Fixes #385, detection of side effects of ternary operator (#386)

src/rewriter.fs

@@ -24,6 +24,10 @@ let rec private sideEffects = function
         match fct.Declaration with
         | Declaration.UserFunction fd when not fd.hasExternallyVisibleSideEffects -> args |> List.collect sideEffects
         | _ -> [e]
+    | FunCall(Op "?:", [condExpr; thenExpr; elseExpr]) as e ->
+        if sideEffects thenExpr = [] && sideEffects elseExpr = []
+        then sideEffects condExpr
+        else [e] // We could apply sideEffects to thenExpr and elseExpr, but the result wouldn't necessarily have the same type...
     | FunCall(Op op, args) when not(Builtin.assignOps.Contains(op)) -> args |> List.collect sideEffects
     | FunCall(Dot(_, field) as e, args) when field = "length" -> (e :: args) |> List.collect sideEffects
     | FunCall(Subscript _ as e, args) -> (e :: args) |> List.collect sideEffects

tests/unit/ternary.frag

@@ -12,3 +12,18 @@ float f1() {
     a = true ? b = 2. : b = 3.;
     return a;
 }
+
+// Fix for #385
+
+out vec4 O;
+int k;
+void main() {
+  int d=0,e=0;
+  k==0 ? (sin(O.x),d=1) : (cos(O.x),e=2) ;
+  O.x=float(d);
+  O.y=float(e);
+}
+int f2() {
+  k++ == 0 ? 1 : 2 ;
+  return k;
+}

tests/unit/ternary.frag.expected

@@ -9,3 +9,19 @@ float f1()
   float a=1.;
   return a=2.;
 }
+out vec4 O;
+int k;
+void main()
+{
+  int d=0,e=0;
+  k==0?
+    (sin(O.x),d=1):
+    (cos(O.x),e=2);
+  O.x=float(d);
+  O.y=float(e);
+}
+int f2()
+{
+  k++;
+  return k;
+}