c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := caseIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = caseIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

			return false
		}
		bp, _ = rb.f.quickSpan(rb.src, bp, len(s), true)
	}
	return true
}

// patchTail fixes a case where a rune may be incorrectly normalized
// if it is followed by illegal continuation bytes. It returns the
// patched buffer and whether the decomposition is still in progress.
func patchTail(rb *reorderBuffer) bool {
	info, p := lastRuneStart(&rb.f, rb.out)
	if p == -1 || info.size == 0 {

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		return t.lookupValue(uint32(i), c1), 2
	case c0 < 0xF0: // 3-byte UTF-8
		if len(s) < 3 {
			return 0, 0
		}
		i := bidiIndex[c0]
		c1 := s[1]
		if c1 < 0x80 || 0xC0 <= c1 {
			return 0, 1 // Illegal UTF-8: not a continuation byte.
		}
		o := uint32(i)<<6 + uint32(c1)
		i = bidiIndex[o]
		c2 := s[2]

// The position of the first call to addf determines the position of the reported Error.
// Subsequent calls to addf provide additional information in the form of additional lines
// in the error message (types2) or continuation errors identified by a tab-indented error
// message (go/types).
func (err *error_) addf(at positioner, format string, args ...interface{}) {
	err.desc = append(err.desc, errorDesc{at, err.check.sprintf(format, args...)})
}

		Lhs, Rhs Expr     // Rhs == nil means Lhs++ (Op == Add) or Lhs-- (Op == Sub)
		simpleStmt
	}

	BranchStmt struct {
		Tok   token // Break, Continue, Fallthrough, or Goto
		Label *Name
		// Target is the continuation of the control flow after executing
		// the branch; it is computed by the parser if CheckBranches is set.
		// Target is a *LabeledStmt for gotos, and a *SwitchStmt, *SelectStmt,

			return false
		}
		bp, _ = rb.f.quickSpan(rb.src, bp, len(s), true)
	}
	return true
}

// patchTail fixes a case where a rune may be incorrectly normalized
// if it is followed by illegal continuation bytes. It returns the
// patched buffer and whether the decomposition is still in progress.
func patchTail(rb *reorderBuffer) bool {
	info, p := lastRuneStart(&rb.f, rb.out)
	if p == -1 || info.size == 0 {

		list = c
	}
	if list == nil || list.bullet != rune(bullet) {
		// “When the first list item in a list interrupts a paragraph—that is,
		// when it starts on a line that would otherwise count as
		// paragraph continuation text—then (a) the lines Ls must
		// not begin with a blank line,
		// and (b) if the list item is ordered, the start number must be 1.”

	// TODO: track which type of frame & with which flags was sent
	// last. Then return an error (unless AllowIllegalWrites) if
	// we're in the middle of a header block and a
	// non-Continuation or Continuation on a different stream is
	// attempted to be written.

	logReads, logWrites bool

	debugFramer       *http2Framer // only use for logging written writes
	debugFramerBuf    *bytes.Buffer