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-rw-r--r--compiler/main/DynFlags.hs27
-rw-r--r--compiler/main/InteractiveEval.hs4
-rw-r--r--compiler/rename/RnBinds.hs2
-rw-r--r--compiler/rename/RnEnv.hs4
-rw-r--r--docs/users_guide/flags.xml26
-rw-r--r--docs/users_guide/using.xml63
-rw-r--r--testsuite/tests/rename/should_compile/T17a.hs18
-rw-r--r--testsuite/tests/rename/should_compile/T17a.stderr1
-rw-r--r--testsuite/tests/rename/should_compile/T17b.hs18
-rw-r--r--testsuite/tests/rename/should_compile/T17b.stderr1
-rw-r--r--testsuite/tests/rename/should_compile/T17c.hs18
-rw-r--r--testsuite/tests/rename/should_compile/T17c.stderr1
-rw-r--r--testsuite/tests/rename/should_compile/T17d.hs18
-rw-r--r--testsuite/tests/rename/should_compile/T17d.stderr1
-rw-r--r--testsuite/tests/rename/should_compile/T17e.hs18
-rw-r--r--testsuite/tests/rename/should_compile/T17e.stderr7
-rw-r--r--testsuite/tests/rename/should_compile/all.T6
-rw-r--r--testsuite/tests/rename/should_compile/rn040.hs16
18 files changed, 218 insertions, 31 deletions
diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index de768c0315..6d6670cb32 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -488,7 +488,9 @@ data WarningFlag =
| Opt_WarnOverlappingPatterns
| Opt_WarnTypeDefaults
| Opt_WarnMonomorphism
- | Opt_WarnUnusedBinds
+ | Opt_WarnUnusedTopBinds
+ | Opt_WarnUnusedLocalBinds
+ | Opt_WarnUnusedPatternBinds
| Opt_WarnUnusedImports
| Opt_WarnUnusedMatches
| Opt_WarnContextQuantification
@@ -2676,6 +2678,8 @@ dynamic_flags = [
, defFlag "fno-glasgow-exts"
(NoArg (do disableGlasgowExts
deprecate "Use individual extensions instead"))
+ , defFlag "fwarn-unused-binds" (NoArg enableUnusedBinds)
+ , defFlag "fno-warn-unused-binds" (NoArg disableUnusedBinds)
------ Safe Haskell flags -------------------------------------------
, defFlag "fpackage-trust" (NoArg setPackageTrust)
@@ -2883,10 +2887,12 @@ fWarningFlags = [
flagSpec "warn-unsupported-llvm-version" Opt_WarnUnsupportedLlvmVersion,
flagSpec "warn-unticked-promoted-constructors"
Opt_WarnUntickedPromotedConstructors,
- flagSpec "warn-unused-binds" Opt_WarnUnusedBinds,
flagSpec "warn-unused-do-bind" Opt_WarnUnusedDoBind,
flagSpec "warn-unused-imports" Opt_WarnUnusedImports,
+ flagSpec "warn-unused-local-binds" Opt_WarnUnusedLocalBinds,
flagSpec "warn-unused-matches" Opt_WarnUnusedMatches,
+ flagSpec "warn-unused-pattern-binds" Opt_WarnUnusedPatternBinds,
+ flagSpec "warn-unused-top-binds" Opt_WarnUnusedTopBinds,
flagSpec "warn-warnings-deprecations" Opt_WarnWarningsDeprecations,
flagSpec "warn-wrong-do-bind" Opt_WarnWrongDoBind]
@@ -3359,7 +3365,9 @@ minusWOpts :: [WarningFlag]
-- Things you get with -W
minusWOpts
= standardWarnings ++
- [ Opt_WarnUnusedBinds,
+ [ Opt_WarnUnusedTopBinds,
+ Opt_WarnUnusedLocalBinds,
+ Opt_WarnUnusedPatternBinds,
Opt_WarnUnusedMatches,
Opt_WarnUnusedImports,
Opt_WarnIncompletePatterns,
@@ -3381,6 +3389,19 @@ minusWallOpts
Opt_WarnUntickedPromotedConstructors
]
+enableUnusedBinds :: DynP ()
+enableUnusedBinds = mapM_ setWarningFlag unusedBindsFlags
+
+disableUnusedBinds :: DynP ()
+disableUnusedBinds = mapM_ unSetWarningFlag unusedBindsFlags
+
+-- Things you get with -fwarn-unused-binds
+unusedBindsFlags :: [WarningFlag]
+unusedBindsFlags = [ Opt_WarnUnusedTopBinds
+ , Opt_WarnUnusedLocalBinds
+ , Opt_WarnUnusedPatternBinds
+ ]
+
enableGlasgowExts :: DynP ()
enableGlasgowExts = do setGeneralFlag Opt_PrintExplicitForalls
mapM_ setExtensionFlag glasgowExtsFlags
diff --git a/compiler/main/InteractiveEval.hs b/compiler/main/InteractiveEval.hs
index 70c61f2215..ff588e1276 100644
--- a/compiler/main/InteractiveEval.hs
+++ b/compiler/main/InteractiveEval.hs
@@ -168,10 +168,10 @@ runStmtWithLocation source linenumber expr step =
breakMVar <- liftIO $ newEmptyMVar -- wait on this when we hit a breakpoint
statusMVar <- liftIO $ newEmptyMVar -- wait on this when a computation is running
- -- Turn off -fwarn-unused-bindings when running a statement, to hide
+ -- Turn off -fwarn-unused-local-binds when running a statement, to hide
-- warnings about the implicit bindings we introduce.
let ic = hsc_IC hsc_env -- use the interactive dflags
- idflags' = ic_dflags ic `wopt_unset` Opt_WarnUnusedBinds
+ idflags' = ic_dflags ic `wopt_unset` Opt_WarnUnusedLocalBinds
hsc_env' = hsc_env{ hsc_IC = ic{ ic_dflags = idflags' } }
-- compile to value (IO [HValue]), don't run
diff --git a/compiler/rename/RnBinds.hs b/compiler/rename/RnBinds.hs
index 89f8a14e6e..beda054423 100644
--- a/compiler/rename/RnBinds.hs
+++ b/compiler/rename/RnBinds.hs
@@ -497,7 +497,7 @@ rnBind _ bind@(PatBind { pat_lhs = pat
-- which (a) is not that different from _v = rhs
-- (b) is sometimes used to give a type sig for,
-- or an occurrence of, a variable on the RHS
- ; whenWOptM Opt_WarnUnusedBinds $
+ ; whenWOptM Opt_WarnUnusedPatternBinds $
when (null bndrs && not is_wild_pat) $
addWarn $ unusedPatBindWarn bind'
diff --git a/compiler/rename/RnEnv.hs b/compiler/rename/RnEnv.hs
index 580f0b9d3d..d9d471ace3 100644
--- a/compiler/rename/RnEnv.hs
+++ b/compiler/rename/RnEnv.hs
@@ -1734,7 +1734,7 @@ mapFvRnCPS f (x:xs) cont = f x $ \ x' ->
warnUnusedTopBinds :: [GlobalRdrElt] -> RnM ()
warnUnusedTopBinds gres
- = whenWOptM Opt_WarnUnusedBinds
+ = whenWOptM Opt_WarnUnusedTopBinds
$ do env <- getGblEnv
let isBoot = tcg_src env == HsBootFile
let noParent gre = case gre_par gre of
@@ -1751,7 +1751,7 @@ warnUnusedTopBinds gres
warnUnusedGREs gres'
warnUnusedLocalBinds, warnUnusedMatches :: [Name] -> FreeVars -> RnM ()
-warnUnusedLocalBinds = check_unused Opt_WarnUnusedBinds
+warnUnusedLocalBinds = check_unused Opt_WarnUnusedLocalBinds
warnUnusedMatches = check_unused Opt_WarnUnusedMatches
check_unused :: WarningFlag -> [Name] -> FreeVars -> RnM ()
diff --git a/docs/users_guide/flags.xml b/docs/users_guide/flags.xml
index 98c09bf322..3d90479adf 100644
--- a/docs/users_guide/flags.xml
+++ b/docs/users_guide/flags.xml
@@ -1578,12 +1578,36 @@
<row>
<entry><option>-fwarn-unused-binds</option></entry>
- <entry>warn about bindings that are unused</entry>
+ <entry>warn about bindings that are unused.
+ Alias for <option>-fwarn-unused-top-binds</option>,
+ <option>-fwarn-unused-local-binds</option> and
+ <option>-fwarn-unused-pattern-binds</option></entry>
<entry>dynamic</entry>
<entry><option>-fno-warn-unused-binds</option></entry>
</row>
<row>
+ <entry><option>-fwarn-unused-top-binds</option></entry>
+ <entry>warn about top-level bindings that are unused</entry>
+ <entry>dynamic</entry>
+ <entry><option>-fno-warn-unused-top-binds</option></entry>
+ </row>
+
+ <row>
+ <entry><option>-fwarn-unused-local-binds</option></entry>
+ <entry>warn about local bindings that are unused</entry>
+ <entry>dynamic</entry>
+ <entry><option>-fno-warn-unused-local-binds</option></entry>
+ </row>
+
+ <row>
+ <entry><option>-fwarn-unused-pattern-binds</option></entry>
+ <entry>warn about pattern match bindings that are unused</entry>
+ <entry>dynamic</entry>
+ <entry><option>-fno-warn-unused-pattern-binds</option></entry>
+ </row>
+
+ <row>
<entry><option>-fwarn-unused-imports</option></entry>
<entry>warn about unnecessary imports</entry>
<entry>dynamic</entry>
diff --git a/docs/users_guide/using.xml b/docs/users_guide/using.xml
index 1940e7abc4..19839cf6fb 100644
--- a/docs/users_guide/using.xml
+++ b/docs/users_guide/using.xml
@@ -1872,33 +1872,71 @@ data Vec n s where
<indexterm><primary><option>-fwarn-unused-binds</option></primary></indexterm>
<indexterm><primary>unused binds, warning</primary></indexterm>
<indexterm><primary>binds, unused</primary></indexterm>
- <para>Report any function definitions (and local bindings)
- which are unused. More precisely:
+ <para>Report any function definitions (and local bindings) which are unused. An alias for
+ <itemizedlist>
+ <listitem><option>-fwarn-unused-top-binds</option></listitem>
+ <listitem><option>-fwarn-unused-local-binds</option></listitem>
+ <listitem><option>-fwarn-unused-pattern-binds</option></listitem>
+ </itemizedlist>
+ </para>
+ </listitem>
+ </varlistentry>
- <itemizedlist>
- <listitem><para>Warn if a binding brings into scope a variable that is not used,
+ <varlistentry>
+ <term><option>-fwarn-unused-top-binds</option>:</term>
+ <listitem>
+ <indexterm><primary><option>-fwarn-unused-top-binds</option></primary></indexterm>
+ <indexterm><primary>unused binds, warning</primary></indexterm>
+ <indexterm><primary>binds, unused</primary></indexterm>
+ <para>Report any function definitions which are unused.</para>
+
+ <para>More precisely, warn if a binding brings into scope a variable that is not used,
except if the variable's name starts with an underscore. The "starts-with-underscore"
condition provides a way to selectively disable the warning.
- </para>
+ </para>
<para>
- A variable is regarded as "used" if
+ A variable is regarded as "used" if
<itemizedlist>
<listitem><para>It is exported, or</para></listitem>
- <listitem><para>It appears in the right hand side of a binding that binds at
+ <listitem><para>It appears in the right hand side of a binding that binds at
least one used variable that is used</para></listitem>
</itemizedlist>
For example
<programlisting>
module A (f) where
-f = let (p,q) = rhs1 in t p -- Warning about unused q
+f = let (p,q) = rhs1 in t p -- No warning: q is unused, but is locally bound
t = rhs3 -- No warning: f is used, and hence so is t
g = h x -- Warning: g unused
h = rhs2 -- Warning: h is only used in the right-hand side of another unused binding
_w = True -- No warning: _w starts with an underscore
</programlisting>
- </para></listitem>
+ </para>
+ </listitem>
+ </varlistentry>
- <listitem><para>
+ <varlistentry>
+ <term><option>-fwarn-unused-local-binds</option>:</term>
+ <listitem>
+ <indexterm><primary><option>-fwarn-unused-local-binds</option></primary></indexterm>
+ <indexterm><primary>unused binds, warning</primary></indexterm>
+ <indexterm><primary>binds, unused</primary></indexterm>
+ <para>Report any local definitions which are unused. For example
+ <programlisting>
+module A (f) where
+f = let (p,q) = rhs1 in t p -- Warning: q is unused
+g = h x -- No warning: g is unused, but is a top-level binding
+ </programlisting>
+ </para>
+ </listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><option>-fwarn-unused-pattern-binds</option>:</term>
+ <listitem>
+ <indexterm><primary><option>-fwarn-unused-pattern-binds</option></primary></indexterm>
+ <indexterm><primary>unused binds, warning</primary></indexterm>
+ <indexterm><primary>binds, unused</primary></indexterm>
+ <para>
Warn if a pattern binding binds no variables at all, unless it is a lone, possibly-banged, wild-card pattern.
For example:
<programlisting>
@@ -1911,13 +1949,10 @@ _ = rhs3 -- No warning: lone wild-card pattern
are not very different from <literal>_v = rhs3</literal>,
which elicits no warning; and they can be useful to add a type
constraint, e.g. <literal>_ = x::Int</literal>. A lone
- banged wild-card pattern is is useful as an alternative
+ banged wild-card pattern is useful as an alternative
(to <literal>seq</literal>) way to force evaluation.
</para>
</listitem>
- </itemizedlist>
- </para>
- </listitem>
</varlistentry>
<varlistentry>
diff --git a/testsuite/tests/rename/should_compile/T17a.hs b/testsuite/tests/rename/should_compile/T17a.hs
new file mode 100644
index 0000000000..a58a766340
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17a.hs
@@ -0,0 +1,18 @@
+{-# OPTIONS_GHC -fwarn-unused-top-binds #-}
+
+-- Trac #17
+
+module Temp (foo, bar, quux) where
+
+top :: Int
+top = 1
+
+foo :: ()
+foo = let True = True in ()
+
+bar :: Int -> Int
+bar match = 1
+
+quux :: Int
+quux = let local = True
+ in 2
diff --git a/testsuite/tests/rename/should_compile/T17a.stderr b/testsuite/tests/rename/should_compile/T17a.stderr
new file mode 100644
index 0000000000..308cabe23c
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17a.stderr
@@ -0,0 +1 @@
+ T17a.hs:8:1: Warning: Defined but not used: ‘top’ \ No newline at end of file
diff --git a/testsuite/tests/rename/should_compile/T17b.hs b/testsuite/tests/rename/should_compile/T17b.hs
new file mode 100644
index 0000000000..7946f16deb
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17b.hs
@@ -0,0 +1,18 @@
+{-# OPTIONS_GHC -fwarn-unused-local-binds #-}
+
+-- Trac #17
+
+module Temp (foo, bar, quux) where
+
+top :: Int
+top = 1
+
+foo :: ()
+foo = let True = True in ()
+
+bar :: Int -> Int
+bar match = 1
+
+quux :: Int
+quux = let local = True
+ in 2
diff --git a/testsuite/tests/rename/should_compile/T17b.stderr b/testsuite/tests/rename/should_compile/T17b.stderr
new file mode 100644
index 0000000000..3291264463
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17b.stderr
@@ -0,0 +1 @@
+ T17b.hs:17:12: Warning: Defined but not used: ‘local’ \ No newline at end of file
diff --git a/testsuite/tests/rename/should_compile/T17c.hs b/testsuite/tests/rename/should_compile/T17c.hs
new file mode 100644
index 0000000000..091524c95a
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17c.hs
@@ -0,0 +1,18 @@
+{-# OPTIONS_GHC -fwarn-unused-pattern-binds #-}
+
+-- Trac #17
+
+module Temp (foo, bar, quux) where
+
+top :: Int
+top = 1
+
+foo :: ()
+foo = let True = True in ()
+
+bar :: Int -> Int
+bar match = 1
+
+quux :: Int
+quux = let local = True
+ in 2
diff --git a/testsuite/tests/rename/should_compile/T17c.stderr b/testsuite/tests/rename/should_compile/T17c.stderr
new file mode 100644
index 0000000000..bfab9f83da
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17c.stderr
@@ -0,0 +1 @@
+ T17c.hs:11:11: Warning: This pattern-binding binds no variables: True = True \ No newline at end of file
diff --git a/testsuite/tests/rename/should_compile/T17d.hs b/testsuite/tests/rename/should_compile/T17d.hs
new file mode 100644
index 0000000000..1a4b44d717
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17d.hs
@@ -0,0 +1,18 @@
+{-# OPTIONS_GHC -fwarn-unused-matches #-}
+
+-- Trac #17
+
+module Temp (foo, bar, quux) where
+
+top :: Int
+top = 1
+
+foo :: ()
+foo = let True = True in ()
+
+bar :: Int -> Int
+bar match = 1
+
+quux :: Int
+quux = let local = True
+ in 2
diff --git a/testsuite/tests/rename/should_compile/T17d.stderr b/testsuite/tests/rename/should_compile/T17d.stderr
new file mode 100644
index 0000000000..babe6b780e
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17d.stderr
@@ -0,0 +1 @@
+ T17d.hs:14:5: Warning: Defined but not used: ‘match’ \ No newline at end of file
diff --git a/testsuite/tests/rename/should_compile/T17e.hs b/testsuite/tests/rename/should_compile/T17e.hs
new file mode 100644
index 0000000000..93ed1f7344
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17e.hs
@@ -0,0 +1,18 @@
+{-# OPTIONS_GHC -fwarn-unused-binds #-}
+
+-- Trac #17
+
+module Temp (foo, bar, quux) where
+
+top :: Int
+top = 1
+
+foo :: ()
+foo = let True = True in ()
+
+bar :: Int -> Int
+bar match = 1
+
+quux :: Int
+quux = let local = True
+ in 2
diff --git a/testsuite/tests/rename/should_compile/T17e.stderr b/testsuite/tests/rename/should_compile/T17e.stderr
new file mode 100644
index 0000000000..48f28b8db4
--- /dev/null
+++ b/testsuite/tests/rename/should_compile/T17e.stderr
@@ -0,0 +1,7 @@
+
+T17e.hs:8:1: Warning: Defined but not used: ‘top’
+
+T17e.hs:11:11: Warning:
+ This pattern-binding binds no variables: True = True
+
+T17e.hs:17:12: Warning: Defined but not used: ‘local’
diff --git a/testsuite/tests/rename/should_compile/all.T b/testsuite/tests/rename/should_compile/all.T
index 9265f18a61..0747f98ced 100644
--- a/testsuite/tests/rename/should_compile/all.T
+++ b/testsuite/tests/rename/should_compile/all.T
@@ -112,6 +112,12 @@ test('rn067',
test('rn068', normal, compile, [''])
+test('T17a', normal, compile, [''])
+test('T17b', normal, compile, [''])
+test('T17c', normal, compile, [''])
+test('T17d', normal, compile, [''])
+test('T17e', normal, compile, [''])
+
test('T1972', normal, compile, [''])
test('T2205', normal, compile, [''])
diff --git a/testsuite/tests/rename/should_compile/rn040.hs b/testsuite/tests/rename/should_compile/rn040.hs
index 3b418f5c2f..3a74abe3fd 100644
--- a/testsuite/tests/rename/should_compile/rn040.hs
+++ b/testsuite/tests/rename/should_compile/rn040.hs
@@ -1,8 +1,8 @@
-{-# OPTIONS -fwarn-unused-binds #-}
-module ShouldCompile where
-
--- !!! should produce warnings about unused identifers
-x :: [()]
-x = [ () | y <- [] ]
-
-z = do w <- getContents; return ()
+{-# OPTIONS -fwarn-unused-binds #-}
+module ShouldCompile where
+
+-- !!! should produce warnings about unused identifers
+x :: [()]
+x = [ () | y <- [] ]
+
+z = do w <- getContents; return ()
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