Warn on all out-of-range literals in pats/exprs

Summary:
These changes were motivated by #13256. While poking around, I
realized we weren't very consistent in our "-Woverflowed-literals"
warnings. This patch fixes that by:

  * warning earlier on in the pipeline (ie. before we've desugared
    'Int' patterns into 'I# Int#')
  * handling 'HsLit' as well as 'HsOverLit' (this covers unboxed
    literals)
  * covering more pattern / expression forms

4/6 of the warnings in the 'Overflow' test are due to this patch. The
other two are mostly for completeness.

Also fixed a missing empty-enumeration warning for 'Natural'.

This warnings were tripped up by the 'Bounded Word' instance (see #9505),
but the fix was obvious and simple: use unboxed word literals.

Test Plan: make TEST=Overflow && make TEST=T10930

Reviewers: hvr, bgamari, RyanGlScott

Reviewed By: RyanGlScott

Subscribers: RyanGlScott, rwbarton, carter

GHC Trac Issues: #13256, #10930

Differential Revision: https://phabricator.haskell.org/D5181

11 files changed, 119 insertions, 1 deletions

diff --git a/testsuite/tests/warnings/should_compile/Overflow.hs b/testsuite/tests/warnings/should_compile/Overflow.hs
new file mode 100644
index 0000000000..7029b7aaa8
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/Overflow.hs
@@ -0,0 +1,32 @@
+{-# LANGUAGE MagicHash #-}
+module Overflow where
+
+import GHC.Exts
+
+-- Overflow an 'Int#' expression
+f x = let y :: Int#
+          y = 10000000000000000000000000000000#
+      in 9
+
+-- Overflow an 'Int#' pattern
+g :: Int# -> Bool
+g 100000000000000000000000000# = True
+g _ = False
+
+-- Overflow an 'Int' expression
+h :: Int
+h = 1000000000000000000000000000000
+
+-- Overflow an 'Int' pattern
+i :: Int -> Int
+i 100000000000000000000000000000000 = 0
+i _ = 1
+
+-- Underflow a 'Word' expression
+j :: Word
+j = -1
+
+-- Underflow a 'Word' pattern
+k :: Word -> Bool
+k (-1) = True
+k _ = False
diff --git a/testsuite/tests/warnings/should_compile/Overflow.stderr b/testsuite/tests/warnings/should_compile/Overflow.stderr
new file mode 100644
index 0000000000..ce657aebf6
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/Overflow.stderr
@@ -0,0 +1,18 @@
+
+Overflow.hs:8:15: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal 10000000000000000000000000000000 is out of the Int# range -9223372036854775808..9223372036854775807
+
+Overflow.hs:13:1: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal 100000000000000000000000000 is out of the Int# range -9223372036854775808..9223372036854775807
+
+Overflow.hs:18:5: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal 1000000000000000000000000000000 is out of the Int range -9223372036854775808..9223372036854775807
+
+Overflow.hs:22:1: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal 100000000000000000000000000000000 is out of the Int range -9223372036854775808..9223372036854775807
+
+Overflow.hs:27:6: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -1 is out of the Word range 0..18446744073709551615
+
+Overflow.hs:31:1: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -1 is out of the Word range 0..18446744073709551615
diff --git a/testsuite/tests/warnings/should_compile/T10930.hs b/testsuite/tests/warnings/should_compile/T10930.hs
new file mode 100644
index 0000000000..e7a60952cf
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T10930.hs
@@ -0,0 +1,10 @@
+{-# LANGUAGE NegativeLiterals #-}
+module T10930 where
+
+import Numeric.Natural
+
+x = -123 :: Word
+y = -123 :: Natural
+
+w = [10..3] :: [Word]
+z = [10..3] :: [Natural]
diff --git a/testsuite/tests/warnings/should_compile/T10930.stderr b/testsuite/tests/warnings/should_compile/T10930.stderr
new file mode 100644
index 0000000000..1b593b9f38
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T10930.stderr
@@ -0,0 +1,11 @@
+
+T10930.hs:6:5: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -123 is out of the Word range 0..18446744073709551615
+
+T10930.hs:7:5: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -123 is negative but Natural only supports positive numbers
+
+T10930.hs:9:5: warning: [-Wempty-enumerations (in -Wdefault)] Enumeration is empty
+
+T10930.hs:10:5: warning: [-Wempty-enumerations (in -Wdefault)]
+    Enumeration is empty
diff --git a/testsuite/tests/warnings/should_compile/T10930b.hs b/testsuite/tests/warnings/should_compile/T10930b.hs
new file mode 100644
index 0000000000..59441669c2
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T10930b.hs
@@ -0,0 +1,7 @@
+{-# LANGUAGE NegativeLiterals #-}
+module T10930a where
+
+import Numeric.Natural
+
+x = [-10 .. -3] :: [Natural]
+y = [-3 .. -10] :: [Natural]
diff --git a/testsuite/tests/warnings/should_compile/T10930b.stderr b/testsuite/tests/warnings/should_compile/T10930b.stderr
new file mode 100644
index 0000000000..a967efa839
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T10930b.stderr
@@ -0,0 +1,15 @@
+
+T10930b.hs:6:6: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -10 is negative but Natural only supports positive numbers
+
+T10930b.hs:6:13: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -3 is negative but Natural only supports positive numbers
+
+T10930b.hs:7:5: warning: [-Wempty-enumerations (in -Wdefault)]
+    Enumeration is empty
+
+T10930b.hs:7:6: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -3 is negative but Natural only supports positive numbers
+
+T10930b.hs:7:12: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal -10 is negative but Natural only supports positive numbers
diff --git a/testsuite/tests/warnings/should_compile/T13256.hs b/testsuite/tests/warnings/should_compile/T13256.hs
new file mode 100644
index 0000000000..f02886331d
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T13256.hs
@@ -0,0 +1,4 @@
+module T13256 where
+
+v :: Int
+v = (\x -> case (x :: Int) of 100000000000000000000000000000000 -> 0) 8 :: Int
diff --git a/testsuite/tests/warnings/should_compile/T13256.stderr b/testsuite/tests/warnings/should_compile/T13256.stderr
new file mode 100644
index 0000000000..6b06a7d093
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T13256.stderr
@@ -0,0 +1,3 @@
+
+T13256.hs:4:12: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal 100000000000000000000000000000000 is out of the Int range -9223372036854775808..9223372036854775807
diff --git a/testsuite/tests/warnings/should_compile/T15460.hs b/testsuite/tests/warnings/should_compile/T15460.hs
new file mode 100644
index 0000000000..369acd8f35
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T15460.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE MagicHash #-}
+module T15460 where
+
+import GHC.Int
+
+main :: IO ()
+main = do
+   let x = I# (0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff#)
+   print x
diff --git a/testsuite/tests/warnings/should_compile/T15460.stderr b/testsuite/tests/warnings/should_compile/T15460.stderr
new file mode 100644
index 0000000000..5907b44320
--- /dev/null
+++ b/testsuite/tests/warnings/should_compile/T15460.stderr
@@ -0,0 +1,3 @@
+
+T15460.hs:8:16: warning: [-Woverflowed-literals (in -Wdefault)]
+    Literal 7237005577332262213973186563042994240829374041602535252466099000494570602495 is out of the GHC.Prim.Int# range -9223372036854775808..9223372036854775807
diff --git a/testsuite/tests/warnings/should_compile/all.T b/testsuite/tests/warnings/should_compile/all.T
index fd2ba85035..10a3ecf12c 100644
--- a/testsuite/tests/warnings/should_compile/all.T
+++ b/testsuite/tests/warnings/should_compile/all.T
@@ -6,9 +6,13 @@ test('T9178', [], multimod_compile, ['T9178', '-Wall'])
 test('T9230', normal, compile, [''])
 
 test('T10908', normal, compile, [''])
+test('T10930', normal, compile, [''])
+test('T10930b', normal, compile, [''])
 test('T11077', normal, compile, ['-fwarn-missing-exported-signatures'])
 test('T11128', normal, compile, [''])
 test('T11128b', normal, compile, [''])
+test('T13256', normal, compile, [''])
+test('T15460', normal, compile, [''])
 test('PluralS', normal, compile, [''])
 
 # T12574 Test that suggest current flag over deprecated
@@ -21,4 +25,6 @@ test('Werror02', normal, compile, [''])
 
 test('MissingMod', normal, multimod_compile, ['MissingMod', '-Wmissing-home-modules'])
 
-test('StarBinder', normal, compile, [''])
\ No newline at end of file
+test('StarBinder', normal, compile, [''])
+
+test('Overflow', normal, compile, [''])