Revert "A special state to track field selection is not necessary."

src/compiler/translator/glslang.l

@@ -70,6 +70,7 @@ static int floatsuffix_check(TParseContext* context);
 %option noyywrap nounput never-interactive
 %option yylineno reentrant bison-bridge bison-locations
 %option extra-type="TParseContext*"
+%x FIELDS
 
 D           [0-9]
 L           [a-zA-Z_]
@@ -358,7 +359,7 @@ O           [0-7]
 ")"             { return RIGHT_PAREN; }
 ("["|"<:")      { return LEFT_BRACKET; }
 ("]"|":>")      { return RIGHT_BRACKET; }
-"."             { return DOT; }
+"."             { BEGIN(FIELDS); return DOT; }
 "!"             { return BANG; }
 "-"             { return DASH; }
 "~"             { return TILDE; }
@@ -373,9 +374,16 @@ O           [0-7]
 "&"             { return AMPERSAND; }
 "?"             { return QUESTION; }
 
+<FIELDS>{L}({L}|{D})* {
+    BEGIN(INITIAL);
+    yylval->lex.string = NewPoolTString(yytext);
+    return FIELD_SELECTION;
+}
+<FIELDS>[ \t\v\f\r] {}
+
 [ \t\v\n\f\r] { }
-<<EOF>>       { yyterminate(); }
-.             { assert(false); return 0; }
+<*><<EOF>>    { yyterminate(); }
+<*>.          { assert(false); return 0; }
 
 %%
 

src/compiler/translator/glslang.y

@@ -272,7 +272,7 @@ postfix_expression
     | function_call {
         $$ = $1;
     }
-    | postfix_expression DOT identifier {
+    | postfix_expression DOT FIELD_SELECTION {
         $$ = context->addFieldSelectionExpression($1, @2, *$3.string, @3);
     }
     | postfix_expression INC_OP {
@@ -367,6 +367,13 @@ function_identifier
         TFunction *function = new TFunction($1.string, type);
         $$ = function;
     }
+    | FIELD_SELECTION {
+        if (context->reservedErrorCheck(@1, *$1.string))
+            context->recover();
+        TType type(EbtVoid, EbpUndefined);
+        TFunction *function = new TFunction($1.string, type);
+        $$ = function;
+    }
     ;
 
 unary_expression