Fix unused variables and variable with a undefined value.

The latter isn't actually used anywhere before it's declared, and
an assert would enforce this, but it would still trigger a warning.
Now it's set to a value that's never used, and the assert has been
replaced with an exception so it can't be used in a release build
either. (optima.h)

src/interpreter/rank_order.cc

@@ -23,8 +23,6 @@ bool rank_order_int::is_this_format(const std::vector<std::string> &
 	// Possible todo later: more sophisticated checking, such as no rank
 	// symbols before a :.
 
-	int alnums_seen = 0;
-
 	for (size_t line = 0; line < inputs.size(); ++line) {
 		for (size_t sec = 0; sec < inputs[line].size(); ++sec) {
 			bool accepted = false;
@@ -43,7 +41,6 @@ bool rank_order_int::is_this_format(const std::vector<std::string> &
 				// "Write-In".
 				default:
 					if (isprint(inputs[line][sec])) {
-						++ alnums_seen;
 						accepted = true;
 					} else {
 						accepted = false;

src/main/test_strategy_brute_detail.cc

@@ -149,7 +149,7 @@ void test_strategy(std::shared_ptr<const election_method> to_test,
 	}
 
 
-	int strategy_worked = 0, strategy_failed = 0;
+	int strategy_worked = 0;
 	int i;
 	int total_test_attempts = 0;
 
@@ -161,8 +161,6 @@ void test_strategy(std::shared_ptr<const election_method> to_test,
 		// The total number of tests actually performed is retrieved later.
 		if (st.simulate(true) == 0) {
 			++strategy_worked;
-		} else {
-			++strategy_failed;
 		}
 
 		if ((i & 63) == 63) {

src/multiwinner/exhaustive/optima.h

@@ -32,6 +32,11 @@ class exhaustive_optima {
 		}
 
 		exhaustive_optima() {
+			// We have to set a maximization direction as otherwise
+			// it will count as an undefined value and may trip compiler
+			// warnings. However, we never use this direction since
+			// opt_direction_set is false.
+			maximize = false;
 			opt_direction_set = false;
 
 			minimum = std::numeric_limits<double>::signaling_NaN();
@@ -74,7 +79,10 @@ class exhaustive_optima {
 		}
 
 		std::vector<size_t> get_optimal_solution() const {
-			assert(opt_direction_set);
+			if (!opt_direction_set) {
+				throw std::runtime_error("Exhaustive optima: Init bug! No direction"
+					" of optimization has been set.");
+			}
 			if (maximize) {
 				return get_maximum_solution();
 			} else {

src/singlewinner/experimental/disqelim.cc

@@ -28,7 +28,6 @@ bool disqelim::disqualifies(int candidate,
 		power_set(continuing);
 
 	disqualified[candidate] = false;
-	int disqualifieds = count_trues(disqualified);
 
 	// For every subset of the continuing set:
 	//	if the candidate is not in it, skip.
@@ -106,7 +105,6 @@ bool disqelim::disqualifies(int candidate,
 			}
 
 			disqualified[saved_cand] = false;
-			--disqualifieds;
 
 			// TODO: Return early if we don't disqualify
 			// anyone; no need to test further.

src/singlewinner/gradual_c_b.cc

@@ -34,14 +34,6 @@ std::pair<ordering, bool> gradual_cond_borda::elect_inner(const
 	election_t & papers, const std::vector<bool> & hopefuls,
 	int num_candidates, cache_map * cache, bool winner_only) const {
 
-	size_t num_hopefuls = 0;
-
-	for (bool x: hopefuls) {
-		if (x) {
-			++num_hopefuls;
-		}
-	}
-
 	cond_borda_matrix gcb(papers, num_candidates, CM_PAIRWISE_OPP,
 		cardinal, completion);
 	condmat gcond(papers, num_candidates, CM_PAIRWISE_OPP);

src/singlewinner/gradual_c_b.h

@@ -12,6 +12,7 @@
 #include <glpk.h>
 #include <assert.h>
 
+// This code needs a review; I think it may be buggy.
 
 class gradual_cond_borda : public election_method {
 	private: