refactor(ast): Removed redundant type ast.Const (no parsers which produce instance of this type)

Author: asmyasnikov

internal/sql/ast/const.go

@@ -496,9 +496,6 @@ func (a *application) apply(parent ast.Node, name string, iter *iterator, n ast.
 	case *ast.CompositeTypeStmt:
 		a.apply(n, "TypeName", nil, n.TypeName)
 
-	case *ast.Const:
-		a.apply(n, "Xpr", nil, n.Xpr)
-
 	case *ast.Constraint:
 		a.apply(n, "RawExpr", nil, n.RawExpr)
 		a.apply(n, "Keys", nil, n.Keys)

internal/sql/astutils/rewrite.go

@@ -665,11 +665,6 @@ func Walk(f Visitor, node ast.Node) {
 			Walk(f, n.Ctecolcollations)
 		}
 
-	case *ast.Const:
-		if n.Xpr != nil {
-			Walk(f, n.Xpr)
-		}
-
 	case *ast.Constraint:
 		if n.RawExpr != nil {
 			Walk(f, n.RawExpr)