Fix lint errs (#59)

vendor/honnef.co/go/tools/ssautil/ssautil.go

@@ -0,0 +1,41 @@
+package ssautil
+
+import (
+	"honnef.co/go/tools/ssa"
+)
+
+func Reachable(from, to *ssa.BasicBlock) bool {
+	if from == to {
+		return true
+	}
+	if from.Dominates(to) {
+		return true
+	}
+
+	found := false
+	Walk(from, func(b *ssa.BasicBlock) bool {
+		if b == to {
+			found = true
+			return false
+		}
+		return true
+	})
+	return found
+}
+
+func Walk(b *ssa.BasicBlock, fn func(*ssa.BasicBlock) bool) {
+	seen := map[*ssa.BasicBlock]bool{}
+	wl := []*ssa.BasicBlock{b}
+	for len(wl) > 0 {
+		b := wl[len(wl)-1]
+		wl = wl[:len(wl)-1]
+		if seen[b] {
+			continue
+		}
+		seen[b] = true
+		if !fn(b) {
+			continue
+		}
+		wl = append(wl, b.Succs...)
+	}
+}