haskell - stack setup 7.10.3 only installs 7.10.2 -

can explain why stack setup 7.10.3 installs 7.10.2?

john@john-3-11:~$ stack setup 7.10.3 downloaded.                  installed ghc.      add following path: /home/john/.stack/programs/x86_64-linux/ghc-7.10.2/bin john@john-3-11:~$ ls /home/john/.stack/programs/x86_64-linux/ ghc-7.10.2  ghc-7.10.2.installed  ghc-7.10.2.tar.xz 

this issue because trying install ihaskell:

john@john-3-11:~$ stack install ihaskell-0.8.3.0 using resolver: lts-5.0 global config file: /home/john/.stack/global/stack.yaml ghc version mismatched, found 7.10.2 (x86_64), expected version 7.10.3 (x86_64) (based on resolver setting in /home/john/.stack/global/stack.yaml). try running stack setup 

i installed 7.10.3 way... , it's located in different part of computer /opt/ghc/7.10.3 there 2 different versionf of ghc floating around. , further confusion, which points version installed in stack:

john@john-lenovo-yoga-3-11:~$ ghc /home/john/.stack/programs/x86_64-linux/ghc-7.10.2/bin/ghc 

why can't stack install 7.10.3 in first place? @ least tell stack put it.

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$ stack setup -v version 0.1.2.0 2016-01-27 21:31:16.546277: [debug] checking project config at: /home/john/stack.yaml @(stack-0.1.2.0:stack.config src/stack/config.hs:496:9) 2016-01-27 21:31:16.546422: [debug] checking project config at: /home/stack.yaml @(stack-0.1.2.0:stack.config src/stack/config.hs:496:9) 2016-01-27 21:31:16.546482: [debug] checking project config at: /stack.yaml @(stack-0.1.2.0:stack.config src/stack/config.hs:496:9) 2016-01-27 21:31:16.546533: [debug] no project config file found, using defaults. @(stack-0.1.2.0:stack.config src/stack/config.hs:523:13) 2016-01-27 21:31:16.547163: [info] using resolver: lts-5.0 global config file: /home/john/.stack/global/stack.yaml @(stack-0.1.2.0:stack.config src/stack/config.hs:302:32) 2016-01-27 21:31:16.557306: [debug] run process: ghc --info @(stack-0.1.2.0:system.process.read src/system/process/read.hs:254:3) 2016-01-27 21:31:16.594867: [debug] performing sanity check on: /usr/bin/ghc @(stack-0.1.2.0:stack.setup src/stack/setup.hs:754:5) 2016-01-27 21:31:16.595008: [debug] run process: ghc /tmp/stack-sanity-check11387/main.hs -no-user-package-db @(stack-0.1.2.0:system.process.read src/system/process/read.hs:254:3) 2016-01-27 21:31:16.905181: [info] ghc on path used @(main:main src/main/main.hs:439:30)