github.com/hikaru7719/go@v0.0.0-20181025140707-c8b2ac68906a/src/go/types/errors.go (about)

     1  // Copyright 2012 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  // This file implements various error reporters.
     6  
     7  package types
     8  
     9  import (
    10  	"fmt"
    11  	"go/ast"
    12  	"go/token"
    13  	"strings"
    14  )
    15  
    16  func assert(p bool) {
    17  	if !p {
    18  		panic("assertion failed")
    19  	}
    20  }
    21  
    22  func unreachable() {
    23  	panic("unreachable")
    24  }
    25  
    26  func (check *Checker) qualifier(pkg *Package) string {
    27  	if pkg != check.pkg {
    28  		return pkg.path
    29  	}
    30  	return ""
    31  }
    32  
    33  func (check *Checker) sprintf(format string, args ...interface{}) string {
    34  	for i, arg := range args {
    35  		switch a := arg.(type) {
    36  		case nil:
    37  			arg = "<nil>"
    38  		case operand:
    39  			panic("internal error: should always pass *operand")
    40  		case *operand:
    41  			arg = operandString(a, check.qualifier)
    42  		case token.Pos:
    43  			arg = check.fset.Position(a).String()
    44  		case ast.Expr:
    45  			arg = ExprString(a)
    46  		case Object:
    47  			arg = ObjectString(a, check.qualifier)
    48  		case Type:
    49  			arg = TypeString(a, check.qualifier)
    50  		}
    51  		args[i] = arg
    52  	}
    53  	return fmt.Sprintf(format, args...)
    54  }
    55  
    56  func (check *Checker) trace(pos token.Pos, format string, args ...interface{}) {
    57  	fmt.Printf("%s:\t%s%s\n",
    58  		check.fset.Position(pos),
    59  		strings.Repeat(".  ", check.indent),
    60  		check.sprintf(format, args...),
    61  	)
    62  }
    63  
    64  // dump is only needed for debugging
    65  func (check *Checker) dump(format string, args ...interface{}) {
    66  	fmt.Println(check.sprintf(format, args...))
    67  }
    68  
    69  func (check *Checker) err(pos token.Pos, msg string, soft bool) {
    70  	// Cheap trick: Don't report errors with messages containing
    71  	// "invalid operand" or "invalid type" as those tend to be
    72  	// follow-on errors which don't add useful information. Only
    73  	// exclude them if these strings are not at the beginning,
    74  	// and only if we have at least one error already reported.
    75  	if check.firstErr != nil && (strings.Index(msg, "invalid operand") > 0 || strings.Index(msg, "invalid type") > 0) {
    76  		return
    77  	}
    78  
    79  	err := Error{check.fset, pos, msg, soft}
    80  	if check.firstErr == nil {
    81  		check.firstErr = err
    82  	}
    83  
    84  	f := check.conf.Error
    85  	if f == nil {
    86  		panic(bailout{}) // report only first error
    87  	}
    88  	f(err)
    89  }
    90  
    91  func (check *Checker) error(pos token.Pos, msg string) {
    92  	check.err(pos, msg, false)
    93  }
    94  
    95  func (check *Checker) errorf(pos token.Pos, format string, args ...interface{}) {
    96  	check.err(pos, check.sprintf(format, args...), false)
    97  }
    98  
    99  func (check *Checker) softErrorf(pos token.Pos, format string, args ...interface{}) {
   100  	check.err(pos, check.sprintf(format, args...), true)
   101  }
   102  
   103  func (check *Checker) invalidAST(pos token.Pos, format string, args ...interface{}) {
   104  	check.errorf(pos, "invalid AST: "+format, args...)
   105  }
   106  
   107  func (check *Checker) invalidArg(pos token.Pos, format string, args ...interface{}) {
   108  	check.errorf(pos, "invalid argument: "+format, args...)
   109  }
   110  
   111  func (check *Checker) invalidOp(pos token.Pos, format string, args ...interface{}) {
   112  	check.errorf(pos, "invalid operation: "+format, args...)
   113  }