func MakePos(base *PosBase, line, col uint) Pos { return Pos{base, sat32(line), sat32(col)} }

// TODO(gri) IsKnown makes an assumption about linebase < 1.
// Maybe we should check for Base() != nil instead.

func (pos Pos) Pos() Pos       { return pos }
func (pos Pos) IsKnown() bool  { return pos.line > 0 }
func (pos Pos) Base() *PosBase { return pos.base }

	}
	return x.Lbrace
}
func (x *ParenExpr) Pos() token.Pos      { return x.Lparen }
func (x *SelectorExpr) Pos() token.Pos   { return x.X.Pos() }
func (x *IndexExpr) Pos() token.Pos      { return x.X.Pos() }
func (x *IndexListExpr) Pos() token.Pos  { return x.X.Pos() }
func (x *SliceExpr) Pos() token.Pos      { return x.X.Pos() }
func (x *TypeAssertExpr) Pos() token.Pos { return x.X.Pos() }

	nifnz := ir.NewIfStmt(base.Pos, ir.NewBinaryExpr(base.Pos, ir.ONE, l2, ir.NewInt(base.Pos, 0)), nil, nil)
	nifnz.Likely = true
	nodes = append(nodes, nifnz)

	elemtype := s.Type().Elem()

	// n := s.len + l2
	nn := typecheck.TempAt(base.Pos, ir.CurFunc, types.Types[types.TINT])
	nifnz.Body = append(nifnz.Body, ir.NewAssignStmt(base.Pos, nn, ir.NewBinaryExpr(base.Pos, ir.OADD, ir.NewUnaryExpr(base.Pos, ir.OLEN, s), l2)))

			}
			m = n.Type

		// expressions
		case *BadExpr:
			return n.Pos()
		case *Name:
			p := n.Pos()
			return MakePos(p.Base(), p.Line(), p.Col()+uint(len(n.Value)))
		case *BasicLit:
			p := n.Pos()
			return MakePos(p.Base(), p.Line(), p.Col()+uint(len(n.Value)))
		case *CompositeLit:
			return n.Rbrace
		case *KeyValueExpr:
			m = n.Value
		case *FuncLit:
			m = n.Body

			check.inStar = true
			i++
			pos += token.Pos(i)
			text = text[i:]
			for text != "" {
				i := strings.Index(text, "\n")
				if i < 0 {
					i = len(text)
				} else {
					i++
				}
				line := text[:i]
				if strings.HasPrefix(line, "//") {
					check.comment(pos, line)
				}
				pos += token.Pos(i)
				text = text[i:]
			}
			check.inStar = false
		}

		}
	}

	want := []devirtualization{
		// ExerciseIface
		{
			pos:    "./devirt.go:101:20",
			callee: "mult.Mult.Multiply",
		},
		{
			pos:    "./devirt.go:101:39",
			callee: "Add.Add",
		},
		// ExerciseFuncConcrete
		{
			pos:    "./devirt.go:173:36",
			callee: "AddFn",
		},
		{
			pos:    "./devirt.go:173:15",
			callee: "mult.MultFn",
		},
		// ExerciseFuncField

		// Types don't generally have position information.
		// If we don't have a valid pos provided, try to use
		// one close enough.
		if !pos.IsKnown() && len(ityp.methods) > 0 {
			pos = ityp.methods[0].pos
		}

		check.trace(pos, "-- type set for %s", ityp)
		check.indent++
		defer func() {
			check.indent--
			check.trace(pos, "=> %s ", ityp.typeSet())
		}()
	}

				// Check if it's a literal string, otherwise we can't suggest a fix.
				if _, ok := arg.(*ast.BasicLit); ok {
					pos := int(arg.Pos()) + badAt + 1 // +1 to skip the " or `
					end := pos + len(badFormat)

					pass.Report(analysis.Diagnostic{
						Pos:     token.Pos(pos),
						End:     token.Pos(end),
						Message: badFormat + " should be " + goodFormat,
						SuggestedFixes: []analysis.SuggestedFix{{

			// Search within this run of same-length strings.
			pos := run[0].pos
			s.done.Append(ir.NewLabelStmt(pos, label))
			stringSearch(s.exprname, run, &s.done)
			s.done.Append(ir.NewBranchStmt(pos, ir.OGOTO, endLabel))

			// Add length case to outer switch.
			cas := ir.NewInt(pos, runLen(run))
			jmp := ir.NewBranchStmt(pos, ir.OGOTO, label)
			outer.Add(pos, cas, nil, jmp)
		}

func (err *error_) addAltDecl(obj Object) {
	if pos := obj.Pos(); pos.IsKnown() {
		// We use "other" rather than "previous" here because
		// the first declaration seen may not be textually
		// earlier in the source.
		err.addf(obj, "other declaration of %s", obj.Name())
	}
}

func (err *error_) empty() bool {
	return err.desc == nil
}

func (err *error_) pos() syntax.Pos {
	if err.empty() {
		return nopos
	}