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// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file implements various error reporters.
package types
import (
"errors"
"fmt"
"go/ast"
"go/token"
"strconv"
"strings"
)
func assert(p bool) {
if !p {
panic("assertion failed")
}
}
func unreachable() {
panic("unreachable")
}
func (check *Checker) qualifier(pkg *Package) string {
// Qualify the package unless it's the package being type-checked.
if pkg != check.pkg {
// If the same package name was used by multiple packages, display the full path.
if check.pkgCnt[pkg.name] > 1 {
return strconv.Quote(pkg.path)
}
return pkg.name
}
return ""
}
func (check *Checker) sprintf(format string, args ...interface{}) string {
for i, arg := range args {
switch a := arg.(type) {
case nil:
arg = "<nil>"
case operand:
panic("internal error: should always pass *operand")
case *operand:
arg = operandString(a, check.qualifier)
case token.Pos:
arg = check.fset.Position(a).String()
case ast.Expr:
arg = ExprString(a)
case Object:
arg = ObjectString(a, check.qualifier)
case Type:
arg = TypeString(a, check.qualifier)
}
args[i] = arg
}
return fmt.Sprintf(format, args...)
}
func (check *Checker) trace(pos token.Pos, format string, args ...interface{}) {
fmt.Printf("%s:\t%s%s\n",
check.fset.Position(pos),
strings.Repeat(". ", check.indent),
check.sprintf(format, args...),
)
}
// dump is only needed for debugging
func (check *Checker) dump(format string, args ...interface{}) {
fmt.Println(check.sprintf(format, args...))
}
func (check *Checker) err(err error) {
if err == nil {
return
}
var e Error
isInternal := errors.As(err, &e)
// Cheap trick: Don't report errors with messages containing
// "invalid operand" or "invalid type" as those tend to be
// follow-on errors which don't add useful information. Only
// exclude them if these strings are not at the beginning,
// and only if we have at least one error already reported.
isInvalidErr := isInternal && (strings.Index(e.Msg, "invalid operand") > 0 || strings.Index(e.Msg, "invalid type") > 0)
if check.firstErr != nil && isInvalidErr {
return
}
if check.firstErr == nil {
check.firstErr = err
}
if trace {
pos := e.Pos
msg := e.Msg
if !isInternal {
msg = err.Error()
pos = token.NoPos
}
check.trace(pos, "ERROR: %s", msg)
}
f := check.conf.Error
if f == nil {
panic(bailout{}) // report only first error
}
f(err)
}
func (check *Checker) newError(at positioner, code errorCode, soft bool, msg string) error {
ext := spanOf(at)
return Error{
Fset: check.fset,
Pos: ext.pos,
Msg: msg,
Soft: soft,
go116code: code,
go116start: ext.start,
go116end: ext.end,
}
}
// newErrorf creates a new Error, but does not handle it.
func (check *Checker) newErrorf(at positioner, code errorCode, soft bool, format string, args ...interface{}) error {
msg := check.sprintf(format, args...)
return check.newError(at, code, soft, msg)
}
func (check *Checker) error(at positioner, code errorCode, msg string) {
check.err(check.newError(at, code, false, msg))
}
func (check *Checker) errorf(at positioner, code errorCode, format string, args ...interface{}) {
check.error(at, code, check.sprintf(format, args...))
}
func (check *Checker) softErrorf(at positioner, code errorCode, format string, args ...interface{}) {
check.err(check.newErrorf(at, code, true, format, args...))
}
func (check *Checker) invalidAST(at positioner, format string, args ...interface{}) {
check.errorf(at, 0, "invalid AST: "+format, args...)
}
func (check *Checker) invalidArg(at positioner, code errorCode, format string, args ...interface{}) {
check.errorf(at, code, "invalid argument: "+format, args...)
}
func (check *Checker) invalidOp(at positioner, code errorCode, format string, args ...interface{}) {
check.errorf(at, code, "invalid operation: "+format, args...)
}
// The positioner interface is used to extract the position of type-checker
// errors.
type positioner interface {
Pos() token.Pos
}
// posSpan holds a position range along with a highlighted position within that
// range. This is used for positioning errors, with pos by convention being the
// first position in the source where the error is known to exist, and start
// and end defining the full span of syntax being considered when the error was
// detected. Invariant: start <= pos < end || start == pos == end.
type posSpan struct {
start, pos, end token.Pos
}
func (e posSpan) Pos() token.Pos {
return e.pos
}
// inNode creates a posSpan for the given node.
// Invariant: node.Pos() <= pos < node.End() (node.End() is the position of the
// first byte after node within the source).
func inNode(node ast.Node, pos token.Pos) posSpan {
start, end := node.Pos(), node.End()
if debug {
assert(start <= pos && pos < end)
}
return posSpan{start, pos, end}
}
// atPos wraps a token.Pos to implement the positioner interface.
type atPos token.Pos
func (s atPos) Pos() token.Pos {
return token.Pos(s)
}
// spanOf extracts an error span from the given positioner. By default this is
// the trivial span starting and ending at pos, but this span is expanded when
// the argument naturally corresponds to a span of source code.
func spanOf(at positioner) posSpan {
switch x := at.(type) {
case nil:
panic("internal error: nil")
case posSpan:
return x
case ast.Node:
pos := x.Pos()
return posSpan{pos, pos, x.End()}
case *operand:
if x.expr != nil {
pos := x.Pos()
return posSpan{pos, pos, x.expr.End()}
}
return posSpan{token.NoPos, token.NoPos, token.NoPos}
default:
pos := at.Pos()
return posSpan{pos, pos, pos}
}
}