#10021: Add "Error:" prefix for compile-time error messages -------------------------------------+------------------------------------- Reporter: k-bx | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.8.4 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Blocked By: | Test Case: Related Tickets: | Blocking: | Differential Revisions: -------------------------------------+------------------------------------- Description changed by spl: Old description:
We propose adding the prefix `Error:` to compile-time error messages produced by GHC.
An example of a warning message (see `Warning:` prefix):
{{{ ➜ cat test.hs main = putStrLn "Hello!" ➜ ghc --make -fforce-recomp -Wall ./test.hs [1 of 1] Compiling Main ( test.hs, test.o )
test.hs:1:1: Warning: Top-level binding with no type signature: main :: IO () Linking test ... }}}
An example of a current error message:
{{{ ➜ cat test2.hs main = foo ➜ ghc --make -fforce-recomp -Wall ./test2.hs [1 of 1] Compiling Main ( test2.hs, test2.o )
test2.hs:1:8: Not in scope: ‘foo’ }}}
The proposal is to change the error message to become:
{{{ ➜ cat test2.hs main = foo ➜ ghc --make -fforce-recomp -Wall ./test2.hs [1 of 1] Compiling Main ( test2.hs, test2.o )
test2.hs:1:8: Error: Not in scope: ‘foo’ }}}
This change affects only the error messages produced by GHC when compiling. It does not change runtime error reporting, e.g. with the `error` function.
== Motivation ==
We wish to make compile-time error messages easier for humans and computers to identify. For example, when running a long parallel build, it can be easy to miss an error message (see #9219 for an example). With a known string such as `Error:`, we can use search functionality in a terminal window or text editor (when viewing the build log) or use a command-line tool such as `grep` (when streaming and filtering the build log) to quickly find errors.
As a secondary motivation, adding `Error:` for error messages brings a nice symmetry to the current use of `Warning:` for warning messages.
== Disadvantages ==
The output of many regression tests will need to be updated for the new error message format.
== Additional consideration ==
@hvr proposed that during work on this bug we could make GHC output more consistent with other compiler's (GCC and clang) by also lower-casing "Error" and "Warning" prefixes.
This might be potentially useful for existing tools that work on top of compiler output for finding errors/warning, and GHC's output will become "more valid" for them.
New description: We propose adding the prefix `Error:` to compile-time error messages produced by GHC. An example of a warning message (see `Warning:` prefix): {{{ ➜ cat test.hs main = putStrLn "Hello!" ➜ ghc --make -fforce-recomp -Wall ./test.hs [1 of 1] Compiling Main ( test.hs, test.o ) test.hs:1:1: Warning: Top-level binding with no type signature: main :: IO () Linking test ... }}} An example of a current error message: {{{ ➜ cat test2.hs main = foo ➜ ghc --make -fforce-recomp -Wall ./test2.hs [1 of 1] Compiling Main ( test2.hs, test2.o ) test2.hs:1:8: Not in scope: ‘foo’ }}} The proposal is to change the error message to become: {{{ ➜ cat test2.hs main = foo ➜ ghc --make -fforce-recomp -Wall ./test2.hs [1 of 1] Compiling Main ( test2.hs, test2.o ) test2.hs:1:8: Error: Not in scope: ‘foo’ }}} This change affects only the error messages produced by GHC when compiling. It does not change runtime error reporting, e.g. with the `error` function. == Motivation == We wish to make compile-time error messages easier for humans and computers to identify. For example, when running a long parallel build, it can be easy to miss an error message (see #9219 for an example). With a known string such as `Error:`, we can use search functionality in a terminal window or text editor (when viewing the build log) or use a command-line tool such as `grep` (when streaming and filtering the build log) to quickly find errors. As a secondary motivation, adding `Error:` for error messages brings a nice symmetry to the current use of `Warning:` for warning messages. == Disadvantages == The output of many regression tests will need to be updated for the new error message format. == Additional consideration == @hvr [comment:5 suggested] that during work on this bug we could make GHC output more consistent with other compilers (GCC and clang) by using lowercase `error:` and `warning:` prefixes. This might be potentially useful for existing tools that work on top of compiler output for finding errors/warning, and GHC's output will become "more valid" for them. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10021#comment:9 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler