Source file src/go/types/errors.go

     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		"path"
    14		"strings"
    15	)
    16	
    17	func assert(p bool) {
    18		if !p {
    19			panic("assertion failed")
    20		}
    21	}
    22	
    23	func unreachable() {
    24		panic("unreachable")
    25	}
    26	
    27	func (check *Checker) qualifier(pkg *Package) string {
    28		if pkg != check.pkg {
    29			return path.Base(pkg.path) // avoid excessively long path names in error messages
    30		}
    31		return ""
    32	}
    33	
    34	func (check *Checker) sprintf(format string, args ...interface{}) string {
    35		for i, arg := range args {
    36			switch a := arg.(type) {
    37			case nil:
    38				arg = "<nil>"
    39			case operand:
    40				panic("internal error: should always pass *operand")
    41			case *operand:
    42				arg = operandString(a, check.qualifier)
    43			case token.Pos:
    44				arg = check.fset.Position(a).String()
    45			case ast.Expr:
    46				arg = ExprString(a)
    47			case Object:
    48				arg = ObjectString(a, check.qualifier)
    49			case Type:
    50				arg = TypeString(a, check.qualifier)
    51			}
    52			args[i] = arg
    53		}
    54		return fmt.Sprintf(format, args...)
    55	}
    56	
    57	func (check *Checker) trace(pos token.Pos, format string, args ...interface{}) {
    58		fmt.Printf("%s:\t%s%s\n",
    59			check.fset.Position(pos),
    60			strings.Repeat(".  ", check.indent),
    61			check.sprintf(format, args...),
    62		)
    63	}
    64	
    65	// dump is only needed for debugging
    66	func (check *Checker) dump(format string, args ...interface{}) {
    67		fmt.Println(check.sprintf(format, args...))
    68	}
    69	
    70	func (check *Checker) err(pos token.Pos, msg string, soft bool) {
    71		// Cheap trick: Don't report errors with messages containing
    72		// "invalid operand" or "invalid type" as those tend to be
    73		// follow-on errors which don't add useful information. Only
    74		// exclude them if these strings are not at the beginning,
    75		// and only if we have at least one error already reported.
    76		if check.firstErr != nil && (strings.Index(msg, "invalid operand") > 0 || strings.Index(msg, "invalid type") > 0) {
    77			return
    78		}
    79	
    80		err := Error{check.fset, pos, msg, soft}
    81		if check.firstErr == nil {
    82			check.firstErr = err
    83		}
    84	
    85		f := check.conf.Error
    86		if f == nil {
    87			panic(bailout{}) // report only first error
    88		}
    89		f(err)
    90	}
    91	
    92	func (check *Checker) error(pos token.Pos, msg string) {
    93		check.err(pos, msg, false)
    94	}
    95	
    96	func (check *Checker) errorf(pos token.Pos, format string, args ...interface{}) {
    97		check.err(pos, check.sprintf(format, args...), false)
    98	}
    99	
   100	func (check *Checker) softErrorf(pos token.Pos, format string, args ...interface{}) {
   101		check.err(pos, check.sprintf(format, args...), true)
   102	}
   103	
   104	func (check *Checker) invalidAST(pos token.Pos, format string, args ...interface{}) {
   105		check.errorf(pos, "invalid AST: "+format, args...)
   106	}
   107	
   108	func (check *Checker) invalidArg(pos token.Pos, format string, args ...interface{}) {
   109		check.errorf(pos, "invalid argument: "+format, args...)
   110	}
   111	
   112	func (check *Checker) invalidOp(pos token.Pos, format string, args ...interface{}) {
   113		check.errorf(pos, "invalid operation: "+format, args...)
   114	}
   115	

View as plain text