Fix parsing of large hex floats containing "e"

These ended up taking the code path for normal floats and being
cast to zero.

(cherry picked from commit 4ce9781)

Author: nikic

lib/PhpParser/Node/Scalar/DNumber.php

@@ -47,13 +47,7 @@ public static function fromString(string $str, array $attributes = []): DNumber
     public static function parse(string $str) : float {
         $str = str_replace('_', '', $str);
 
-        // if string contains any of .eE just cast it to float
-        if (false !== strpbrk($str, '.eE')) {
-            return (float) $str;
-        }
-
-        // otherwise it's an integer notation that overflowed into a float
-        // if it starts with 0 it's one of the special integer notations
+        // Check whether this is one of the special integer notations.
         if ('0' === $str[0]) {
             // hex
             if ('x' === $str[1] || 'X' === $str[1]) {
@@ -65,10 +59,12 @@ public static function parse(string $str) : float {
                 return bindec($str);
             }
 
-            // oct
-            // substr($str, 0, strcspn($str, '89')) cuts the string at the first invalid digit (8 or 9)
-            // so that only the digits before that are used
-            return octdec(substr($str, 0, strcspn($str, '89')));
+            // oct, but only if the string does not contain any of '.eE'.
+            if (false === strpbrk($str, '.eE')) {
+                // substr($str, 0, strcspn($str, '89')) cuts the string at the first invalid digit
+                // (8 or 9) so that only the digits before that are used.
+                return octdec(substr($str, 0, strcspn($str, '89')));
+            }
         }
 
         // dec

test/code/parser/scalar/float.test

@@ -17,6 +17,7 @@ Different float syntaxes
 // (all are actually the same number, just in different representations)
 18446744073709551615;
 0xFFFFFFFFFFFFFFFF;
+0xEEEEEEEEEEEEEEEE;
 01777777777777777777777;
 0177777777777777777777787;
 0b1111111111111111111111111111111111111111111111111111111111111111;
@@ -92,7 +93,7 @@ array(
     )
     12: Stmt_Expression(
         expr: Scalar_DNumber(
-            value: 1.844674407371E+19
+            value: 1.7216961135462E+19
         )
     )
     13: Stmt_Expression(
@@ -105,4 +106,9 @@ array(
             value: 1.844674407371E+19
         )
     )
-)
+    15: Stmt_Expression(
+        expr: Scalar_DNumber(
+            value: 1.844674407371E+19
+        )
+    )
+)