diff --git a/NEWS b/NEWS
index 3467754039c..d4354c12b08 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,7 @@ PHP                                                                        NEWS
   . Fixed bug GH-18907 (Leak when creating cycle in hook). (ilutov)
   . Fix OSS-Fuzz #427814456. (nielsdos)
   . Fix OSS-Fuzz #428983568 and #428760800. (nielsdos)
+  . Fixed bug GH-17204 -Wuseless-escape warnings emitted by re2c. (Peter Kokot)
 
 - Curl:
   . Fix memory leaks when returning refcounted value from curl callback.
diff --git a/Zend/zend_ini_scanner.l b/Zend/zend_ini_scanner.l
index 44159297a04..b87f4e33cc8 100644
--- a/Zend/zend_ini_scanner.l
+++ b/Zend/zend_ini_scanner.l
@@ -352,16 +352,16 @@ restart:
 /*!re2c
 re2c:yyfill:check = 0;
 LNUM [0-9]+
-DNUM ([0-9]*[\.][0-9]+)|([0-9]+[\.][0-9]*)
+DNUM ([0-9]*[.][0-9]+)|([0-9]+[.][0-9]*)
 NUMBER [-]?{LNUM}|{DNUM}
 ANY_CHAR (.|[\n\t])
 NEWLINE	("\r"|"\n"|"\r\n")
 TABS_AND_SPACES [ \t]
 WHITESPACE [ \t]+
 CONSTANT [a-zA-Z_][a-zA-Z0-9_]*
-LABEL_CHAR [^=\n\r\t;&|^$~(){}!"\[\]\x00]
+LABEL_CHAR [^=\n\r\t;&|^$~(){}!"[\]\x00]
 LABEL ({LABEL_CHAR}+)
-TOKENS [:,.\[\]"'()&|^+-/*=%$!~<>?@{}]
+TOKENS [:,.[\]"'()&|^+-/*=%$!~<>?@{}]
 OPERATORS [&|^~()!]
 DOLLAR_CURLY "${"
 
diff --git a/Zend/zend_language_scanner.l b/Zend/zend_language_scanner.l
index 7ae73875926..988ec6366a7 100644
--- a/Zend/zend_language_scanner.l
+++ b/Zend/zend_language_scanner.l
@@ -1813,11 +1813,11 @@ OPTIONAL_WHITESPACE_OR_COMMENTS ({WHITESPACE}|{MULTI_LINE_COMMENT}|{SINGLE_LINE_
 	RETURN_TOKEN(T_MUL_EQUAL);
 }
 
-<ST_IN_SCRIPTING>"*\*" {
+<ST_IN_SCRIPTING>"**" {
 	RETURN_TOKEN(T_POW);
 }
 
-<ST_IN_SCRIPTING>"*\*=" {
+<ST_IN_SCRIPTING>"**=" {
 	RETURN_TOKEN(T_POW_EQUAL);
 }
 
diff --git a/sapi/phpdbg/phpdbg_lexer.l b/sapi/phpdbg/phpdbg_lexer.l
index 60d995526ea..ba1423c5a4e 100644
--- a/sapi/phpdbg/phpdbg_lexer.l
+++ b/sapi/phpdbg/phpdbg_lexer.l
@@ -77,7 +77,7 @@ T_IF        'if'
 T_RUN       'run'
 T_RUN_SHORT "r"
 WS          [ \r\t]+
-DIGITS      [-]?[0-9\.]+
+DIGITS      [-]?[0-9.]+
 ID          [^ \r\n\t:#\000]+
 GENERIC_ID  ([^ \r\n\t:#\000"']|":\\")+|["]([^\n\000"\\]|"\\\\"|"\\"["])+["]|[']([^\n\000'\\]|"\\\\"|"\\"['])+[']
 ADDR        [0][x][a-fA-F0-9]+