diff --git a/Cabal/Distribution/Compat/Prelude.hs b/Cabal/Distribution/Compat/Prelude.hs
index 21eec8d2217..0242c438d37 100644
--- a/Cabal/Distribution/Compat/Prelude.hs
+++ b/Cabal/Distribution/Compat/Prelude.hs
@@ -40,6 +40,7 @@ module Distribution.Compat.Prelude (
     Binary (..),
     Alternative (..),
     MonadPlus (..),
+    IsString (..),
 
     -- * Some types
     IO, NoCallStackIO,
@@ -131,6 +132,7 @@ import Data.List                     (intercalate, intersperse, isPrefixOf,
                                       isSuffixOf, nub, nubBy, sort, sortBy,
                                       unfoldr)
 import Data.Maybe
+import Data.String                   (IsString (..))
 import Data.Int
 import Data.Word
 
diff --git a/Cabal/Distribution/ModuleName.hs b/Cabal/Distribution/ModuleName.hs
index 1fa1435b532..ffb60f34d60 100644
--- a/Cabal/Distribution/ModuleName.hs
+++ b/Cabal/Distribution/ModuleName.hs
@@ -76,12 +76,12 @@ simple str = ModuleName (stlFromStrings [str])
 -- an error if it is used with a string that is not a valid module name. If you
 -- are parsing user input then use 'Distribution.Text.simpleParse' instead.
 --
-fromString :: String -> ModuleName
-fromString string = fromComponents (split string)
-  where
-    split cs = case break (=='.') cs of
-      (chunk,[])     -> chunk : []
-      (chunk,_:rest) -> chunk : split rest
+instance IsString ModuleName where
+    fromString string = fromComponents (split string)
+      where
+        split cs = case break (=='.') cs of
+          (chunk,[])     -> chunk : []
+          (chunk,_:rest) -> chunk : split rest
 
 -- | Construct a 'ModuleName' from valid module components, i.e. parts
 -- separated by dots.
diff --git a/Cabal/Distribution/Package.hs b/Cabal/Distribution/Package.hs
index 899f0ec0842..6c9682b68cf 100644
--- a/Cabal/Distribution/Package.hs
+++ b/Cabal/Distribution/Package.hs
@@ -89,6 +89,12 @@ unPackageName (PackageName s) = fromShortText s
 mkPackageName :: String -> PackageName
 mkPackageName = PackageName . toShortText
 
+-- | 'mkPackageName'
+--
+-- @since 2.0
+instance IsString PackageName where
+  fromString = mkPackageName
+
 instance Binary PackageName
 
 instance Text PackageName where
@@ -123,6 +129,12 @@ unPkgconfigName (PkgconfigName s) = fromShortText s
 mkPkgconfigName :: String -> PkgconfigName
 mkPkgconfigName = PkgconfigName . toShortText
 
+-- | 'mkPkgconfigName'
+--
+-- @since 2.0
+instance IsString PkgconfigName where
+    fromString = mkPkgconfigName
+
 instance Binary PkgconfigName
 
 -- pkg-config allows versions and other letters in package names, eg
@@ -215,6 +227,12 @@ newtype ComponentId = ComponentId ShortText
 mkComponentId :: String -> ComponentId
 mkComponentId = ComponentId . toShortText
 
+-- | 'mkComponentId'
+--
+-- @since 2.0
+instance IsString ComponentId where
+    fromString = mkComponentId
+
 -- | Convert 'ComponentId' to 'String'
 --
 -- @since 2.0
@@ -288,15 +306,21 @@ instance Text UnitId where
     disp = text . unUnitId
     parse = mkUnitId <$> Parse.munch1 (\c -> isAlphaNum c || c `elem` "-_.+")
 
-unUnitId :: UnitId -> String
-unUnitId (UnitId s) = fromShortText s
-
 -- | If you need backwards compatibility, consider using 'display'
 -- instead, which is supported by all versions of Cabal.
 --
+unUnitId :: UnitId -> String
+unUnitId (UnitId s) = fromShortText s
+
 mkUnitId :: String -> UnitId
 mkUnitId = UnitId . toShortText
 
+-- | 'mkUnitId'
+--
+-- @since 2.0
+instance IsString UnitId where
+    fromString = mkUnitId
+
 -- | A 'UnitId' for a definite package.  The 'DefUnitId' invariant says
 -- that a 'UnitId' identified this way is definite; i.e., it has no
 -- unfilled holes.
@@ -388,6 +412,12 @@ unAbiHash (AbiHash h) = fromShortText h
 mkAbiHash :: String -> AbiHash
 mkAbiHash = AbiHash . toShortText
 
+-- | 'mkAbiHash'
+--
+-- @since 2.0
+instance IsString AbiHash where
+    fromString = mkAbiHash
+
 instance Binary AbiHash
 
 instance Text AbiHash where
diff --git a/Cabal/Distribution/Types/GenericPackageDescription.hs b/Cabal/Distribution/Types/GenericPackageDescription.hs
index 4e9d82e831a..01d9936dedc 100644
--- a/Cabal/Distribution/Types/GenericPackageDescription.hs
+++ b/Cabal/Distribution/Types/GenericPackageDescription.hs
@@ -102,6 +102,12 @@ newtype FlagName = FlagName ShortText
 mkFlagName :: String -> FlagName
 mkFlagName = FlagName . toShortText
 
+-- | 'mkFlagName'
+--
+-- @since 2.0
+instance IsString FlagName where
+    fromString = mkFlagName
+
 -- | Convert 'FlagName' to 'String'
 --
 -- @since 2.0
diff --git a/Cabal/Distribution/Types/UnqualComponentName.hs b/Cabal/Distribution/Types/UnqualComponentName.hs
index 3ead6f5f1b1..1996ff0997e 100644
--- a/Cabal/Distribution/Types/UnqualComponentName.hs
+++ b/Cabal/Distribution/Types/UnqualComponentName.hs
@@ -44,6 +44,12 @@ unUnqualComponentName (UnqualComponentName s) = fromShortText s
 mkUnqualComponentName :: String -> UnqualComponentName
 mkUnqualComponentName = UnqualComponentName . toShortText
 
+-- | 'mkUnqualComponentName'
+--
+-- @since 2.0
+instance IsString UnqualComponentName where
+  fromString = mkUnqualComponentName
+
 instance Binary UnqualComponentName
 
 instance Text UnqualComponentName where
diff --git a/Cabal/Distribution/Utils/ShortText.hs b/Cabal/Distribution/Utils/ShortText.hs
index bc413e05d4c..dd2f594b3a5 100644
--- a/Cabal/Distribution/Utils/ShortText.hs
+++ b/Cabal/Distribution/Utils/ShortText.hs
@@ -17,8 +17,6 @@ import Prelude ()
 import Distribution.Compat.Prelude
 import Distribution.Utils.String
 
-import Data.String (IsString(..))
-
 #if defined(MIN_VERSION_bytestring)
 # if MIN_VERSION_bytestring(0,10,4)
 # define HAVE_SHORTBYTESTRING 1
diff --git a/cabal-install/Distribution/Client/Init.hs b/cabal-install/Distribution/Client/Init.hs
index 3b7bf9b9f3c..e06a689bb1f 100644
--- a/cabal-install/Distribution/Client/Init.hs
+++ b/cabal-install/Distribution/Client/Init.hs
@@ -53,7 +53,7 @@ import Distribution.Version
 import Distribution.Verbosity
   ( Verbosity )
 import Distribution.ModuleName
-  ( ModuleName, fromString )  -- And for the Text instance
+  ( ModuleName )  -- And for the Text instance
 import Distribution.InstalledPackageInfo
   ( InstalledPackageInfo, sourcePackageId, exposed )
 import qualified Distribution.Package as P
diff --git a/cabal-testsuite/cabal-testsuite.cabal b/cabal-testsuite/cabal-testsuite.cabal
index 94a350596ec..da23e1af700 100644
--- a/cabal-testsuite/cabal-testsuite.cabal
+++ b/cabal-testsuite/cabal-testsuite.cabal
@@ -32,13 +32,13 @@ library
     Test.Cabal.Server
     Test.Cabal.Monad
   build-depends:
-    aeson,
+    aeson == 1.1.*,
     attoparsec,
     async,
     base,
     bytestring,
     transformers,
-    optparse-applicative,
+    optparse-applicative ==0.12.*,
     process,
     directory,
     filepath,
diff --git a/stack.yaml b/stack.yaml
index 9fd01beda5c..b3d801a9640 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -40,7 +40,7 @@ extra-deps:
 - stm-2.4.4.1
 - tagged-0.8.4
 - tar-0.5.0.3
-- tasty-0.11.0.3
+- tasty-0.11.0.4
 - tasty-hunit-0.9.2
 - tasty-quickcheck-0.8.4
 - text-1.2.2.1