Improve "ambiguous occurrence" error messages

This error was sometimes a bit confusing, especially when data families
were involved. This commit improves the general presentation of the
"ambiguous occurrence" error, and adds a bit of extra context in the
case of data families.

Fixes #23301

6 files changed, 38 insertions, 33 deletions

diff --git a/testsuite/tests/module/mod110.stderr b/testsuite/tests/module/mod110.stderr
index 38e9c79a54..97f7eedadb 100644
--- a/testsuite/tests/module/mod110.stderr
+++ b/testsuite/tests/module/mod110.stderr
@@ -1,7 +1,8 @@
 
 mod110.hs:11:10: error: [GHC-87543]
-    Ambiguous occurrence ‘Eq’
-    It could refer to either ‘Prelude.Eq’,
-                             imported from ‘Prelude’ at mod110.hs:4:1-14
-                             (and originally defined in ‘GHC.Classes’)
-                          or ‘M.Eq’, defined at mod110.hs:7:1
+    Ambiguous occurrence ‘Eq’.
+    It could refer to
+       either ‘Prelude.Eq’,
+              imported from ‘Prelude’ at mod110.hs:4:1-14
+              (and originally defined in ‘GHC.Classes’),
+           or ‘M.Eq’, defined at mod110.hs:7:1.
diff --git a/testsuite/tests/module/mod151.stderr b/testsuite/tests/module/mod151.stderr
index 8bb41459fb..ca382a3155 100644
--- a/testsuite/tests/module/mod151.stderr
+++ b/testsuite/tests/module/mod151.stderr
@@ -1,7 +1,8 @@
 
 mod151.hs:2:20: error: [GHC-87543]
-    Ambiguous occurrence ‘id’
-    It could refer to either ‘Prelude.id’,
-                             imported from ‘Prelude’ at mod151.hs:2:8
-                             (and originally defined in ‘GHC.Base’)
-                          or ‘M.id’, defined at mod151.hs:2:30
+    Ambiguous occurrence ‘id’.
+    It could refer to
+       either ‘Prelude.id’,
+              imported from ‘Prelude’ at mod151.hs:2:8
+              (and originally defined in ‘GHC.Base’),
+           or ‘M.id’, defined at mod151.hs:2:30.
diff --git a/testsuite/tests/module/mod152.stderr b/testsuite/tests/module/mod152.stderr
index d60269b757..9742ed69ba 100644
--- a/testsuite/tests/module/mod152.stderr
+++ b/testsuite/tests/module/mod152.stderr
@@ -1,7 +1,8 @@
 
 mod152.hs:2:26: error: [GHC-87543]
-    Ambiguous occurrence ‘id’
-    It could refer to either ‘Prelude.id’,
-                             imported from ‘Prelude’ at mod152.hs:2:8
-                             (and originally defined in ‘GHC.Base’)
-                          or ‘M.id’, defined at mod152.hs:2:36
+    Ambiguous occurrence ‘id’.
+    It could refer to
+       either ‘Prelude.id’,
+              imported from ‘Prelude’ at mod152.hs:2:8
+              (and originally defined in ‘GHC.Base’),
+           or ‘M.id’, defined at mod152.hs:2:36.
diff --git a/testsuite/tests/module/mod153.stderr b/testsuite/tests/module/mod153.stderr
index 989b27a77e..7d71dbcd0a 100644
--- a/testsuite/tests/module/mod153.stderr
+++ b/testsuite/tests/module/mod153.stderr
@@ -1,7 +1,8 @@
 
 mod153.hs:2:11: error: [GHC-87543]
-    Ambiguous occurrence ‘id’
-    It could refer to either ‘Prelude.id’,
-                             imported from ‘Prelude’ at mod153.hs:2:8
-                             (and originally defined in ‘GHC.Base’)
-                          or ‘M.id’, defined at mod153.hs:2:21
+    Ambiguous occurrence ‘id’.
+    It could refer to
+       either ‘Prelude.id’,
+              imported from ‘Prelude’ at mod153.hs:2:8
+              (and originally defined in ‘GHC.Base’),
+           or ‘M.id’, defined at mod153.hs:2:21.
diff --git a/testsuite/tests/module/mod164.stderr b/testsuite/tests/module/mod164.stderr
index d6c0a9eec2..26de35564e 100644
--- a/testsuite/tests/module/mod164.stderr
+++ b/testsuite/tests/module/mod164.stderr
@@ -1,9 +1,10 @@
 
-mod164.hs:9:5: [GHC-87543]
-    Ambiguous occurrence ‘D1’
-    It could refer to either ‘Mod164_A.D1’,
-                             imported from ‘Mod164_A’ at mod164.hs:4:1-15
-                             (and originally defined at Mod164_A.hs:3:10-11)
-                          or ‘Mod164_B.D1’,
-                             imported from ‘Mod164_B’ at mod164.hs:5:1-15
-                             (and originally defined at Mod164_B.hs:3:10-11)
+mod164.hs:9:5: error: [GHC-87543]
+    Ambiguous occurrence ‘D1’.
+    It could refer to
+       either ‘Mod164_A.D1’,
+              imported from ‘Mod164_A’ at mod164.hs:4:1-15
+              (and originally defined at Mod164_A.hs:3:10-11),
+           or ‘Mod164_B.D1’,
+              imported from ‘Mod164_B’ at mod164.hs:5:1-15
+              (and originally defined at Mod164_B.hs:3:10-11).
diff --git a/testsuite/tests/module/mod165.stderr b/testsuite/tests/module/mod165.stderr
index 9ef57d4bbd..be092c086e 100644
--- a/testsuite/tests/module/mod165.stderr
+++ b/testsuite/tests/module/mod165.stderr
@@ -1,7 +1,7 @@
 
-mod165.hs:9:5: [GHC-87543]
-    Ambiguous occurrence ‘A.D1’
-    It could refer to either ‘A.D1’,
-                             imported from ‘Mod164_A’ at mod165.hs:4:1-20
-                          or ‘A.D1’, imported from ‘Mod164_B’ at mod165.hs:5:1-20
+mod165.hs:9:5: error: [GHC-87543]
+    Ambiguous occurrence ‘A.D1’.
+    It could refer to
+       either ‘A.D1’, imported from ‘Mod164_A’ at mod165.hs:4:1-20,
+           or ‘A.D1’, imported from ‘Mod164_B’ at mod165.hs:5:1-20.
 exit(1)