diff --git a/src/db-copy-mgr.hpp b/src/db-copy-mgr.hpp
index 7ec89492..cc545922 100644
--- a/src/db-copy-mgr.hpp
+++ b/src/db-copy-mgr.hpp
@@ -13,7 +13,7 @@ template <typename DELETER>
 class db_copy_mgr_t
 {
 public:
-    db_copy_mgr_t(std::shared_ptr<db_copy_thread_t> const &processor)
+    explicit db_copy_mgr_t(std::shared_ptr<db_copy_thread_t> const &processor)
     : m_processor(processor)
     {}
 
@@ -49,7 +49,7 @@ public:
 
         // Expect that a column has been written last which ended in a '\t'.
         // Replace it with the row delimiter '\n'.
-        auto sz = buf.size();
+        auto const sz = buf.size();
         assert(buf[sz - 1] == '\t');
         buf[sz - 1] = '\n';
 
@@ -67,7 +67,7 @@ public:
     void add_columns(T value, ARGS &&... args)
     {
         add_column(value);
-        add_columns(args...);
+        add_columns(std::forward<ARGS>(args)...);
     }
 
     template <typename T>
@@ -79,7 +79,7 @@ public:
     /**
      * Add a column entry of simple type.
      *
-     * Writes the column with the escaping apporpriate for the type and
+     * Writes the column with the escaping appropriate for the type and
      * a column delimiter.
      */
     template <typename T>
@@ -136,7 +136,7 @@ public:
      */
     void finish_array()
     {
-        auto idx = m_current->buffer.size() - 1;
+        auto const idx = m_current->buffer.size() - 1;
         if (m_current->buffer[idx] == '{')
             m_current->buffer += '}';
         else
@@ -222,7 +222,7 @@ public:
      */
     void finish_hash()
     {
-        auto idx = m_current->buffer.size() - 1;
+        auto const idx = m_current->buffer.size() - 1;
         if (!m_current->buffer.empty() && m_current->buffer[idx] == ',') {
             m_current->buffer[idx] = '\t';
         } else {
@@ -237,7 +237,7 @@ public:
      */
     void add_hex_geom(std::string const &wkb)
     {
-        char const *lookup_hex = "0123456789ABCDEF";
+        char const *const lookup_hex = "0123456789ABCDEF";
 
         for (char c : wkb) {
             m_current->buffer += lookup_hex[(c >> 4) & 0xf];
diff --git a/src/db-copy.hpp b/src/db-copy.hpp
index 3f2a756e..c6b3befd 100644
--- a/src/db-copy.hpp
+++ b/src/db-copy.hpp
@@ -225,7 +225,7 @@ struct db_cmd_finish_t : public db_cmd_t
 class db_copy_thread_t
 {
 public:
-    db_copy_thread_t(std::string const &conninfo);
+    explicit db_copy_thread_t(std::string const &conninfo);
 
     db_copy_thread_t(db_copy_thread_t const &) = delete;
     db_copy_thread_t &operator=(db_copy_thread_t const &) = delete;
diff --git a/src/domain-matcher.hpp b/src/domain-matcher.hpp
index 21041852..3eecf15e 100644
--- a/src/domain-matcher.hpp
+++ b/src/domain-matcher.hpp
@@ -6,7 +6,6 @@
 #include <cstring>
 #include <string>
 
-
 /**
  * Returns the tag specific name, if applicable.
  *
diff --git a/src/expire-tiles.cpp b/src/expire-tiles.cpp
index e28f613f..e88a346b 100644
--- a/src/expire-tiles.cpp
+++ b/src/expire-tiles.cpp
@@ -452,7 +452,7 @@ void expire_tiles::merge_and_destroy(expire_tiles &other)
                                      tile_width, other.tile_width)};
     }
 
-    if (m_dirty_tiles.size() == 0) {
+    if (m_dirty_tiles.empty()) {
         m_dirty_tiles = std::move(other.m_dirty_tiles);
     } else {
         m_dirty_tiles.insert(other.m_dirty_tiles.begin(),
diff --git a/src/gazetteer-style.cpp b/src/gazetteer-style.cpp
index 018c11ca..ab07bd32 100644
--- a/src/gazetteer-style.cpp
+++ b/src/gazetteer-style.cpp
@@ -17,7 +17,7 @@ enum : int
     MAX_ADMINLEVEL = 15
 };
 
-}
+} // anonymous namespace
 
 namespace pt = boost::property_tree;
 
diff --git a/src/id-tracker.cpp b/src/id-tracker.cpp
index ac9d7061..bceeae57 100644
--- a/src/id-tracker.cpp
+++ b/src/id-tracker.cpp
@@ -20,17 +20,17 @@ namespace {
  */
 struct block
 {
-    block() : bits(BLOCK_SIZE >> 5, 0) {}
+    block() : bits(BLOCK_SIZE >> 5U, 0) {}
     inline bool operator[](size_t i) const
     {
-        return (bits[i >> 5] & (1 << (i & 0x1f))) > 0;
+        return (bits[i >> 5U] & (1U << (i & 0x1fU))) > 0;
     }
     //returns true if the value actually caused a bit to flip
     inline bool set(size_t i, bool value)
     {
-        uint32_t &bit = bits[i >> 5];
+        uint32_t &bit = bits[i >> 5U];
         uint32_t old = bit;
-        uint32_t mask = 1 << (i & 0x1f);
+        uint32_t mask = 1U << (i & 0x1fU);
         //allow the bit to become 1 if not already
         if (value) {
             bit |= mask;
@@ -48,20 +48,20 @@ struct block
     // returns BLOCK_SIZE if a set bit isn't found
     size_t next_set(size_t start) const
     {
-        uint32_t bit_i = start >> 5;
+        uint32_t bit_i = start >> 5U;
 
-        while ((bit_i < (BLOCK_SIZE >> 5)) && (bits[bit_i] == 0)) {
+        while ((bit_i < (BLOCK_SIZE >> 5U)) && (bits[bit_i] == 0)) {
             ++bit_i;
         }
 
-        if (bit_i >= (BLOCK_SIZE >> 5)) {
+        if (bit_i >= (BLOCK_SIZE >> 5U)) {
             return BLOCK_SIZE;
         }
         uint32_t bit = bits[bit_i];
-        size_t idx = bit_i << 5;
-        while ((bit & 1) == 0) {
+        size_t idx = bit_i << 5U;
+        while ((bit & 1U) == 0) {
             ++idx;
-            bit >>= 1;
+            bit >>= 1U;
         }
         return idx;
     }
@@ -80,7 +80,7 @@ struct id_tracker::pimpl
     bool set(osmid_t id, bool value);
     osmid_t pop_min();
 
-    typedef std::map<osmid_t, block> map_t;
+    using map_t = std::map<osmid_t, block>;
     map_t pending;
     osmid_t old_id;
     size_t count;
@@ -92,21 +92,22 @@ struct id_tracker::pimpl
 
 bool id_tracker::pimpl::get(osmid_t id) const
 {
-    const osmid_t block = id >> BLOCK_BITS, offset = id & BLOCK_MASK;
-    map_t::const_iterator itr = pending.find(block);
-    bool result = false;
+    osmid_t const block = id >> BLOCK_BITS;
+    osmid_t const offset = id & BLOCK_MASK;
+    auto const itr = pending.find(block);
 
-    if (itr != pending.end()) {
-        result = itr->second[offset];
+    if (itr == pending.end()) {
+        return false;
     }
 
-    return result;
+    return itr->second[offset];
 }
 
 bool id_tracker::pimpl::set(osmid_t id, bool value)
 {
-    const osmid_t block = id >> BLOCK_BITS, offset = id & BLOCK_MASK;
-    bool flipped = pending[block].set(offset, value);
+    osmid_t const block = id >> BLOCK_BITS;
+    osmid_t const offset = id & BLOCK_MASK;
+    bool const flipped = pending[block].set(offset, value);
     // a set may potentially invalidate a next_start, as the bit
     // set might be before the position of next_start.
     if (next_start) {
diff --git a/src/middle-pgsql.cpp b/src/middle-pgsql.cpp
index 2338e418..558b8cdd 100644
--- a/src/middle-pgsql.cpp
+++ b/src/middle-pgsql.cpp
@@ -565,8 +565,8 @@ void middle_pgsql_t::relations_set(osmium::Relation const &rel)
 
     // parts
     m_db_copy.new_array();
-    for (int i = 0; i < 3; ++i) {
-        for (auto it : parts[i]) {
+    for (auto const &part : parts) {
+        for (auto it : part) {
             m_db_copy.add_array_elem(it);
         }
     }
@@ -813,9 +813,9 @@ middle_pgsql_t::get_query_instance(std::shared_ptr<middle_t> const &from) const
 
     // NOTE: this is thread safe for use in pending async processing only because
     // during that process they are only read from
-    std::unique_ptr<middle_query_pgsql_t> mid(new middle_query_pgsql_t(
-        src->out_options->database_options.conninfo().c_str(), src->cache,
-        src->persistent_cache));
+    std::unique_ptr<middle_query_pgsql_t> mid(new middle_query_pgsql_t{
+        src->out_options->database_options.conninfo(), src->cache,
+        src->persistent_cache});
 
     // We use a connection per table to enable the use of COPY
     for (int i = 0; i < NUM_TABLES; ++i) {
diff --git a/src/options.cpp b/src/options.cpp
index c520f994..d946ac9f 100644
--- a/src/options.cpp
+++ b/src/options.cpp
@@ -202,8 +202,9 @@ void long_usage(char *arg0, bool verbose = false)
                         pbf       - OSM binary format.\n\
        -O|--output      Output backend.\n\
                         pgsql - Output to a PostGIS database (default)\n\
+                        flex - More flexible output to PostGIS database\n\
                         multi - Multiple Custom Table Output to a PostGIS \n\
-                            database (requires style file for configuration)\n\
+                                database (deprecated)\n\
                         gazetteer - Output to a PostGIS database for Nominatim\n\
                         null - No output. Useful for testing. Still creates tables if --slim is specified.\n");
 #ifdef HAVE_LUA
@@ -345,7 +346,7 @@ options_t::options_t(int argc, char *argv[]) : options_t()
 #ifdef HAVE_GENERIC_PROJ
             projection = reprojection::create_projection(atoi(optarg));
 #else
-            throw std::runtime_error("Generic projections not available.");
+            throw std::runtime_error{"Generic projections not available."};
 #endif
             break;
         case 'p':
@@ -389,18 +390,18 @@ options_t::options_t(int argc, char *argv[]) : options_t()
             break;
         case 'e':
             if (!optarg || optarg[0] == '-') {
-                throw std::runtime_error(
+                throw std::runtime_error{
                     "Missing argument for option --expire-tiles. Zoom "
-                    "levels must be positive.\n");
+                    "levels must be positive.\n"};
             }
             char *next_char;
             expire_tiles_zoom_min =
                 static_cast<uint32_t>(std::strtoul(optarg, &next_char, 10));
             if (expire_tiles_zoom_min == 0) {
-                throw std::runtime_error(
+                throw std::runtime_error{
                     "Bad argument for option --expire-tiles. "
                     "Minimum zoom level must be larger "
-                    "than 0.\n");
+                    "than 0.\n"};
             }
             // The first character after the number is ignored because that is the separating hyphen.
             if (*next_char == '-') {
@@ -411,20 +412,20 @@ options_t::options_t(int argc, char *argv[]) : options_t()
                     expire_tiles_zoom = static_cast<uint32_t>(
                         std::strtoul(next_char, &after_maxzoom, 10));
                     if (expire_tiles_zoom == 0 || *after_maxzoom != '\0') {
-                        throw std::runtime_error("Invalid maximum zoom level "
-                                                 "given for tile expiry.\n");
+                        throw std::runtime_error{"Invalid maximum zoom level "
+                                                 "given for tile expiry.\n"};
                     }
                 } else {
-                    throw std::runtime_error(
-                        "Invalid maximum zoom level given for tile expiry.\n");
+                    throw std::runtime_error{
+                        "Invalid maximum zoom level given for tile expiry.\n"};
                 }
             } else if (*next_char == '\0') {
                 // end of string, no second zoom level given
                 expire_tiles_zoom = expire_tiles_zoom_min;
             } else {
-                throw std::runtime_error("Minimum and maximum zoom level for "
+                throw std::runtime_error{"Minimum and maximum zoom level for "
                                          "tile expiry must be separated by "
-                                         "'-'.\n");
+                                         "'-'.\n"};
             }
             break;
         case 'o':
@@ -446,8 +447,8 @@ options_t::options_t(int argc, char *argv[]) : options_t()
             break;
         case 'k':
             if (hstore_mode != HSTORE_NONE) {
-                throw std::runtime_error("You can not specify both --hstore "
-                                         "(-k) and --hstore-all (-j)\n");
+                throw std::runtime_error{"You can not specify both --hstore "
+                                         "(-k) and --hstore-all (-j)\n"};
             }
             hstore_mode = HSTORE_NORM;
             break;
@@ -456,13 +457,13 @@ options_t::options_t(int argc, char *argv[]) : options_t()
             break;
         case 'j':
             if (hstore_mode != HSTORE_NONE) {
-                throw std::runtime_error("You can not specify both --hstore "
-                                         "(-k) and --hstore-all (-j)\n");
+                throw std::runtime_error{"You can not specify both --hstore "
+                                         "(-k) and --hstore-all (-j)\n"};
             }
             hstore_mode = HSTORE_ALL;
             break;
         case 'z':
-            hstore_columns.push_back(optarg);
+            hstore_columns.emplace_back(optarg);
             break;
         case 'G':
             enable_multi = true;
@@ -477,13 +478,13 @@ options_t::options_t(int argc, char *argv[]) : options_t()
             parallel_indexing = false;
             break;
         case 204:
-            if (strcmp(optarg, "dense") == 0) {
+            if (std::strcmp(optarg, "dense") == 0) {
                 alloc_chunkwise = ALLOC_DENSE;
-            } else if (strcmp(optarg, "chunk") == 0) {
+            } else if (std::strcmp(optarg, "chunk") == 0) {
                 alloc_chunkwise = ALLOC_DENSE | ALLOC_DENSE_CHUNK;
-            } else if (strcmp(optarg, "sparse") == 0) {
+            } else if (std::strcmp(optarg, "sparse") == 0) {
                 alloc_chunkwise = ALLOC_SPARSE;
-            } else if (strcmp(optarg, "optimized") == 0) {
+            } else if (std::strcmp(optarg, "optimized") == 0) {
                 alloc_chunkwise = ALLOC_DENSE | ALLOC_SPARSE;
             } else {
                 throw std::runtime_error{
@@ -543,7 +544,7 @@ options_t::options_t(int argc, char *argv[]) : options_t()
 
     //get the input files
     while (optind < argc) {
-        input_files.push_back(std::string(argv[optind]));
+        input_files.emplace_back(argv[optind]);
         optind++;
     }
 
@@ -566,19 +567,19 @@ options_t::options_t(int argc, char *argv[]) : options_t()
 void options_t::check_options()
 {
     if (append && create) {
-        throw std::runtime_error("--append and --create options can not be "
-                                 "used at the same time!\n");
+        throw std::runtime_error{"--append and --create options can not be "
+                                 "used at the same time!\n"};
     }
 
     if (append && !slim) {
-        throw std::runtime_error("--append can only be used with slim mode!\n");
+        throw std::runtime_error{"--append can only be used with slim mode!\n"};
     }
 
     if (droptemp && !slim) {
-        throw std::runtime_error("--drop only makes sense with --slim.\n");
+        throw std::runtime_error{"--drop only makes sense with --slim.\n"};
     }
 
-    if (hstore_mode == HSTORE_NONE && hstore_columns.size() == 0 &&
+    if (hstore_mode == HSTORE_NONE && hstore_columns.empty() &&
         hstore_match_only) {
         fprintf(stderr,
                 "Warning: --hstore-match-only only makes sense with --hstore, "
@@ -587,7 +588,7 @@ void options_t::check_options()
     }
 
     if (enable_hstore_index && hstore_mode == HSTORE_NONE &&
-        hstore_columns.size() == 0) {
+        hstore_columns.empty()) {
         fprintf(stderr, "Warning: --hstore-add-index only makes sense with "
                         "hstore enabled.\n");
         enable_hstore_index = false;
@@ -601,8 +602,8 @@ void options_t::check_options()
 
     if (cache == 0) {
         if (!slim) {
-            throw std::runtime_error(
-                "Ram node cache can only be disable in slim mode.\n");
+            throw std::runtime_error{
+                "Ram node cache can only be disable in slim mode.\n"};
         }
         if (!flat_node_cache_enabled) {
             fprintf(stderr, "WARNING: ram cache is disabled. This will likely "
diff --git a/src/osm2pgsql.cpp b/src/osm2pgsql.cpp
index 48ea2e06..9651de2c 100644
--- a/src/osm2pgsql.cpp
+++ b/src/osm2pgsql.cpp
@@ -87,7 +87,7 @@ int main(int argc, char *argv[])
          */
         parse_stats_t stats;
         //read in the input files one by one
-        for (auto const filename : options.input_files) {
+        for (auto const &filename : options.input_files) {
             //read the actual input
             fprintf(stderr, "\nReading in file: %s\n", filename.c_str());
             time_t start = time(nullptr);
diff --git a/src/osmdata.cpp b/src/osmdata.cpp
index 77bec1f3..c9b84f90 100644
--- a/src/osmdata.cpp
+++ b/src/osmdata.cpp
@@ -245,7 +245,7 @@ struct pending_threaded_processor : public middle_t::pending_processor
 
     ~pending_threaded_processor() {}
 
-    void enqueue_ways(osmid_t id)
+    void enqueue_ways(osmid_t id) override
     {
         for (size_t i = 0; i < outs.size(); ++i) {
             outs[i]->enqueue_ways(queue, id, i, ids_queued);
@@ -253,7 +253,7 @@ struct pending_threaded_processor : public middle_t::pending_processor
     }
 
     //waits for the completion of all outstanding jobs
-    void process_ways()
+    void process_ways() override
     {
         //reset the number we've done
         ids_done = 0;
@@ -315,14 +315,14 @@ struct pending_threaded_processor : public middle_t::pending_processor
         }
     }
 
-    void enqueue_relations(osmid_t id)
+    void enqueue_relations(osmid_t id) override
     {
         for (size_t i = 0; i < outs.size(); ++i) {
             outs[i]->enqueue_relations(queue, id, i, ids_queued);
         }
     }
 
-    void process_relations()
+    void process_relations() override
     {
         //reset the number we've done
         ids_done = 0;
diff --git a/src/osmium-builder.cpp b/src/osmium-builder.cpp
index 655970de..c06cf224 100644
--- a/src/osmium-builder.cpp
+++ b/src/osmium-builder.cpp
@@ -378,28 +378,28 @@ osmium_builder_t::create_polygons(osmium::Area const &area)
     try {
         size_t num_rings = 0;
 
-        for (auto it = area.cbegin(); it != area.cend(); ++it) {
-            if (it->type() == osmium::item_type::outer_ring) {
-                auto &ring = static_cast<const osmium::OuterRing &>(*it);
+        for (const auto &item : area) {
+            if (item.type() == osmium::item_type::outer_ring) {
+                auto const &ring = static_cast<const osmium::OuterRing &>(item);
                 if (num_rings > 0) {
                     ret.push_back(m_writer.polygon_finish(num_rings));
                     num_rings = 0;
                 }
                 m_writer.polygon_start();
                 m_writer.polygon_ring_start();
-                auto num_points = add_mp_points(ring);
+                auto const num_points = add_mp_points(ring);
                 m_writer.polygon_ring_finish(num_points);
                 ++num_rings;
-            } else if (it->type() == osmium::item_type::inner_ring) {
-                auto &ring = static_cast<const osmium::InnerRing &>(*it);
+            } else if (item.type() == osmium::item_type::inner_ring) {
+                auto const &ring = static_cast<const osmium::InnerRing &>(item);
                 m_writer.polygon_ring_start();
-                auto num_points = add_mp_points(ring);
+                auto const num_points = add_mp_points(ring);
                 m_writer.polygon_ring_finish(num_points);
                 ++num_rings;
             }
         }
 
-        auto wkb = m_writer.polygon_finish(num_rings);
+        auto const wkb = m_writer.polygon_finish(num_rings);
         if (num_rings > 0) {
             ret.push_back(wkb);
         }
diff --git a/src/osmtypes.hpp b/src/osmtypes.hpp
index cb920c8f..08bf4670 100644
--- a/src/osmtypes.hpp
+++ b/src/osmtypes.hpp
@@ -18,7 +18,7 @@
 #include <osmium/geom/coordinates.hpp>
 #include <osmium/osm.hpp>
 
-typedef int64_t osmid_t;
+using osmid_t = std::int64_t;
 #define strtoosmid strtoll
 #define PRIdOSMID PRId64
 #define POSTGRES_OSMID_TYPE "int8"
diff --git a/src/output-flex.cpp b/src/output-flex.cpp
index 04d6489e..081227be 100644
--- a/src/output-flex.cpp
+++ b/src/output-flex.cpp
@@ -913,8 +913,8 @@ void output_flex_t::pending_way(osmid_t id, int exists)
     if (exists) {
         way_delete(id);
         auto const rel_ids = m_mid->relations_using_way(id);
-        for (auto const id : rel_ids) {
-            m_rels_pending_tracker.mark(id);
+        for (auto const rel_id : rel_ids) {
+            m_rels_pending_tracker.mark(rel_id);
         }
     }
 
diff --git a/src/output-multi.cpp b/src/output-multi.cpp
index 0a83fae1..47ee4c56 100644
--- a/src/output-multi.cpp
+++ b/src/output-multi.cpp
@@ -212,7 +212,7 @@ void output_multi_t::relation_add(osmium::Relation const &rel)
 {
     if (m_processor->interests(geometry_processor::interest_relation) &&
         !rel.members().empty()) {
-        process_relation(rel, 0);
+        process_relation(rel, false);
     }
 }
 
@@ -299,11 +299,9 @@ void output_multi_t::reprocess_way(osmium::Way *way, bool exists)
     if (m_processor->interests(geometry_processor::interest_relation) &&
         exists) {
         way_delete(way->id());
-        const std::vector<osmid_t> rel_ids =
-            m_mid->relations_using_way(way->id());
-        for (std::vector<osmid_t>::const_iterator itr = rel_ids.begin();
-             itr != rel_ids.end(); ++itr) {
-            rels_pending_tracker.mark(*itr);
+        auto const rel_ids = m_mid->relations_using_way(way->id());
+        for (auto const rel_id : rel_ids) {
+            rels_pending_tracker.mark(rel_id);
         }
     }
 
@@ -382,7 +380,7 @@ void output_multi_t::process_relation(osmium::Relation const &rel, bool exists)
             m_relation_helper.add_way_locations(m_mid.get());
             auto geoms = m_processor->process_relation(
                 rel, m_relation_helper.data, &m_builder);
-            for (const auto geom : geoms) {
+            for (const auto &geom : geoms) {
                 copy_to_table(-rel.id(), geom, outtags);
             }
         }
diff --git a/src/pgsql.hpp b/src/pgsql.hpp
index fa8fb61b..df571f20 100644
--- a/src/pgsql.hpp
+++ b/src/pgsql.hpp
@@ -64,14 +64,15 @@ public:
      */
     std::string get_value_as_string(int row, int col) const noexcept
     {
-        return std::string(get_value(row, col), (std::size_t)get_length(row, col));
+        return std::string(get_value(row, col),
+                           (std::size_t)get_length(row, col));
     }
 
     /**
      * Get the column number from the name. Returns -1 if there is no column
      * of that name.
      */
-    int get_column_number(std::string const& name) const noexcept
+    int get_column_number(std::string const &name) const noexcept
     {
         return PQfnumber(m_result.get(), ('"' + name + '"').c_str());
     }
diff --git a/src/processor-polygon.hpp b/src/processor-polygon.hpp
index f4ac6fbd..c6ac7794 100644
--- a/src/processor-polygon.hpp
+++ b/src/processor-polygon.hpp
@@ -14,6 +14,7 @@ public:
     wkbs_t process_relation(osmium::Relation const &rel,
                             osmium::memory::Buffer const &ways,
                             geom::osmium_builder_t *builder) override;
+
 private:
     bool m_build_multigeoms;
 };
diff --git a/src/reprojection-generic-none.cpp b/src/reprojection-generic-none.cpp
index f41d7b7f..30998ef3 100644
--- a/src/reprojection-generic-none.cpp
+++ b/src/reprojection-generic-none.cpp
@@ -4,5 +4,5 @@
 
 std::shared_ptr<reprojection> reprojection::make_generic_projection(int srs)
 {
-    throw std::runtime_error("No generic projection library available.");
+    throw std::runtime_error{"No generic projection library available."};
 }
diff --git a/src/reprojection-generic-proj4.cpp b/src/reprojection-generic-proj4.cpp
index 76da085b..4c739c75 100644
--- a/src/reprojection-generic-proj4.cpp
+++ b/src/reprojection-generic-proj4.cpp
@@ -10,7 +10,7 @@ namespace {
 class generic_reprojection_t : public reprojection
 {
 public:
-    generic_reprojection_t(int srs)
+    explicit generic_reprojection_t(int srs)
     : m_target_srs(srs), pj_target(srs), pj_source(PROJ_LATLONG),
       pj_tile(
           "+proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 "
@@ -58,5 +58,5 @@ private:
 
 std::shared_ptr<reprojection> reprojection::make_generic_projection(int srs)
 {
-    return std::shared_ptr<reprojection>(new generic_reprojection_t(srs));
+    return std::shared_ptr<reprojection>(new generic_reprojection_t{srs});
 }
diff --git a/src/table.cpp b/src/table.cpp
index c9da8787..331a165c 100644
--- a/src/table.cpp
+++ b/src/table.cpp
@@ -24,7 +24,7 @@ table_t::table_t(std::string const &name, std::string const &type,
   m_copy(copy_thread)
 {
     // if we dont have any columns
-    if (columns.size() == 0 && hstore_mode != HSTORE_ALL) {
+    if (columns.empty() && hstore_mode != HSTORE_ALL) {
         throw std::runtime_error{
             "No columns provided for table {}"_format(name)};
     }
@@ -450,13 +450,13 @@ void table_t::escape_type(const std::string &value, ColumnType flags)
             int items = sscanf(escaped.c_str(), "%lf-%lf", &from, &to);
             if (items == 1) {
                 if (escaped.size() > 1 &&
-                    escaped.substr(escaped.size() - 2).compare("ft") == 0) {
+                    escaped.substr(escaped.size() - 2) == "ft") {
                     from *= 0.3048;
                 }
                 m_copy.add_column(from);
             } else if (items == 2) {
                 if (escaped.size() > 1 &&
-                    escaped.substr(escaped.size() - 2).compare("ft") == 0) {
+                    escaped.substr(escaped.size() - 2) == "ft") {
                     from *= 0.3048;
                     to *= 0.3048;
                 }
diff --git a/src/tagtransform-c.cpp b/src/tagtransform-c.cpp
index e798db65..d9c8018c 100644
--- a/src/tagtransform-c.cpp
+++ b/src/tagtransform-c.cpp
@@ -35,12 +35,12 @@ static const unsigned int nLayers = (sizeof(layers) / sizeof(*layers));
 
 void add_z_order(taglist_t &tags, int *roads)
 {
-    const std::string *layer = tags.get("layer");
-    const std::string *highway = tags.get("highway");
-    bool bridge = tags.get_bool("bridge", false);
-    bool tunnel = tags.get_bool("tunnel", false);
-    const std::string *railway = tags.get("railway");
-    const std::string *boundary = tags.get("boundary");
+    std::string const *const layer = tags.get("layer");
+    std::string const *const highway = tags.get("highway");
+    bool const bridge = tags.get_bool("bridge", false);
+    bool const tunnel = tags.get_bool("tunnel", false);
+    std::string const *const railway = tags.get("railway");
+    std::string const *const boundary = tags.get("boundary");
 
     int z_order = 0;
 
@@ -90,7 +90,7 @@ c_tagtransform_t::c_tagtransform_t(options_t const *options,
 std::unique_ptr<tagtransform_t> c_tagtransform_t::clone() const
 {
     return std::unique_ptr<tagtransform_t>(
-        new c_tagtransform_t(m_options, m_export_list));
+        new c_tagtransform_t{m_options, m_export_list});
 }
 
 bool c_tagtransform_t::check_key(std::vector<taginfo> const &infos,
@@ -98,14 +98,12 @@ bool c_tagtransform_t::check_key(std::vector<taginfo> const &infos,
                                  bool strict)
 {
     //go through the actual tags found on the item and keep the ones in the export list
-    size_t i = 0;
-    for (; i < infos.size(); i++) {
-        const taginfo &info = infos[i];
+    for (auto const &info : infos) {
         if (info.flags & FLAG_DELETE) {
             if (wildMatch(info.name.c_str(), k)) {
                 return false;
             }
-        } else if (strcmp(info.name.c_str(), k) == 0) {
+        } else if (std::strcmp(info.name.c_str(), k) == 0) {
             *filter = false;
             *flags |= info.flags;
 
@@ -124,11 +122,10 @@ bool c_tagtransform_t::check_key(std::vector<taginfo> const &infos,
             }
             /* with hstore, copy all tags... */
             return true;
-        } else if (m_options->hstore_columns.size() > 0) {
+        } else if (!m_options->hstore_columns.empty()) {
             /* does this column match any of the hstore column prefixes? */
-            size_t j = 0;
-            for (; j < m_options->hstore_columns.size(); ++j) {
-                if (boost::starts_with(k, m_options->hstore_columns[j])) {
+            for (auto const &column : m_options->hstore_columns) {
+                if (boost::starts_with(k, column)) {
                     /* ... but if hstore_match_only is set then don't take this
                          as a reason for keeping the object */
                     if (!m_options->hstore_match_only) {
@@ -156,23 +153,24 @@ bool c_tagtransform_t::filter_tags(osmium::OSMObject const &o, int *polygon,
     if (o.type() == osmium::item_type::relation) {
         export_type = osmium::item_type::way;
     }
-    const std::vector<taginfo> &infos = m_export_list.get(export_type);
+    auto const &infos = m_export_list.get(export_type);
 
     /* We used to only go far enough to determine if it's a polygon or not,
        but now we go through and filter stuff we don't need
        pop each tag off and keep it in the temp list if we like it */
     for (auto const &item : o.tags()) {
-        char const *k = item.key();
-        char const *v = item.value();
+        char const *const k = item.key();
+        char const *const v = item.value();
         //if we want to do more than the export list says
         if (!strict) {
             if (o.type() == osmium::item_type::relation &&
-                strcmp("type", k) == 0) {
+                std::strcmp("type", k) == 0) {
                 out_tags.add_tag(k, v);
                 continue;
             }
             /* Allow named islands to appear as polygons */
-            if (strcmp("natural", k) == 0 && strcmp("coastline", v) == 0) {
+            if (std::strcmp("natural", k) == 0 &&
+                std::strcmp("coastline", v) == 0) {
                 add_area_tag = 1;
 
                 /* Discard natural=coastline tags (we render these from a shapefile instead) */
@@ -219,7 +217,7 @@ bool c_tagtransform_t::filter_rel_member_tags(
     taglist_t &out_tags, bool allow_typeless)
 {
     //if it has a relation figure out what kind it is
-    const std::string *type = rel_tags.get("type");
+    std::string const *type = rel_tags.get("type");
     bool is_route = false, is_boundary = false, is_multipolygon = false;
     if (type) {
         //what kind of relation is it
@@ -238,7 +236,7 @@ bool c_tagtransform_t::filter_rel_member_tags(
     }
 
     /* Clone tags from relation */
-    for (const auto &rel_tag : rel_tags) {
+    for (auto const &rel_tag : rel_tags) {
         //copy the name tag as "route_name"
         if (is_route && (rel_tag.key == "name")) {
             out_tags.add_tag_if_not_exists("route_name", rel_tag.value);
@@ -254,11 +252,11 @@ bool c_tagtransform_t::filter_rel_member_tags(
     }
 
     if (is_route) {
-        const std::string *netw = rel_tags.get("network");
+        std::string const *netw = rel_tags.get("network");
         int networknr = -1;
 
         if (netw != nullptr) {
-            const std::string *state = rel_tags.get("state");
+            std::string const *state = rel_tags.get("state");
             std::string statetype("yes");
             if (state) {
                 if (*state == "alternate") {
@@ -288,7 +286,7 @@ bool c_tagtransform_t::filter_rel_member_tags(
             }
         }
 
-        const std::string *prefcol = rel_tags.get("preferred_color");
+        std::string const *prefcol = rel_tags.get("preferred_color");
         if (prefcol != nullptr && prefcol->size() == 1) {
             if ((*prefcol)[0] == '0' || (*prefcol)[0] == '1' ||
                 (*prefcol)[0] == '2' || (*prefcol)[0] == '3' ||
@@ -301,7 +299,7 @@ bool c_tagtransform_t::filter_rel_member_tags(
             out_tags.add_tag_if_not_exists("route_pref_color", "0");
         }
 
-        const std::string *relref = rel_tags.get("ref");
+        std::string const *relref = rel_tags.get("ref");
         if (relref != nullptr) {
             if (networknr == 10) {
                 out_tags.add_tag_if_not_exists("lcn_ref", *relref);
diff --git a/tests/test-db-copy-mgr.cpp b/tests/test-db-copy-mgr.cpp
index 3b3e82ba..9d6bdedf 100644
--- a/tests/test-db-copy-mgr.cpp
+++ b/tests/test-db-copy-mgr.cpp
@@ -43,7 +43,7 @@ void add_array(copy_mgr_t &mgr, std::shared_ptr<db_target_descr_t> t, int id,
     mgr.new_line(t);
     mgr.add_column(id);
     mgr.new_array();
-    for (auto v : values) {
+    for (auto const &v : values) {
         mgr.add_array_elem(v);
     }
     mgr.finish_array();
diff --git a/tests/test-expire-tiles.cpp b/tests/test-expire-tiles.cpp
index fe90fd84..35bff742 100644
--- a/tests/test-expire-tiles.cpp
+++ b/tests/test-expire-tiles.cpp
@@ -14,12 +14,12 @@ class xyz
 public:
     xyz(uint32_t z_, int64_t x_, int64_t y_) : z(z_), x(x_), y(y_) {}
 
-    bool operator==(xyz const &other) const
+    bool operator==(xyz const &other) const noexcept
     {
         return ((z == other.z) && (x == other.x) && (y == other.y));
     }
 
-    bool operator<(xyz const &other) const
+    bool operator<(xyz const &other) const noexcept
     {
         if (z < other.z) {
             return true;
@@ -40,7 +40,7 @@ public:
         return false;
     }
 
-    void to_centroid(double &cx, double &cy) const
+    void to_centroid(double &cx, double &cy) const noexcept
     {
         double const datum = 0.5 * (1U << z);
         double const scale = EARTH_CIRCUMFERENCE / (1U << z);
@@ -55,8 +55,6 @@ private:
 
 struct tile_output_set
 {
-    ~tile_output_set() = default;
-
     bool operator==(tile_output_set const &other) const
     {
         return tiles == other.tiles;
@@ -70,7 +68,7 @@ struct tile_output_set
 
     void output_dirty_tile(int64_t x, int64_t y, uint32_t zoom)
     {
-        tiles.insert(xyz(zoom, x, y));
+        tiles.insert(xyz{zoom, x, y});
     }
 
     void expire_centroids(expire_tiles &et)