Merge pull request #3262 from dolthub/elian/9927b

dolthub/dolt#9927: Fix SQL regression on UnaryMinus NULL CAST

Author: elianddb

enginetest/queries/script_queries.go

@@ -244,6 +244,8 @@ var ScriptTests = []ScriptTest{
 			"INSERT INTO t2(c0) VALUES (-32768);",
 			"CREATE TABLE t3(c0 TINYINT);",
 			"INSERT INTO t3(c0) VALUES (-128);",
+			"CREATE TABLE tab1 (col4 INT)",
+			"INSERT INTO tab1 VALUES (10), (20), (30)",
 		},
 		Assertions: []ScriptTestAssertion{
 			{
@@ -311,6 +313,10 @@ var ScriptTests = []ScriptTest{
 				Expected:        []sql.Row{{int64(-128)}},
 				ExpectedColumns: sql.Schema{{Name: "-(-CAST(-128 AS SIGNED))", Type: types.Int64}},
 			},
+			{
+				Query:    "SELECT * FROM tab1 AS cor0 WHERE NOT - CAST(NULL AS SIGNED) < +35 * +col4 + - -39",
+				Expected: []sql.Row{},
+			},
 		},
 	},
 	{

sql/expression/arithmetic.go

@@ -757,8 +757,9 @@ func (e *UnaryMinus) Type() sql.Type {
 		typ = types.Int64
 	case types.Int64:
 		if lit, ok := e.Child.(*Literal); ok {
-			if lit.Value().(int64) == math.MinInt64 {
-				typ = types.InternalDecimalType
+			// lit.Value() can be nil
+			if v, ok := lit.Value().(int64); ok && v == math.MinInt64 {
+				return types.InternalDecimalType
 			}
 		}
 	}