target "is not a module name or a source file"

Create a standalone Haskell program "/tmp/delme.hs". Then do

$ cd /tmp
{- 0 -}$ ghc --make -o delme.exe /tmp/delme.hs
[1 of 1] Compiling Main ( /tmp/delme.hs, /tmp/delme.o )
Linking delme.exe ...
$ rm delme.o
{- 1 -}$ ghc --make -o delme.exe /tmp/delme
[1 of 1] Compiling Main ( /tmp/delme.hs, /tmp/delme.o )
Linking delme.exe ...
$ rm delme.o
$ mv delme.hs delme
{- 2 -}$ ghc --make -o delme.exe /tmp/delme
target `/tmp/delme' is not a module name or a source file

We see that:[[BR]]

• in "1" GHC compiles "/tmp/delme.hs" though I say "/tmp/delme";[[BR]]
• in "2" GHC can not see file "/tmp/delme".

The problem is that a target (the last argument) may be a module name or a source file. GHC uses heuristics to determine this. Though heuristics may seem neat and clever, they draw GHC more intricate and unpredictable (see also KISS).

I encountered this intricacy when ran "ghc" on a shell script. Shell scripts in Unix commonly do not have extensions, because interpreter name is included in a shell script. And "runghc" runs them fine. "ghc" in theory also does not require a file to have an extension because it clearly contains Haskell source code — what else?

I propose to introduce a GHC flag which says explicitly which type a target is of.

Trac metadata

Trac field	Value
Version	6.12.2
Type	FeatureRequest
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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