Fix #13948 by being pickier about when to suggest DataKinds

Commit 343cb32d0983f576d344a2d04a35c3fd6eecf2c5 (#13568) made GHC a bit
too cavalier in suggesting when data constructors are in scope (and
suggesting the use of `DataKinds`). This tones down the suggestions so
that `DataKinds` is only suggested if a data constructor of that name is
actually in scope (previously, it would always suggest, even if it was
out of scope).

Fixes #13948.

Test Plan: ./validate

Reviewers: mpickering, austin, bgamari

Reviewed By: mpickering

Subscribers: rwbarton, thomie

GHC Trac Issues: #13948

Differential Revision: https://phabricator.haskell.org/D3719

13 files changed, 5 insertions, 24 deletions

diff --git a/testsuite/tests/module/mod122.stderr b/testsuite/tests/module/mod122.stderr
index 66aaaf2304..51338f0a06 100644
--- a/testsuite/tests/module/mod122.stderr
+++ b/testsuite/tests/module/mod122.stderr
@@ -1,4 +1,2 @@
 
-mod122.hs:5:6: error:
-    Not in scope: type constructor or class ‘C’
-    A data constructor of that name is in scope; did you mean DataKinds?
+mod122.hs:5:6: error: Not in scope: type constructor or class ‘C’
diff --git a/testsuite/tests/module/mod123.stderr b/testsuite/tests/module/mod123.stderr
index 38390d05d1..c31f6d5a39 100644
--- a/testsuite/tests/module/mod123.stderr
+++ b/testsuite/tests/module/mod123.stderr
@@ -1,4 +1,2 @@
 
-mod123.hs:5:6: error:
-    Not in scope: type constructor or class ‘T’
-    A data constructor of that name is in scope; did you mean DataKinds?
+mod123.hs:5:6: error: Not in scope: type constructor or class ‘T’
diff --git a/testsuite/tests/module/mod124.stderr b/testsuite/tests/module/mod124.stderr
index cbf9f4558e..a052a506ad 100644
--- a/testsuite/tests/module/mod124.stderr
+++ b/testsuite/tests/module/mod124.stderr
@@ -1,6 +1,5 @@
 
 mod124.hs:6:6: error:
     Not in scope: type constructor or class ‘T’
-    A data constructor of that name is in scope; did you mean DataKinds?
     Perhaps you want to remove ‘T’ from the explicit hiding list
     in the import of ‘Mod124_A’ (mod124.hs:4:1-26).
diff --git a/testsuite/tests/module/mod127.stderr b/testsuite/tests/module/mod127.stderr
index 462ebbccaf..861d492d1a 100644
--- a/testsuite/tests/module/mod127.stderr
+++ b/testsuite/tests/module/mod127.stderr
@@ -1,6 +1,5 @@
 
 mod127.hs:6:6: error:
     Not in scope: type constructor or class ‘T’
-    A data constructor of that name is in scope; did you mean DataKinds?
     Perhaps you want to remove ‘T’ from the explicit hiding list
     in the import of ‘Mod127_A’ (mod127.hs:4:1-26).
diff --git a/testsuite/tests/module/mod29.stderr b/testsuite/tests/module/mod29.stderr
index 08a019e13d..e70c5df83d 100644
--- a/testsuite/tests/module/mod29.stderr
+++ b/testsuite/tests/module/mod29.stderr
@@ -1,6 +1,5 @@
 
 mod29.hs:6:12: error:
     Not in scope: type constructor or class ‘Char’
-    A data constructor of that name is in scope; did you mean DataKinds?
     Perhaps you want to add ‘Char’ to the import list in the import of
     ‘Prelude’ (mod29.hs:5:1-19).
diff --git a/testsuite/tests/module/mod50.stderr b/testsuite/tests/module/mod50.stderr
index 94878a8faa..9669427f8f 100644
--- a/testsuite/tests/module/mod50.stderr
+++ b/testsuite/tests/module/mod50.stderr
@@ -1,4 +1,2 @@
 
-mod50.hs:3:22: error:
-    Not in scope: type constructor or class ‘Foo’
-    A data constructor of that name is in scope; did you mean DataKinds?
+mod50.hs:3:22: error: Not in scope: type constructor or class ‘Foo’
diff --git a/testsuite/tests/parser/should_fail/readFail001.stderr b/testsuite/tests/parser/should_fail/readFail001.stderr
index 3284c1b51c..6425d16c49 100644
--- a/testsuite/tests/parser/should_fail/readFail001.stderr
+++ b/testsuite/tests/parser/should_fail/readFail001.stderr
@@ -16,4 +16,3 @@ readFail001.hs:107:42: error: Not in scope: data constructor ‘Bar’
 
 readFail001.hs:112:23: error:
     Not in scope: type constructor or class ‘Foo’
-    A data constructor of that name is in scope; did you mean DataKinds?
diff --git a/testsuite/tests/rename/prog003/rename.prog003.stderr b/testsuite/tests/rename/prog003/rename.prog003.stderr
index 6babd0383b..b8f84781a6 100644
--- a/testsuite/tests/rename/prog003/rename.prog003.stderr
+++ b/testsuite/tests/rename/prog003/rename.prog003.stderr
@@ -1,4 +1,2 @@
 
-B.hs:4:6: error:
-    Not in scope: type constructor or class ‘Class’
-    A data constructor of that name is in scope; did you mean DataKinds?
+B.hs:4:6: error: Not in scope: type constructor or class ‘Class’
diff --git a/testsuite/tests/rename/should_fail/T1595a.stderr b/testsuite/tests/rename/should_fail/T1595a.stderr
index 9b19421f3a..bcd601a377 100644
--- a/testsuite/tests/rename/should_fail/T1595a.stderr
+++ b/testsuite/tests/rename/should_fail/T1595a.stderr
@@ -1,4 +1,3 @@
 
 T1595a.hs:3:20: error:
     Not in scope: type constructor or class ‘Tpyo’
-    A data constructor of that name is in scope; did you mean DataKinds?
diff --git a/testsuite/tests/rename/should_fail/T5745.stderr b/testsuite/tests/rename/should_fail/T5745.stderr
index 94e3bd5217..dc590bba33 100644
--- a/testsuite/tests/rename/should_fail/T5745.stderr
+++ b/testsuite/tests/rename/should_fail/T5745.stderr
@@ -1,4 +1,2 @@
 
-T5745.hs:5:6: error:
-    Not in scope: type constructor or class ‘T’
-    A data constructor of that name is in scope; did you mean DataKinds?
+T5745.hs:5:6: error: Not in scope: type constructor or class ‘T’
diff --git a/testsuite/tests/typecheck/should_fail/T1595.stderr b/testsuite/tests/typecheck/should_fail/T1595.stderr
index bed30c42cf..2f17fb8ffb 100644
--- a/testsuite/tests/typecheck/should_fail/T1595.stderr
+++ b/testsuite/tests/typecheck/should_fail/T1595.stderr
@@ -1,8 +1,6 @@
 
 T1595.hs:8:15: error:
     Not in scope: type constructor or class ‘DoesNotExist’
-    A data constructor of that name is in scope; did you mean DataKinds?
 
 T1595.hs:13:22: error:
     Not in scope: type constructor or class ‘DoesNotExist’
-    A data constructor of that name is in scope; did you mean DataKinds?
diff --git a/testsuite/tests/typecheck/should_fail/tcfail048.stderr b/testsuite/tests/typecheck/should_fail/tcfail048.stderr
index 4c1c300ef8..49c8cf0360 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail048.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail048.stderr
@@ -1,4 +1,3 @@
 
 tcfail048.hs:3:8: error:
     Not in scope: type constructor or class ‘B’
-    A data constructor of that name is in scope; did you mean DataKinds?
diff --git a/testsuite/tests/typecheck/should_fail/tcfail053.stderr b/testsuite/tests/typecheck/should_fail/tcfail053.stderr
index edd1537b14..75308e5fca 100644
--- a/testsuite/tests/typecheck/should_fail/tcfail053.stderr
+++ b/testsuite/tests/typecheck/should_fail/tcfail053.stderr
@@ -1,4 +1,3 @@
 
 tcfail053.hs:3:12: error:
     Not in scope: type constructor or class ‘A’
-    A data constructor of that name is in scope; did you mean DataKinds?