d.Specs = specs

		// Deduping can leave a blank line before the rparen; clean that up.
		if len(d.Specs) > 0 {
			lastSpec := d.Specs[len(d.Specs)-1]
			lastLine := lineAt(fset, lastSpec.Pos())
			rParenLine := lineAt(fset, d.Rparen)
			for rParenLine > lastLine+1 {
				rParenLine--
				fset.File(d.Rparen).MergeLine(rParenLine)
			}
		}
	}
}

func lineAt(fset *token.FileSet, pos token.Pos) int {

		block = append(block, tabwriter.Escape, '\n')
		if len(p.plusBuild) > 0 {
			lines, err := constraint.PlusBuildLines(x)
			if err != nil {
				lines = []string{"// +build error: " + err.Error()}
			}
			for _, line := range lines {
				block = append(block, tabwriter.Escape)
				block = append(block, line...)
				block = append(block, tabwriter.Escape, '\n')
			}
		}
	}
	block = append(block, '\n')

// before empty lines.
func TestIssue5945(t *testing.T) {
	const orig = `
package p   // line 2
func f() {} // line 3

var x, y, z int


func g() { // line 8
}
`

	const want = `//line src.go:2
package p

//line src.go:3
func f() {}

var x, y, z int

//line src.go:8
func g() {
}
`

	buf := makeBuf(d, u, "line", Offset(off), d.line[off:])
	// The compilation directory is implicitly directories[0].
	r := LineReader{
		buf:     buf,
		section: d.line,
		str:     d.str,
		lineStr: d.lineStr,
	}

	// Read the header.
	if err := r.readHeader(compDir); err != nil {
		return nil, err
	}

	// Initialize line reader state.
	r.Reset()

	return &r, nil
}

	{"\n//line foo 42\n  line44", "foo\t", 46, 0},  // bad line comment, ignored (use existing, prior filename)
	{"\n//line /bar:42\n  line45", "/bar", 42, 0},
	{"\n//line ./foo:42\n  line46", "foo", 42, 0},
	{"\n//line a/b/c/File1.go:100\n  line100", "a/b/c/File1.go", 100, 0},
	{"\n//line c:\\bar:42\n  line200", "c:\\bar", 42, 0},
	{"\n//line c:\\dir\\File1.go:100\n  line201", "c:\\dir\\File1.go", 100, 0},

	// tests for new line directive syntax

#include "line1.h"

void f2();

int main()
{
	f1();
	f2();

Austin Clements <******@****.***> 1425666364 -0500

Austin Clements <******@****.***> 1425666364 -0500

Russ Cox <******@****.***> 1669995570 -0500

}

// getFileIndexAndLine returns the relative file index (local to the CU), and
// the relative line number for a position (i.e., as adjusted by a //line
// directive). This is the file/line visible in the final binary (pcfile, pcln,
// etc).
func (ctxt *Link) getFileIndexAndLine(xpos src.XPos) (int, int32) {
	pos := ctxt.InnermostPos(xpos)
	if !pos.IsKnown() {