Useless error messages -- repro

Summary: Some error messages with unions of maps are useless. Add repros.

Reviewed By: TD5

Differential Revision: D85868726

fbshipit-source-id: c726054b934690f30bc3e5c190d55e9dd25e361f

Author: VLanvin

crates/elp/src/resources/test/eqwalizer_tests/check/error_messages.pretty

@@ -125,4 +125,64 @@ Because in the expression's type:
   because
   atom() is not compatible with binary()
 
-6 ERRORS
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/error_messages.erl:37:31
+   │
+37 │ no_good_map_candidate_1(M) -> M.
+   │                               ^
+   │                               │
+   │                               M.
+Expression has type:   #{foo => #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'}}
+Context expected type: #{foo => #{large_map_key_c => 'large_map_val_c'} | #{large_map_key_d => 'large_map_val_d'}}
+   │                               
+
+Because in the expression's type:
+  #{ foo =>
+    Here the type is:     #{...}
+    Context expects type: #{...} | #{...}
+    No candidate matches in the expected union.
+  , ... }
+
+------------------------------ Detailed message ------------------------------
+
+  #{foo => #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'}} is not compatible with #{foo => #{large_map_key_c => 'large_map_val_c'} | #{large_map_key_d => 'large_map_val_d'}}
+  because
+  at key `foo`:
+  #{foo => #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'}} is not compatible with #{foo => #{large_map_key_c => 'large_map_val_c'} | #{large_map_key_d => 'large_map_val_d'}}
+  because
+  #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'} is not compatible with #{large_map_key_c => 'large_map_val_c'} | #{large_map_key_d => 'large_map_val_d'}
+  because
+  #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'} is not compatible with #{large_map_key_c => 'large_map_val_c'}
+  key `large_map_key_a` is declared in the former but not in the latter and the latter map has no default association
+
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/error_messages.erl:41:31
+   │
+41 │ no_good_map_candidate_2(M) -> M.
+   │                               ^
+   │                               │
+   │                               M.
+Expression has type:   #{foo => #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'}}
+Context expected type: #{foo => #{large_map_key_c => 'large_map_val_c', large_map_key_d => 'large_map_val_d'} | 'any'}
+   │                               
+
+Because in the expression's type:
+  #{ foo =>
+    Here the type is:     #{...}
+    Context expects type: #{...} | 'any'
+    No candidate matches in the expected union.
+  , ... }
+
+------------------------------ Detailed message ------------------------------
+
+  #{foo => #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'}} is not compatible with #{foo => #{large_map_key_c => 'large_map_val_c', large_map_key_d => 'large_map_val_d'} | 'any'}
+  because
+  at key `foo`:
+  #{foo => #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'}} is not compatible with #{foo => #{large_map_key_c => 'large_map_val_c', large_map_key_d => 'large_map_val_d'} | 'any'}
+  because
+  #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'} is not compatible with #{large_map_key_c => 'large_map_val_c', large_map_key_d => 'large_map_val_d'} | 'any'
+  because
+  #{large_map_key_a => 'large_map_val_a', large_map_key_b => 'large_map_val_b'} is not compatible with #{large_map_key_c => 'large_map_val_c', large_map_key_d => 'large_map_val_d'}
+  key `large_map_key_a` is declared in the former but not in the latter and the latter map has no default association
+
+8 ERRORS

test_projects/eqwalizer_tests/check/src/error_messages.erl

@@ -31,3 +31,11 @@ no_record_conversion_2(Foo) -> Foo.
 
 -spec record_conversion(#foo{}) -> {foo, binary(), atom()}.
 record_conversion(Foo) -> Foo.
+
+-spec no_good_map_candidate_1(#{foo => #{large_map_key_a => large_map_val_a, large_map_key_b => large_map_val_b}})
+    -> #{foo => #{large_map_key_c => large_map_val_c} | #{large_map_key_d => large_map_val_d}}.
+no_good_map_candidate_1(M) -> M.
+
+-spec no_good_map_candidate_2(#{foo => #{large_map_key_a => large_map_val_a, large_map_key_b => large_map_val_b}})
+    -> #{foo => #{large_map_key_c => large_map_val_c, large_map_key_d => large_map_val_d} | any}.
+no_good_map_candidate_2(M) -> M.