stdlib v3.15.2

erl_lint (stdlib v3.15.2)

This module is used to check Erlang code for illegal syntax and other bugs. It also warns against coding practices that are not recommended.

The errors detected include:

  • Redefined and undefined functions
  • Unbound and unsafe variables
  • Illegal record use

The warnings detected include:

  • Unused functions and imports
  • Unused variables
  • Variables imported into matches
  • Variables exported from if/case/receive
  • Variables shadowed in funs and list comprehensions

Some of the warnings are optional, and can be turned on by specifying the appropriate option, described below.

The functions in this module are invoked automatically by the Erlang compiler. There is no reason to invoke these functions separately unless you have written your own Erlang compiler.

Error Information

ErrorInfo is the standard ErrorInfo structure that is returned from all I/O modules. The format is as follows:

{ErrorLine, Module, ErrorDescriptor}

A string describing the error is obtained with the following call:

Module:format_error(ErrorDescriptor)

See Also

epp(3), erl_parse(3)

Link to this section Summary

Types

-type error_description() :: term().
-type error_info() :: term().

Functions

format_error/1

Takes an ErrorDescriptor and returns a string that describes the error or warning. This function is usually called implicitly when processing an ErrorInfo structure (see section Error Information).

is_guard_test/1

Tests if Expr is a legal guard test. Expr is an Erlang term representing the abstract form for the expression. erl_parse:parse_exprs(Tokens) can be used to generate a list of Expr.

module/1

Checks all the forms in a module for errors. It returns

module/2
module/3

Link to this section Types

Link to this type

-type error_description() :: term().

Specs

error_description() :: term().
Link to this type

-type error_info() :: term().

Specs

error_info() :: {erl_anno:location() | none, module(), error_description()}.

Link to this section Functions

Link to this function

format_error/1

Specs

format_error(ErrorDescriptor) -> io_lib:chars() when ErrorDescriptor :: error_description().

Takes an ErrorDescriptor and returns a string that describes the error or warning. This function is usually called implicitly when processing an ErrorInfo structure (see section Error Information).

Link to this function

is_guard_test/1

Specs

is_guard_test(Expr) -> boolean() when Expr :: erl_parse:abstract_expr().

Tests if Expr is a legal guard test. Expr is an Erlang term representing the abstract form for the expression. erl_parse:parse_exprs(Tokens) can be used to generate a list of Expr.

Link to this function

module/1

Specs

module(AbsForms) -> {ok, Warnings} | {error, Errors, Warnings}
          when
              AbsForms :: [erl_parse:abstract_form() | erl_parse:form_info()],
              Warnings :: [{SourceFile, [ErrorInfo]}],
              Errors :: [{SourceFile, [ErrorInfo]}],
              SourceFile :: file:filename(),
              ErrorInfo :: error_info().

Checks all the forms in a module for errors. It returns:

{ok,Warnings}

There are no errors in the module.

{error,Errors,Warnings}

There are errors in the module.

As this module is of interest only to the maintainers of the compiler, and to avoid the same description in two places, the elements of Options that control the warnings are only described in the compile(3) module.

AbsForms of a module, which comes from a file that is read through epp, the Erlang preprocessor, can come from many files. This means that any references to errors must include the filename, see the epp(3) module or parser (see the erl_parse(3) module). The returned errors and warnings have the following format:

[{SourceFile,[ErrorInfo]}]

The errors and warnings are listed in the order in which they are encountered in the forms. The errors from one file can therefore be split into different entries in the list of errors.

Link to this function

module/2

Specs

module(AbsForms, FileName) -> {ok, Warnings} | {error, Errors, Warnings}
          when
              AbsForms :: [erl_parse:abstract_form() | erl_parse:form_info()],
              FileName :: atom() | string(),
              Warnings :: [{SourceFile, [ErrorInfo]}],
              Errors :: [{SourceFile, [ErrorInfo]}],
              SourceFile :: file:filename(),
              ErrorInfo :: error_info().
Link to this function

module/3

Specs

module(AbsForms, FileName, CompileOptions) -> {ok, Warnings} | {error, Errors, Warnings}
          when
              AbsForms :: [erl_parse:abstract_form() | erl_parse:form_info()],
              FileName :: atom() | string(),
              CompileOptions :: [compile:option()],
              Warnings :: [{SourceFile, [ErrorInfo]}],
              Errors :: [{SourceFile, [ErrorInfo]}],
              SourceFile :: file:filename(),
              ErrorInfo :: error_info().