index := -1 // index of matching error
		var delta int
		for _, i := range indices {
			if d := absDiff(gotPos.Column, errList[i].col); index < 0 || d < delta {
				index, delta = i, d
			}
		}

		// The closest column position must be within expected colDelta.
		const colDelta = 0 // go/types errors are positioned correctly
		if delta > colDelta {

//
// then this reader presents xxxyy. For well-formed PNG data, the decoder state
// immediately before the first Read call is that d.r is positioned between the
// first IDAT and xxx, and the decoder state immediately after the last Read
// call is that d.r is positioned between yy and crc1.
func (d *decoder) Read(p []byte) (int, error) {
	if len(p) == 0 {
		return 0, nil
	}
	for d.idatLength == 0 {

				// to match directives in the test data.
				name = "_empty"
			} else if spec, ok := d.Specs[0].(*ast.TypeSpec); ok {
				name = spec.Name.Name
			}
		}
		pos := fset.Position(decl.Pos()).Offset
		end := fset.Position(decl.End()).Offset
		if name == "" {
			prevEnd = end
			continue
		}
		for _, p := range outputDirectives {
			if !strings.HasPrefix(p.name, name) {
				continue
			}

		return r.p.tparamIndex[id]

	case instanceType:
		if r.p.exportVersion < iexportVersionGenerics {
			errorf("unexpected instantiation type")
		}
		// pos does not matter for instances: they are positioned on the original
		// type.
		_ = r.pos()
		len := r.uint64()
		targs := make([]types.Type, len)
		for i := range targs {
			targs[i] = r.typ()
		}
		baseType := r.typ()

	// Positions
	// The out position differs from the pos position when the result
	// formatting differs from the source formatting (in the amount of
	// white space). If there's a difference and SourcePos is set in
	// ConfigMode, //line directives are used in the output to restore
	// original source positions for a reader.
	pos          token.Position // current position in AST (source) space

func (r *Reader) offset() Offset {
	return r.b.off
}

// SeekPC returns the [Entry] for the compilation unit that includes pc,
// and positions the reader to read the children of that unit.  If pc
// is not covered by any unit, SeekPC returns [ErrUnknownPC] and the
// position of the reader is undefined.
//
// Because compilation units can describe multiple regions of the

  void removeEntryValueHashKnown(int entry, int valueHash) {
    removeEntry(entry, Hashing.smearedHash(keys[entry]), valueHash);
  }

  /**
   * Moves the entry previously positioned at {@code src} to {@code dest}. Assumes the entry
   * previously at {@code src} has already been removed from the data structures.
   */
  private void moveEntryToIndex(int src, int dest) {
    if (src == dest) {

// //line comments; otherwise those comments are ignored.
// p must be a Pos value in f or NoPos.
func (f *File) PositionFor(p Pos, adjusted bool) (pos Position) {
	if p != NoPos {
		pos = f.position(p, adjusted)
	}
	return
}

// Position returns the Position value for the given file position p.
// If p is out of bounds, it is adjusted to match the File.Offset behavior.

// will be read to completion and the entire trace will be materialized in
// memory. That is, this function does not allow incremental parsing.
//
// The reader has to be positioned just after the trace header and vers needs to
// be the version of the trace. This can be achieved by using
// version.ReadHeader.
func Parse(r io.Reader, vers version.Version) (Trace, error) {

//
// The position base is used to determine the "relative" position, that is the
// filename and line number relative to the position base. If the base refers
// to the current file, there is no difference between absolute and relative
// positions. If it refers to a //line directive, a relative position is relative
// to that directive. A position base in turn contains the position at which it
// was introduced in the current file.
type Pos struct {