}
		tp := tparams.At(i)
		w.writeType(buf, tp)
		if withConstraints {
			buf.WriteByte(' ')
			w.writeType(buf, tp.Constraint())
		}
	}
	buf.WriteByte(']')
}

func (w *Walker) writeParams(buf *bytes.Buffer, t *types.Tuple, variadic bool) {
	buf.WriteByte('(')
	for i, n := 0, t.Len(); i < n; i++ {
		if i > 0 {
			buf.WriteString(", ")
		}
		typ := t.At(i).Type()
		if variadic && i+1 == n {

pkg go/types, func TypeString(Type, Qualifier) string
pkg go/types, func WriteExpr(*bytes.Buffer, ast.Expr)
pkg go/types, func WriteSignature(*bytes.Buffer, *Signature, Qualifier)
pkg go/types, func WriteType(*bytes.Buffer, Type, Qualifier)
pkg go/types, method (*Array) Elem() Type
pkg go/types, method (*Array) Len() int64
pkg go/types, method (*Array) String() string
pkg go/types, method (*Array) Underlying() Type

						builder.WriteByte('(')
					}
				}

				c.Build(builder)

				if wrapInParentheses {
					builder.WriteByte(')')
				}
			}
		}

		if len(not.Exprs) > 1 {
			builder.WriteByte(')')
		}
	} else {
		builder.WriteString("NOT ")
		if len(not.Exprs) > 1 {
			builder.WriteByte('(')
		}

		for idx, c := range not.Exprs {

			if inName {
				if nv, ok := namedMap[string(name)]; ok {
					builder.AddVar(builder, nv)
				} else {
					builder.WriteByte('@')
					builder.WriteString(string(name))
				}
				inName = false
			}

			afterParenthesis = false
			builder.WriteByte(v)
		} else if v == '?' && len(expr.Vars) > idx {
			if afterParenthesis {
				if _, ok := expr.Vars[idx].(driver.Valuer); ok {

func (from From) Build(builder Builder) {
	if len(from.Tables) > 0 {
		for idx, table := range from.Tables {
			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(table)
		}
	} else {
		builder.WriteQuoted(currentTable)
	}

	for _, join := range from.Joins {
		builder.WriteByte(' ')
		join.Build(builder)
	}
}

// MergeClause merge from clause
func (from From) MergeClause(clause *Clause) {

	if onConflict.OnConstraint != "" {
		builder.WriteString("ON CONSTRAINT ")
		builder.WriteString(onConflict.OnConstraint)
		builder.WriteByte(' ')
	} else {
		if len(onConflict.Columns) > 0 {
			builder.WriteByte('(')
			for idx, column := range onConflict.Columns {
				if idx > 0 {
					builder.WriteByte(',')
				}
				builder.WriteQuoted(column)
			}
			builder.WriteString(`) `)
		}

			c.BeforeExpression.Build(builder)
			builder.WriteByte(' ')
		}

		if c.Name != "" {
			builder.WriteString(c.Name)
			builder.WriteByte(' ')
		}

		if c.AfterNameExpression != nil {
			c.AfterNameExpression.Build(builder)
			builder.WriteByte(' ')
		}

		c.Expression.Build(builder)

		if c.AfterExpression != nil {
			builder.WriteByte(' ')
			c.AfterExpression.Build(builder)
		}
	}
}

	for k := range c {
		sortedKeys = append(sortedKeys, k)
	}
	sort.Strings(sortedKeys)

	b.WriteByte('{')
	for i, k := range sortedKeys {
		b.WriteByte('"')
		escapeStringJSON(b, k)
		b.WriteString(`":"`)
		escapeStringJSON(b, c[k])
		b.WriteByte('"')
		if i < len(sortedKeys)-1 {
			b.WriteByte(',')
		}
	}
	b.WriteByte('}')
	return b.Bytes(), nil
}

// Adapted from Go stdlib.

func (returning Returning) Build(builder Builder) {
	if len(returning.Columns) > 0 {
		for idx, column := range returning.Columns {
			if idx > 0 {
				builder.WriteByte(',')
			}

			builder.WriteQuoted(column)
		}
	} else {
		builder.WriteByte('*')
	}
}

// MergeClause merge order by clauses
func (returning Returning) MergeClause(clause *Clause) {
	if v, ok := clause.Expression.(Returning); ok {

type Delete struct {
	Modifier string
}

func (d Delete) Name() string {
	return "DELETE"
}

func (d Delete) Build(builder Builder) {
	builder.WriteString("DELETE")

	if d.Modifier != "" {
		builder.WriteByte(' ')
		builder.WriteString(d.Modifier)
	}
}

func (d Delete) MergeClause(clause *Clause) {
	clause.Name = ""
	clause.Expression = d