Add -Wmissing-exported-pattern-synonym-signatures

After !4741, it was no longer possible to silence a warning about a missing
pattern synonym signature if the `-Wmissing-signatures` flag was on.

Restore the previous semantics while still adhering to the principle "enabling
an additional warning flag should never make prior warnings disappear".

For more symmetry and granularity, introduce
`-Wmissing-exported-pattern-synonym-signatures`.

See Note [Missing signatures] for an overview of all flags involved.

15 files changed, 74 insertions, 224 deletions

diff --git a/testsuite/tests/warnings/should_compile/T14794a.hs b/testsuite/tests/warnings/should_compile/T14794a.hs
index 224eaf64f7..216ef832b3 100644
--- a/testsuite/tests/warnings/should_compile/T14794a.hs
+++ b/testsuite/tests/warnings/should_compile/T14794a.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures #-}
+{-# OPTIONS_GHC -Wmissing-signatures #-}
 
-module T14794a (test1, pattern Test2, test3, pattern Test4) where
+module T14794a (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
+-- These should generate warnings:
 
-test3 = True
+testExported = True
 
-pattern Test4 <- True
+testUnexported = True
 
-test7 = True
+-- These should not generate warnings:
 
-pattern Test8 <- True
+pattern TestExported <- True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794a.stderr b/testsuite/tests/warnings/should_compile/T14794a.stderr
index 166d59ab37..807a070350 100644
--- a/testsuite/tests/warnings/should_compile/T14794a.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794a.stderr
@@ -1,12 +1,6 @@
 
-T14794a.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
+T14794a.hs:8:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testExported :: Bool
 
-T14794a.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794a.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794a.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794a.hs:10:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794b.hs b/testsuite/tests/warnings/should_compile/T14794b.hs
index 7c542b4dc1..90501d0fa7 100644
--- a/testsuite/tests/warnings/should_compile/T14794b.hs
+++ b/testsuite/tests/warnings/should_compile/T14794b.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-exported-signatures #-}
+{-# OPTIONS_GHC -Wmissing-exported-signatures #-}
 
-module T14794b (test1, pattern Test2, test3, pattern Test4) where
+module T14794b (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures
+-- These should generate warnings:
 
-test3 = True
+testExported = True
 
-pattern Test4 <- True
+-- These should not generate warnings:
 
-test7 = True
+testUnexported = True
 
-pattern Test8 <- True
+pattern TestExported <- True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures -Wmissing-exported-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794b.stderr b/testsuite/tests/warnings/should_compile/T14794b.stderr
index 6109a4c985..8f7f7e805b 100644
--- a/testsuite/tests/warnings/should_compile/T14794b.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794b.stderr
@@ -1,12 +1,3 @@
 
-T14794b.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
-
-T14794b.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794b.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794b.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794b.hs:8:1: warning: [-Wmissing-exported-signatures]
+    Top-level binding with no type signature: testExported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794c.hs b/testsuite/tests/warnings/should_compile/T14794c.hs
index 742ca3c91c..fd30cfdfcd 100644
--- a/testsuite/tests/warnings/should_compile/T14794c.hs
+++ b/testsuite/tests/warnings/should_compile/T14794c.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-pattern-synonym-signatures #-}
+{-# OPTIONS_GHC -Wmissing-signatures -Wmissing-exported-signatures #-}
 
-module T14794c (test1, pattern Test2, test3, pattern Test4) where
+module T14794c (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures -Wmissing-pattern-synonym-signatures
+-- These should generate warnings:
 
-test3 = True
+testExported = True
 
-pattern Test4 <- True
+testUnexported = True
 
-test7 = True
+-- These should not generate warnings:
 
-pattern Test8 <- True
+pattern TestExported <- True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures -Wmissing-pattern-synonym-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794c.stderr b/testsuite/tests/warnings/should_compile/T14794c.stderr
index 95cbb4d16f..413eea960f 100644
--- a/testsuite/tests/warnings/should_compile/T14794c.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794c.stderr
@@ -1,12 +1,6 @@
 
-T14794c.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
+T14794c.hs:8:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testExported :: Bool
 
-T14794c.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794c.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794c.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794c.hs:10:1: warning: [-Wmissing-signatures (in -Wall)]
+    Top-level binding with no type signature: testUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794d.hs b/testsuite/tests/warnings/should_compile/T14794d.hs
index 8928df75d3..bb9913e6d9 100644
--- a/testsuite/tests/warnings/should_compile/T14794d.hs
+++ b/testsuite/tests/warnings/should_compile/T14794d.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures #-}
+{-# OPTIONS_GHC -Wmissing-pattern-synonym-signatures #-}
 
-module T14794d (test1, pattern Test2, test3, pattern Test4) where
+module T14794d (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
+-- These should generate warnings:
 
-test3 = True
+pattern TestExported <- True
 
-pattern Test4 <- True
+pattern TestUnexported <- True
 
+-- These should not generate warnings:
 
--- This should not generate warnings with;
--- -Wmissing-exported-signatures -Wmissing-pattern-synonym-signatures
+testExported = True
 
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
-
-test7 = True
-
-pattern Test8 <- True
+testUnexported = True
diff --git a/testsuite/tests/warnings/should_compile/T14794d.stderr b/testsuite/tests/warnings/should_compile/T14794d.stderr
index 3388d17316..61177b520e 100644
--- a/testsuite/tests/warnings/should_compile/T14794d.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794d.stderr
@@ -1,6 +1,8 @@
 
-T14794d.hs:9:1: warning: [-Wmissing-exported-signatures]
-    Top-level binding with no type signature: test3 :: Bool
+T14794d.hs:8:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestExported :: Bool
 
-T14794d.hs:11:1: warning: [-Wmissing-exported-signatures]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
+T14794d.hs:10:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794e.hs b/testsuite/tests/warnings/should_compile/T14794e.hs
index 051cf347d6..b53244de6c 100644
--- a/testsuite/tests/warnings/should_compile/T14794e.hs
+++ b/testsuite/tests/warnings/should_compile/T14794e.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-signatures #-}
+{-# OPTIONS_GHC -Wmissing-exported-pattern-synonym-signatures #-}
 
-module T14794e (test1, pattern Test2, test3, pattern Test4) where
+module T14794e (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-signatures
+-- These should generate warnings:
 
-test3 = True
+pattern TestExported <- True
 
-pattern Test4 <- True
+-- These should not generate warnings:
 
-test7 = True
+testExported = True
 
-pattern Test8 <- True
+testUnexported = True
 
-
--- This should not generate warnings with;
--- -Wmissing-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
+pattern TestUnexported <- True
diff --git a/testsuite/tests/warnings/should_compile/T14794e.stderr b/testsuite/tests/warnings/should_compile/T14794e.stderr
index f0e4ddbc4c..b7c70b6e51 100644
--- a/testsuite/tests/warnings/should_compile/T14794e.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794e.stderr
@@ -1,12 +1,4 @@
 
-T14794e.hs:9:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test3 :: Bool
-
-T14794e.hs:11:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794e.hs:13:1: warning: [-Wmissing-signatures (in -Wall)]
-    Top-level binding with no type signature: test7 :: Bool
-
-T14794e.hs:15:1: warning: [-Wmissing-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
+T14794e.hs:8:1: warning: [-Wmissing-exported-pattern-synonym-signatures]
+    Pattern synonym with no type signature:
+      pattern TestExported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794f.hs b/testsuite/tests/warnings/should_compile/T14794f.hs
index c2cf58f174..2ebb7e0235 100644
--- a/testsuite/tests/warnings/should_compile/T14794f.hs
+++ b/testsuite/tests/warnings/should_compile/T14794f.hs
@@ -1,31 +1,16 @@
 {-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-exported-signatures #-}
+{-# OPTIONS_GHC -Wmissing-pattern-synonym-signatures -Wmissing-exported-pattern-synonym-signatures #-}
 
-module T14794f (test1, pattern Test2, test3, pattern Test4) where
+module T14794d (testExported, pattern TestExported) where
 
--- This should generate warnings with;
--- -Wmissing-exported-signatures
+-- These should generate warnings:
 
-test3 = True
+pattern TestExported <- True
 
+pattern TestUnexported <- True
 
--- This should not generate warnings with;
--- -Wmissing-exported-signatures
+-- These should not generate warnings:
 
-test1 :: Bool
-test1 = True
+testExported = True
 
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-pattern Test4 <- True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
-
-test7 = True
-
-pattern Test8 <- True
+testUnexported = True
diff --git a/testsuite/tests/warnings/should_compile/T14794f.stderr b/testsuite/tests/warnings/should_compile/T14794f.stderr
index b751aad98e..fd138d5911 100644
--- a/testsuite/tests/warnings/should_compile/T14794f.stderr
+++ b/testsuite/tests/warnings/should_compile/T14794f.stderr
@@ -1,3 +1,8 @@
 
-T14794f.hs:9:1: warning: [-Wmissing-exported-signatures]
-    Top-level binding with no type signature: test3 :: Bool
+T14794f.hs:8:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestExported :: Bool
+
+T14794f.hs:10:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
+    Pattern synonym with no type signature:
+      pattern TestUnexported :: Bool
diff --git a/testsuite/tests/warnings/should_compile/T14794g.hs b/testsuite/tests/warnings/should_compile/T14794g.hs
deleted file mode 100644
index eec2210203..0000000000
--- a/testsuite/tests/warnings/should_compile/T14794g.hs
+++ /dev/null
@@ -1,31 +0,0 @@
-{-# LANGUAGE PatternSynonyms #-}
-{-# OPTIONS_GHC -Wmissing-pattern-synonym-signatures #-}
-
-module T14794g (test1, pattern Test2, test3, pattern Test4) where
-
--- This should generate warnings with;
--- -Wmissing-pattern-synonym-signatures
-
-pattern Test4 <- True
-
-pattern Test8 <- True
-
-
--- This should not generate warnings with;
--- -Wmissing-pattern-synonym-signatures
-
-test1 :: Bool
-test1 = True
-
-pattern Test2 :: Bool
-pattern Test2 <- True
-
-test3 = True
-
-test5 :: Bool
-test5 = True
-
-pattern Test6 :: Bool
-pattern Test6 <- True
-
-test7 = True
diff --git a/testsuite/tests/warnings/should_compile/T14794g.stderr b/testsuite/tests/warnings/should_compile/T14794g.stderr
deleted file mode 100644
index abd3bf205d..0000000000
--- a/testsuite/tests/warnings/should_compile/T14794g.stderr
+++ /dev/null
@@ -1,6 +0,0 @@
-
-T14794g.hs:9:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test4 :: Bool
-
-T14794g.hs:11:1: warning: [-Wmissing-pattern-synonym-signatures (in -Wall)]
-    Pattern synonym with no type signature: pattern Test8 :: Bool
diff --git a/testsuite/tests/warnings/should_compile/all.T b/testsuite/tests/warnings/should_compile/all.T
index a2b82c9661..849ae5edfa 100644
--- a/testsuite/tests/warnings/should_compile/all.T
+++ b/testsuite/tests/warnings/should_compile/all.T
@@ -4,7 +4,6 @@ test('T14794c', normal, compile, [''])
 test('T14794d', normal, compile, [''])
 test('T14794e', normal, compile, [''])
 test('T14794f', normal, compile, [''])
-test('T14794g', normal, compile, [''])
 
 test('T9178', [], multimod_compile, ['T9178', '-Wall'])