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copied!<p>The issue is the same as discussed below, the flags changed:</p> <pre class="lang-none prettyprint-override"><code>~/.../Util> ghc Other.hs [1 of 1] Compiling Util.Other ( Other.hs, Other.o ) ~/.../Util> cd .. ~/.../src> ghc MyFile.hs [1 of 2] Compiling Util.Other ( Util/Other.hs, Util/Other.o ) [flags changed] [2 of 2] Compiling MyFile ( MyFile.hs, MyFile.o ) </code></pre> <p>I haven't found out which flags in particular, or why the flags passed during separate compilation are different than the ones that are passed when compiling as a module chased from the importing module, but they do change, and hence a recompilation is necessary (Specifically, the flag-hash value in the <code>.hi</code> file changes).</p> <p>The fix is therefore to not compile the modules separately, but to compile them as dependencies of the top-level importer.</p> <hr> <p>Original almost correct guesswork:</p> <p>I can only partly reproduce that. After compiling and then <code>touch</code>ing <code>MyFile.hs</code>,</p> <pre class="lang-none prettyprint-override"><code>$ ghci-7.4.2 MyFile.hs -- snip [1 of 2] Compiling Util.Other ( Util/Other.hs, interpreted ) [2 of 2] Compiling MyFile ( MyFile.hs, interpreted ) Ok, modules loaded: MyFile, Util.Other. </code></pre> <p>it looks the same as for you, but with 7.6.1, we get a hint (compiling and <code>touch</code>ing):</p> <pre class="lang-none prettyprint-override"><code>$ ghci MyFile.hs -- snip [1 of 2] Compiling Util.Other ( Util/Other.hs, interpreted ) [flags changed] [2 of 2] Compiling MyFile ( MyFile.hs, interpreted ) Ok, modules loaded: MyFile, Util.Other. </code></pre> <p>The flags changed. I have <code>:set -XNoMonomorphismRestriction</code> in my <code>.ghci</code> file, and the change of flags causes the recompilation.</p> <pre class="lang-none prettyprint-override"><code>$ ghci -ignore-dot-ghci MyFile.hs GHCi, version 7.6.1: http://www.haskell.org/ghc/ :? for help Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. [2 of 2] Compiling MyFile ( MyFile.hs, interpreted ) Ok, modules loaded: MyFile, Util.Other. </code></pre> <p>Ignoring the offending <code>.ghci</code> with the flag that wasn't given for the compilation, the unchanged <code>Util.Other</code> is not interpreted, the compiled code is used. (With GHC < 7.4, ignoring the <code>.ghci</code> file isn't even necessary.)</p> <p>If you have a <code>.ghci</code> file in which you set language options (<code>NoMonomorphismRestriction</code>, <code>TypeFamilies</code>, ...) and ghc >= 7.4, you need to ignore the <code>.ghci</code> file when loading the modules.</p> <p>If that is not the case, the recompilation is not the expected behaviour. Then more information would be necessary to diagnose the problem and find a fix.</p> <p>A semi-work-around would then be the <code>-fobject-code</code> flag for ghci.</p>

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