INTO test_collate VALUES (2, 'Foo'), (3, 'Bar'), (4, 'Baz')
+
+query T
+SELECT string_field FROM test_collate WHERE string_field < 'baz' ORDER BY id
+----
+Bar
+
+query T
+SELECT string_field FROM test_collate WHERE string_field <= 'baz' ORDER BY id
+----
+Bar
+Baz
+
+query T
+SELECT string_field FROM test_collate WHERE string_field > 'baz' ORDER BY id
+----
+Str_Collate_1
+Foo
+
+query T
+SELECT string_field FROM test_collate WHERE string_field >= 'baz' ORDER BY id
+----
+Str_Collate_1
+Foo
+Baz

pkg/sql/sem/tree/constant.go

@@ -507,6 +507,7 @@ var (
 		// default type that raw strings get parsed into, without any casts or type
 		// assertions.
 		types.String,
+		types.AnyCollatedString,
 		types.Bytes,
 		types.Bool,
 		types.Int,

pkg/sql/sem/tree/constant_test.go

@@ -44,6 +44,12 @@ func TestAvailTypesAreSets(t *testing.T) {
 	for i, test := range testCases {
 		seen := make(map[oid.Oid]struct{})
 		for _, newType := range test.availTypes {
+			// Collated strings have the same Oid as uncollated strings, but we need the
+			// ability to parse constants as collated strings when that is the desired
+			// type.
+			if newType.Family() == types.CollatedStringFamily {
+				continue
+			}
 			if _, ok := seen[newType.Oid()]; ok {
 				t.Errorf("%d: found duplicate type: %v", i, newType)
 			}
@@ -214,6 +220,13 @@ func TestStringConstantVerifyAvailableTypes(t *testing.T) {
 				continue
 			}
 
+			// The collated string value in c.AvailableTypes() is AnyCollatedString, so we
+			// will not be able to resolve that exact type. In actual execution, the constant
+			// would be resolved with an actual desired locale.
+			if availType.Family() == types.CollatedStringFamily {
+				continue
+			}
+
 			semaCtx := tree.MakeSemaContext(nil /* resolver */)
 			if _, err := test.c.ResolveAsType(context.Background(), &semaCtx, availType); err != nil {
 				if !strings.Contains(err.Error(), "could not parse") &&
@@ -680,6 +693,13 @@ func TestStringConstantResolveAvailableTypes(t *testing.T) {
 					continue
 				}
 
+				// The collated string value in c.AvailableTypes() is AnyCollatedString, so we
+				// will not be able to resolve that exact type. In actual execution, the constant
+				// would be resolved with an actual desired locale.
+				if availType.Family() == types.CollatedStringFamily {
+					continue
+				}
+
 				semaCtx := tree.MakeSemaContext(nil /* resolver */)
 				typedExpr, err := test.c.ResolveAsType(ctx, &semaCtx, availType)
 				var res tree.Datum