.tix file generation broken with -fhpc and --make flags with lhs modules

Assume the project consisting of two files: Main.lhs and MyModule.hs. Main.lhs imports MyModule via standard import. Build the project with

ghc --make -fhpc -o main Main.lhs

The generated .tix file contains relevant information and hpc markup correctly shows the coverage for MyModule.

Now rename MyModule.hs to MyModule.lhs and enclose the code there in \begin{code} / \end{code}. Build again. The compilation still succeeds and the executable works fine. But main.tix now seems wrong and no hpc coverage information is available for MyModule