Prohibit pipe & arrow function combination that leads to confusing parse trees

See https://externals.io/message/128473
Closes GH-19533

Author: iluuu1994

NEWS

@@ -27,6 +27,8 @@ PHP                                                                        NEWS
   . Various closure binding issues are now deprecated. (alexandre-daubois)
   . Fixed bug GH-18373 (Don't substitute self/parent with anonymous class).
     (ilutov)
+  . Prohibit pipe & arrow function combination that leads to confusing parse
+    trees. (ilutov)
 
 - Filter:
   . Added support for configuring the URI parser for FILTER_VALIDATE_URL

Zend/tests/arrow_functions/gh7900.phpt

@@ -23,4 +23,4 @@ try {
 ?>
 --EXPECT--
 Here
-assert(fn(): never => 42 && false)
+assert((fn(): never => 42) && false)

Zend/tests/pipe_operator/mixed_callable_call.phpt

@@ -71,7 +71,7 @@ $res1 = 1
     |> [StaticTest::class, 'times17']
     |> new Times23()
     |> $times29
-    |> fn($x) => times2($x)
+    |> (fn($x) => times2($x))
 ;
 
 var_dump($res1);

Zend/tests/pipe_operator/prec_001.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Pipe precedence 001
+--FILE--
+<?php
+
+42
+    |> fn($x) => $x < 42
+    |> fn($x) => var_dump($x);
+
+?>
+--EXPECTF--
+Fatal error: Arrow functions on the right hand side of |> must be parenthesized in %s on line %d

Zend/tests/pipe_operator/prec_002.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Pipe precedence 002
+--FILE--
+<?php
+
+42
+    |> (fn($x) => $x < 42)
+    |> (fn($x) => var_dump($x));
+
+?>
+--EXPECT--
+bool(false)

Zend/tests/pipe_operator/prec_003.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Pipe precedence 003
+--FILE--
+<?php
+
+null
+    |> fn() => print (new Exception)->getTraceAsString() . "\n\n"
+    |> fn() => print (new Exception)->getTraceAsString() . "\n\n";
+
+?>
+--EXPECTF--
+Fatal error: Arrow functions on the right hand side of |> must be parenthesized in %s on line %d

Zend/tests/pipe_operator/prec_004.phpt

@@ -0,0 +1,16 @@
+--TEST--
+Pipe precedence 004
+--FILE--
+<?php
+
+null
+    |> (fn() => print (new Exception)->getTraceAsString() . "\n\n")
+    |> (fn() => print (new Exception)->getTraceAsString() . "\n\n");
+
+?>
+--EXPECTF--
+#0 %s(%d): {closure:%s:%d}(NULL)
+#1 {main}
+
+#0 %s(%d): {closure:%s:%d}(1)
+#1 {main}

Zend/tests/pipe_operator/prec_005.phpt

@@ -0,0 +1,14 @@
+--TEST--
+Pipe precedence 005
+--FILE--
+<?php
+
+try {
+    assert(false && 1 |> (fn() => 2));
+} catch (AssertionError $e) {
+    echo $e->getMessage(), "\n";
+}
+
+?>
+--EXPECT--
+assert(false && 1 |> (fn() => 2))

Zend/tests/pipe_operator/prec_006.phpt

@@ -0,0 +1,13 @@
+--TEST--
+Pipe precedence 006
+--FILE--
+<?php
+
+$value = null;
+$value
+    |> fn ($x) => $x ?? throw new Exception('Value may not be null')
+    |> fn ($x) => var_dump($x);
+
+?>
+--EXPECTF--
+Fatal error: Arrow functions on the right hand side of |> must be parenthesized in %s on line %d

Zend/tests/pipe_operator/prec_007.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Pipe precedence 007
+--FILE--
+<?php
+
+$value = 42;
+$value
+    |> (fn ($x) => $x ?? throw new Exception('Value may not be null'))
+    |> (fn ($x) => var_dump($x));
+
+$value = null;
+$value
+    |> (fn ($x) => $x ?? throw new Exception('Value may not be null'))
+    |> (fn ($x) => var_dump($x));
+
+?>
+--EXPECTF--
+int(42)
+
+Fatal error: Uncaught Exception: Value may not be null in %s:%d
+Stack trace:
+#0 %s(%d): {closure:%s:%d}(NULL)
+#1 {main}
+  thrown in %s on line %d