Snapshots Pat = Var = Expr

Summary: Snapshot tests for exprs of the form `Pat = Var = Expr`.

Reviewed By: michalmuskala

Differential Revision: D84819136

fbshipit-source-id: a229e453ea48d2bb6b0b45ad430d362b765f58ee

Author: VLanvin

crates/elp/src/resources/test/eqwalizer_tests/check/pats-OTP-26.pretty

@@ -0,0 +1,45 @@
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/pats.erl:21:17
+   │
+21 │     maps:get(a, M).
+   │                 ^
+   │                 │
+   │                 M.
+Expression has type:   #{a => 'ok'} | 'error'
+Context expected type: #{term() => term()}
+   │                 
+
+Because in the expression's type:
+  Here the type is a union type with some valid candidates: #{a => 'ok'}
+  However the following candidate: 'error'
+  Differs from the expected type:  #{term() => term()}
+
+------------------------------ Detailed message ------------------------------
+
+  #{a => 'ok'} | 'error' is not compatible with #{term() => term()}
+  because
+  'error' is not compatible with #{term() => term()}
+
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/pats.erl:26:17
+   │
+26 │     maps:get(a, M).
+   │                 ^
+   │                 │
+   │                 M.
+Expression has type:   #{a => 'ok'} | 'error'
+Context expected type: #{term() => term()}
+   │                 
+
+Because in the expression's type:
+  Here the type is a union type with some valid candidates: #{a => 'ok'}
+  However the following candidate: 'error'
+  Differs from the expected type:  #{term() => term()}
+
+------------------------------ Detailed message ------------------------------
+
+  #{a => 'ok'} | 'error' is not compatible with #{term() => term()}
+  because
+  'error' is not compatible with #{term() => term()}
+
+2 ERRORS

crates/elp/src/resources/test/eqwalizer_tests/check/pats-OTP-27.pretty

@@ -0,0 +1,45 @@
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/pats.erl:21:17
+   │
+21 │     maps:get(a, M).
+   │                 ^
+   │                 │
+   │                 M.
+Expression has type:   #{a => 'ok'} | 'error'
+Context expected type: #{term() => term()}
+   │                 
+
+Because in the expression's type:
+  Here the type is a union type with some valid candidates: #{a => 'ok'}
+  However the following candidate: 'error'
+  Differs from the expected type:  #{term() => term()}
+
+------------------------------ Detailed message ------------------------------
+
+  #{a => 'ok'} | 'error' is not compatible with #{term() => term()}
+  because
+  'error' is not compatible with #{term() => term()}
+
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/pats.erl:26:17
+   │
+26 │     maps:get(a, M).
+   │                 ^
+   │                 │
+   │                 M.
+Expression has type:   #{a => 'ok'} | 'error'
+Context expected type: #{term() => term()}
+   │                 
+
+Because in the expression's type:
+  Here the type is a union type with some valid candidates: #{a => 'ok'}
+  However the following candidate: 'error'
+  Differs from the expected type:  #{term() => term()}
+
+------------------------------ Detailed message ------------------------------
+
+  #{a => 'ok'} | 'error' is not compatible with #{term() => term()}
+  because
+  'error' is not compatible with #{term() => term()}
+
+2 ERRORS

crates/elp/src/resources/test/eqwalizer_tests/check/pats-OTP-28.pretty

@@ -0,0 +1,45 @@
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/pats.erl:21:17
+   │
+21 │     maps:get(a, M).
+   │                 ^
+   │                 │
+   │                 M.
+Expression has type:   #{a => 'ok'} | 'error'
+Context expected type: #{term() => term()}
+   │                 
+
+Because in the expression's type:
+  Here the type is a union type with some valid candidates: #{a => 'ok'}
+  However the following candidate: 'error'
+  Differs from the expected type:  #{term() => term()}
+
+------------------------------ Detailed message ------------------------------
+
+  #{a => 'ok'} | 'error' is not compatible with #{term() => term()}
+  because
+  'error' is not compatible with #{term() => term()}
+
+error: incompatible_types (See https://fb.me/eqwalizer_errors#incompatible_types)
+   ┌─ check/src/pats.erl:26:17
+   │
+26 │     maps:get(a, M).
+   │                 ^
+   │                 │
+   │                 M.
+Expression has type:   #{a => 'ok'} | 'error'
+Context expected type: #{term() => term()}
+   │                 
+
+Because in the expression's type:
+  Here the type is a union type with some valid candidates: #{a => 'ok'}
+  However the following candidate: 'error'
+  Differs from the expected type:  #{term() => term()}
+
+------------------------------ Detailed message ------------------------------
+
+  #{a => 'ok'} | 'error' is not compatible with #{term() => term()}
+  because
+  'error' is not compatible with #{term() => term()}
+
+2 ERRORS

test_projects/eqwalizer_tests/check/src/pats.erl

@@ -0,0 +1,31 @@
+%%% Copyright (c) Meta Platforms, Inc. and affiliates. All rights reserved.
+%%%
+%%% This source code is licensed under the Apache 2.0 license found in
+%%% the LICENSE file in the root directory of this source tree.
+
+-module(pats).
+
+-compile([export_all, nowarn_export_all]).
+
+-spec return_map() -> #{a => ok} | error.
+return_map() -> #{a => ok}.
+
+-spec patmatch1() -> ok.
+patmatch1() ->
+    #{a := V} = _M = return_map(),
+    V.
+
+-spec patmatch2() -> ok.
+patmatch2() ->
+    #{a := _V} = M = return_map(),
+    maps:get(a, M).
+
+-spec patmatch3_neg() -> ok.
+patmatch3_neg() ->
+    _V = M = return_map(),
+    maps:get(a, M).
+
+-spec patmatch4() -> ok.
+patmatch4() ->
+    M = #{a := _V} = return_map(),
+    maps:get(a, M).