Only suggest names that make sense (#19843)

* Don't show suggestions for similar variables when a data constructor
  in a pattern is not in scope.

* Only suggest record fields when a record field for record creation or
  updating is not in scope.

* Suggest similar record fields when a record field is not in scope with
  -XOverloadedRecordDot.

* Show suggestions for data constructors if a type constructor or type
  is not in scope, but only if -XDataKinds is enabled.

Fixes #19843.

29 files changed, 213 insertions, 3 deletions

diff --git a/testsuite/tests/rename/should_fail/T19843a.hs b/testsuite/tests/rename/should_fail/T19843a.hs
new file mode 100644
index 0000000000..746357d3e8
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843a.hs
@@ -0,0 +1,5 @@
+module T19843a where
+
+import Prelude (map, undefined)
+
+foo (Map k v) = undefined
diff --git a/testsuite/tests/rename/should_fail/T19843a.stderr b/testsuite/tests/rename/should_fail/T19843a.stderr
new file mode 100644
index 0000000000..8f96612743
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843a.stderr
@@ -0,0 +1,3 @@
+
+T19843a.hs:5:6:
+    Not in scope: data constructor ‘Map’
diff --git a/testsuite/tests/rename/should_fail/T19843b.hs b/testsuite/tests/rename/should_fail/T19843b.hs
new file mode 100644
index 0000000000..4bd6ef2d1b
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843b.hs
@@ -0,0 +1,7 @@
+{-# LANGUAGE ViewPatterns #-}
+
+module T19843b where
+
+import Prelude (map, even, undefined, Bool)
+
+foo (Map even -> xs) = undefined
diff --git a/testsuite/tests/rename/should_fail/T19843b.stderr b/testsuite/tests/rename/should_fail/T19843b.stderr
new file mode 100644
index 0000000000..5b457440eb
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843b.stderr
@@ -0,0 +1,4 @@
+
+T19843b.hs:7:6:
+    • Data constructor not in scope: Map :: (a0 -> Bool) -> t -> t0
+    • Perhaps you meant variable ‘map’ (imported from Prelude)
diff --git a/testsuite/tests/rename/should_fail/T19843c.hs b/testsuite/tests/rename/should_fail/T19843c.hs
new file mode 100644
index 0000000000..1b55bce68b
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843c.hs
@@ -0,0 +1,6 @@
+module T19843c where
+
+import Data.Map as Map
+import Prelude (undefined, map)
+
+foo (Map.Map k v) = undefined
diff --git a/testsuite/tests/rename/should_fail/T19843c.stderr b/testsuite/tests/rename/should_fail/T19843c.stderr
new file mode 100644
index 0000000000..94cdadf528
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843c.stderr
@@ -0,0 +1,4 @@
+
+T19843c.hs:6:6: error:
+    Not in scope: data constructor ‘Map.Map’
+    Module ‘Data.Map’ does not export ‘Map’.
diff --git a/testsuite/tests/rename/should_fail/T19843d.hs b/testsuite/tests/rename/should_fail/T19843d.hs
new file mode 100644
index 0000000000..72ddc65f3a
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843d.hs
@@ -0,0 +1,7 @@
+module T19843d where
+
+import Prelude (undefined, map)
+
+data Mup k v = Mup k v
+
+foo (Map k v) = undefined
diff --git a/testsuite/tests/rename/should_fail/T19843d.stderr b/testsuite/tests/rename/should_fail/T19843d.stderr
new file mode 100644
index 0000000000..a27a627005
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843d.stderr
@@ -0,0 +1,4 @@
+
+T19843d.hs:7:6: error:
+    Not in scope: data constructor ‘Map’
+    Perhaps you meant ‘Mup’ (line 5)
diff --git a/testsuite/tests/rename/should_fail/T19843e.hs b/testsuite/tests/rename/should_fail/T19843e.hs
new file mode 100644
index 0000000000..9223f6e169
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843e.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE PatternSynonyms #-}
+
+module T19843e where
+
+import Prelude (undefined, map, Maybe(Just))
+
+pattern Mup k = Just k
+
+foo (Map k) = undefined
diff --git a/testsuite/tests/rename/should_fail/T19843e.stderr b/testsuite/tests/rename/should_fail/T19843e.stderr
new file mode 100644
index 0000000000..890c719bd8
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843e.stderr
@@ -0,0 +1,4 @@
+
+T19843e.hs:9:6: error:
+    Not in scope: data constructor ‘Map’
+    Perhaps you meant ‘Mup’ (line 7)
diff --git a/testsuite/tests/rename/should_fail/T19843f.hs b/testsuite/tests/rename/should_fail/T19843f.hs
new file mode 100644
index 0000000000..64beb233fa
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843f.hs
@@ -0,0 +1,10 @@
+module T19843f where
+
+import Prelude (Int, map)
+
+data A = A {mop :: ()}
+data Mup = Mup
+
+foo = foo {mup = 1}
+
+bar = A {mup = 1}
diff --git a/testsuite/tests/rename/should_fail/T19843f.stderr b/testsuite/tests/rename/should_fail/T19843f.stderr
new file mode 100644
index 0000000000..903fee7849
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843f.stderr
@@ -0,0 +1,8 @@
+
+T19843f.hs:8:12: error:
+    Not in scope: ‘mup’
+    Perhaps you meant ‘mop’ (line 5)
+
+T19843f.hs:10:10: error:
+    Not in scope: ‘mup’
+    Perhaps you meant ‘mop’ (line 5)
diff --git a/testsuite/tests/rename/should_fail/T19843g.hs b/testsuite/tests/rename/should_fail/T19843g.hs
new file mode 100644
index 0000000000..22db3381f3
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843g.hs
@@ -0,0 +1,10 @@
+{-# LANGUAGE NoFieldSelectors #-}
+
+module T19843g where
+
+import Prelude (Int, map)
+
+data A = A {mop :: ()}
+data Mup = Mup
+
+foo = foo {mup = 1}
diff --git a/testsuite/tests/rename/should_fail/T19843g.stderr b/testsuite/tests/rename/should_fail/T19843g.stderr
new file mode 100644
index 0000000000..6d0d398bfd
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843g.stderr
@@ -0,0 +1,4 @@
+
+T19843g.hs:10:12: error:
+    Not in scope: ‘mup’
+    Perhaps you meant ‘mop’ (line 7)
diff --git a/testsuite/tests/rename/should_fail/T19843h.hs b/testsuite/tests/rename/should_fail/T19843h.hs
new file mode 100644
index 0000000000..d78418555f
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843h.hs
@@ -0,0 +1,24 @@
+{-# LANGUAGE NoFieldSelectors #-}
+{-# LANGUAGE OverloadedRecordDot #-}
+
+module T19843h where
+
+import Prelude (Int, map, undefined)
+import Data.Traversable hiding (traverse)
+import qualified Data.Monoid (Sum(..), getSum)
+import Data.Monoid (Alt(..))
+
+data A = A {mop :: ()}
+data Mup = Mup
+
+foo = undefined.mup
+
+bar = undefined.traverse
+
+baz = undefined.getSum
+
+quux = undefined.getAlt
+
+quuz = getAlt undefined
+
+quur = undefined.getAll
diff --git a/testsuite/tests/rename/should_fail/T19843h.stderr b/testsuite/tests/rename/should_fail/T19843h.stderr
new file mode 100644
index 0000000000..56bca0feeb
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843h.stderr
@@ -0,0 +1,34 @@
+
+T19843h.hs:14:7:
+     No instance for (GHC.Records.HasField "mup" r4 a4)
+        arising from selecting the field ‘mup’
+      Perhaps you meant ‘mop’ (line 11)
+     In the expression: undefined.mup
+      In an equation for ‘foo’: foo = undefined.mup
+
+T19843h.hs:16:7:
+     No instance for (GHC.Records.HasField "traverse" r3 a3)
+        arising from selecting the field ‘traverse’
+     In the expression: undefined.traverse
+      In an equation for ‘bar’: bar = undefined.traverse
+
+T19843h.hs:18:7:
+     No instance for (GHC.Records.HasField "getSum" r2 a2)
+        arising from selecting the field ‘getSum’
+     In the expression: undefined.getSum
+      In an equation for ‘baz’: baz = undefined.getSum
+
+T19843h.hs:20:8:
+     No instance for (GHC.Records.HasField "getAlt" r1 a1)
+        arising from selecting the field ‘getAlt’
+     In the expression: undefined.getAlt
+      In an equation for ‘quux’: quux = undefined.getAlt
+
+T19843h.hs:24:8:
+     No instance for (GHC.Records.HasField "getAll" r0 a0)
+        arising from selecting the field ‘getAll’
+      Perhaps you meant ‘getAlt’ (imported from Data.Monoid)
+      Perhaps you want to add ‘getAll’ to the import list
+      in the import of ‘Data.Monoid’ (T19843h.hs:9:1-28).
+     In the expression: undefined.getAll
+      In an equation for ‘quur’: quur = undefined.getAll
diff --git a/testsuite/tests/rename/should_fail/T19843i.hs b/testsuite/tests/rename/should_fail/T19843i.hs
new file mode 100644
index 0000000000..5ed9668577
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843i.hs
@@ -0,0 +1,5 @@
+module T19843i where
+
+import Data.Monoid as M (getAll)
+
+x = M.getSum
diff --git a/testsuite/tests/rename/should_fail/T19843i.stderr b/testsuite/tests/rename/should_fail/T19843i.stderr
new file mode 100644
index 0000000000..60f671c679
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843i.stderr
@@ -0,0 +1,5 @@
+
+T19843i.hs:5:5:
+    Not in scope: ‘M.getSum’
+    Perhaps you want to add ‘getSum’ to the import list
+    in the import of ‘Data.Monoid’ (T19843i.hs:3:1-32).
diff --git a/testsuite/tests/rename/should_fail/T19843j.hs b/testsuite/tests/rename/should_fail/T19843j.hs
new file mode 100644
index 0000000000..20cd1c84d8
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843j.hs
@@ -0,0 +1,5 @@
+module T19843j where
+
+import Control.Monad (sequence)
+
+x = guard
diff --git a/testsuite/tests/rename/should_fail/T19843j.stderr b/testsuite/tests/rename/should_fail/T19843j.stderr
new file mode 100644
index 0000000000..e99a9f0a62
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843j.stderr
@@ -0,0 +1,5 @@
+
+T19843j.hs:5:5:
+     Variable not in scope: guard
+     Perhaps you want to add ‘guard’ to the import list
+      in the import of ‘Control.Monad’ (T19843j.hs:3:1-31).
diff --git a/testsuite/tests/rename/should_fail/T19843k.hs b/testsuite/tests/rename/should_fail/T19843k.hs
new file mode 100644
index 0000000000..d97819b306
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843k.hs
@@ -0,0 +1,5 @@
+module T19843k where
+
+import Data.Monoid as M
+
+main = M.doesn'tExist
diff --git a/testsuite/tests/rename/should_fail/T19843k.stderr b/testsuite/tests/rename/should_fail/T19843k.stderr
new file mode 100644
index 0000000000..08ed7d8c08
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843k.stderr
@@ -0,0 +1,4 @@
+
+T19843k.hs:5:8:
+    Not in scope: ‘M.doesn'tExist’
+    Module ‘Data.Monoid’ does not export ‘doesn'tExist’.
diff --git a/testsuite/tests/rename/should_fail/T19843l.hs b/testsuite/tests/rename/should_fail/T19843l.hs
new file mode 100644
index 0000000000..340fe68539
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843l.hs
@@ -0,0 +1,7 @@
+module T19843l where
+
+data Foo = LongName
+data FongName
+wrongName = wrongName
+
+type Bar = WrongName
diff --git a/testsuite/tests/rename/should_fail/T19843l.stderr b/testsuite/tests/rename/should_fail/T19843l.stderr
new file mode 100644
index 0000000000..d5168b2b90
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843l.stderr
@@ -0,0 +1,4 @@
+
+T19843l.hs:7:12:
+    Not in scope: type constructor or class ‘WrongName’
+    Perhaps you meant ‘FongName’ (line 4)
diff --git a/testsuite/tests/rename/should_fail/T19843m.hs b/testsuite/tests/rename/should_fail/T19843m.hs
new file mode 100644
index 0000000000..72c08b2fdd
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843m.hs
@@ -0,0 +1,9 @@
+{-# LANGUAGE DataKinds #-}
+
+module T19843m where
+
+data Foo = LongName
+data FongName
+wrongName = wrongName
+
+type Bar = WrongName
diff --git a/testsuite/tests/rename/should_fail/T19843m.stderr b/testsuite/tests/rename/should_fail/T19843m.stderr
new file mode 100644
index 0000000000..dd7583842a
--- /dev/null
+++ b/testsuite/tests/rename/should_fail/T19843m.stderr
@@ -0,0 +1,5 @@
+
+T19843m.hs:9:12:
+    Not in scope: type constructor or class ‘WrongName’
+    Perhaps you meant one of these:
+      ‘FongName’ (line 6), data constructor ‘LongName’ (line 5)
diff --git a/testsuite/tests/rename/should_fail/T9177.hs b/testsuite/tests/rename/should_fail/T9177.hs
index 553dbc7b53..2554e90a65 100644
--- a/testsuite/tests/rename/should_fail/T9177.hs
+++ b/testsuite/tests/rename/should_fail/T9177.hs
@@ -12,7 +12,8 @@ type Foo2 = (integerr)
 foo3 = bar
 foo4 = Fun
 
--- this warning is suboptimal (fun would be illegal here)
+-- this warning was suboptimal (fun would be illegal here) as of #9177
+-- fixed with #19843
 foo5 Fun = ()
 
 -- No errors here:
diff --git a/testsuite/tests/rename/should_fail/T9177.stderr b/testsuite/tests/rename/should_fail/T9177.stderr
index b336b32524..a1153b4fcb 100644
--- a/testsuite/tests/rename/should_fail/T9177.stderr
+++ b/testsuite/tests/rename/should_fail/T9177.stderr
@@ -7,6 +7,5 @@ T9177.hs:7:14: error:
     Not in scope: type variable ‘integerr’
     Perhaps you meant type constructor or class ‘Integer’ (imported from Prelude)
 
-T9177.hs:16:6: error:
+T9177.hs:17:6: error:
     Not in scope: data constructor ‘Fun’
-    Perhaps you meant variable ‘fun’ (line 20)
diff --git a/testsuite/tests/rename/should_fail/all.T b/testsuite/tests/rename/should_fail/all.T
index a5dd61e575..d709fd0ad0 100644
--- a/testsuite/tests/rename/should_fail/all.T
+++ b/testsuite/tests/rename/should_fail/all.T
@@ -165,3 +165,16 @@ test('T18240b', normal, compile_fail, [''])
 test('T18740a', normal, compile_fail, [''])
 test('T18740b', normal, compile_fail, [''])
 test('T19781', [extra_files(['T19781_A.hs', 'T19781_A.hs-boot'])], multimod_compile_fail, ['T19781', '-v0'])
+test('T19843a', normal, compile_fail, [''])
+test('T19843b', normal, compile_fail, [''])
+test('T19843c', normal, compile_fail, [''])
+test('T19843d', normal, compile_fail, [''])
+test('T19843e', normal, compile_fail, [''])
+test('T19843f', normal, compile_fail, [''])
+test('T19843g', normal, compile_fail, [''])
+test('T19843h', normal, compile_fail, [''])
+test('T19843i', normal, compile_fail, [''])
+test('T19843j', normal, compile_fail, [''])
+test('T19843k', normal, compile_fail, [''])
+test('T19843l', normal, compile_fail, [''])
+test('T19843m', normal, compile_fail, [''])