Issue #6257 has been updated by jonforums (Jon Forums). ruby_1_9_3 now builds and passes `make test` using clang 3.1 (trunk 154297) + MinGW 4.6.2 on Win7 32bit :) ---------------------------------------- Backport #6257: [mingw] -Wshorten-64-to-32 error in io.c using clang https://bugs.ruby-lang.org/issues/6257#change-25732 Author: jonforums (Jon Forums) Status: Closed Priority: Normal Assignee: Category: Target version: Building trunk@35349 on Win7 32bit with clang 3.1 (trunk build on Win7) + MinGW GCC 4.6.2 I get the following error: C:\Users\Jon\Documents\RubyDev\ruby-git\build>sh -c "../configure --enable-shared --disable-install-doc --with-gcc=c:/clang/bin/clang.exe" C:\Users\Jon\Documents\RubyDev\ruby-git\build>make ... compiling ../io.c ../io.c:458:21: error: implicit conversion loses integer precision: 'long long' to 'long' [-Werror,-Wshorten-64-to-32] extra_max = pos - fptr->rbuf.len; ~ ~~~~^~~~~~~~~~~~~~~~ 1 error generated. make: *** [io.o] Error 1 -- http://bugs.ruby-lang.org/