miniscript: nit: don't return after assert(false)

src/script/miniscript.cpp

@@ -245,7 +245,6 @@ Type ComputeType(Fragment fragment, Type x, Type y, Type z, const std::vector<Ty
             }
     }
     assert(false);
-    return ""_mst;
 }
 
 size_t ComputeScriptLen(Fragment fragment, Type sub0typ, size_t subsize, uint32_t k, size_t n_subs, size_t n_keys) {
@@ -278,7 +277,6 @@ size_t ComputeScriptLen(Fragment fragment, Type sub0typ, size_t subsize, uint32_
         case Fragment::THRESH: return subsize + n_subs + BuildScript(k).size();
     }
     assert(false);
-    return 0;
 }
 
 std::optional<std::vector<Opcode>> DecomposeScript(const CScript& script)

src/script/miniscript.h

@@ -532,7 +532,6 @@ public:
                 }
             }
             assert(false);
-            return {};
         };
         return TreeEval<CScript>(false, downfn, upfn);
     }
@@ -632,9 +631,9 @@ public:
                     }
                     return std::move(str) + ")";
                 }
-                default: assert(false);
+                default: break;
             }
-            return ""; // Should never be reached.
+            assert(false);
         };
 
         return TreeEvalMaybe<std::string>(false, downfn, upfn);
@@ -711,7 +710,6 @@ public:
             }
         }
         assert(false);
-        return {0, {}, {}};
     }
 
     internal::StackSize CalcStackSize() const {
@@ -762,7 +760,6 @@ public:
             }
         }
         assert(false);
-        return {{}, {}};
     }
 
     /** Check whether any key is repeated.