diff --git a/.github/workflows/CI-mingw.yml b/.github/workflows/CI-mingw.yml
index b5c067dc7..75de79ed1 100644
--- a/.github/workflows/CI-mingw.yml
+++ b/.github/workflows/CI-mingw.yml
@@ -47,6 +47,7 @@ jobs:
         with:
           key: ${{ github.workflow }}-${{ github.job }}-${{ matrix.os }}
 
+      # TODO: bail out on warning
       - name: Build cppcheck
         run: |
           export PATH="/mingw64/lib/ccache/bin:$PATH"
diff --git a/.github/workflows/CI-unixish-docker.yml b/.github/workflows/CI-unixish-docker.yml
index 9bfc5a017..c8095c54a 100644
--- a/.github/workflows/CI-unixish-docker.yml
+++ b/.github/workflows/CI-unixish-docker.yml
@@ -135,13 +135,13 @@ jobs:
         run: |
           # "/usr/lib64" for centos / "/usr/lib" for ubuntu
           export PATH="/usr/lib64/ccache:/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
-          make -j$(nproc) HAVE_RULES=yes
+          make -j$(nproc) HAVE_RULES=yes CXXFLAGS="-w"
 
       - name: Build test
         run: |
           # "/usr/lib64" for centos / "/usr/lib" for ubuntu
           export PATH="/usr/lib64/ccache:/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
-          make -j$(nproc) testrunner HAVE_RULES=yes
+          make -j$(nproc) testrunner HAVE_RULES=yes CXXFLAGS="-w"
 
       - name: Run test
         run: |
diff --git a/.github/workflows/CI-unixish.yml b/.github/workflows/CI-unixish.yml
index b2d35df36..9f80c4500 100644
--- a/.github/workflows/CI-unixish.yml
+++ b/.github/workflows/CI-unixish.yml
@@ -450,7 +450,7 @@ jobs:
         run: |
           export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
           # compile with verification and ast matchers
-          make -j$(nproc) -s CPPFLAGS="-DCHECK_INTERNAL" CXXFLAGS="-g -O2 -DHAVE_BOOST" MATCHCOMPILER=yes VERIFY=1
+          make -j$(nproc) -s CPPFLAGS="-DCHECK_INTERNAL" CXXFLAGS="-g -O2 -w -DHAVE_BOOST" MATCHCOMPILER=yes VERIFY=1
 
       - name: Generate UI files
         run: |
diff --git a/.github/workflows/asan.yml b/.github/workflows/asan.yml
index 428528e4a..e57ac201d 100644
--- a/.github/workflows/asan.yml
+++ b/.github/workflows/asan.yml
@@ -59,6 +59,7 @@ jobs:
           modules: 'qtcharts'
           cache: true
 
+      # TODO: disable all warnings
       - name: CMake
         run: |
           cmake -S . -B cmake.output -DCMAKE_BUILD_TYPE=RelWithDebInfo -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=Off -DWITH_QCHART=Off -DUSE_MATCHCOMPILER=Verify -DANALYZE_ADDRESS=On -DENABLE_CHECK_INTERNAL=On -DUSE_BOOST=On -DCPPCHK_GLIBCXX_DEBUG=Off -DCMAKE_DISABLE_PRECOMPILE_HEADERS=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=Off -DDISABLE_DMAKE=On -DCMAKE_C_COMPILER_LAUNCHER=ccache -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
diff --git a/.github/workflows/scriptcheck.yml b/.github/workflows/scriptcheck.yml
index d7e78896f..627cff4af 100644
--- a/.github/workflows/scriptcheck.yml
+++ b/.github/workflows/scriptcheck.yml
@@ -37,7 +37,7 @@ jobs:
       - name: build cppcheck
         run: |
           export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
-          make -j$(nproc) -s
+          make -j$(nproc) -s CXXFLAGS="-w"
           strip -s ./cppcheck
 
   scriptcheck:
@@ -183,5 +183,5 @@ jobs:
       - name: dmake
         if: matrix.python-latest
         run: |
-          make -j$(nproc) run-dmake
+          make -j$(nproc) CXXFLAGS="-w" run-dmake
           git diff --exit-code
diff --git a/.github/workflows/ubsan.yml b/.github/workflows/ubsan.yml
index 335edbd62..cf6333b04 100644
--- a/.github/workflows/ubsan.yml
+++ b/.github/workflows/ubsan.yml
@@ -58,6 +58,7 @@ jobs:
           modules: 'qtcharts'
           cache: true
 
+      # TODO: disable warnings
       - name: CMake
         run: |
           cmake -S . -B cmake.output -DCMAKE_BUILD_TYPE=RelWithDebInfo -DHAVE_RULES=On -DBUILD_TESTS=On -DBUILD_GUI=ON -DWITH_QCHART=ON -DUSE_MATCHCOMPILER=Verify -DANALYZE_UNDEFINED=On -DENABLE_CHECK_INTERNAL=On -DUSE_BOOST=On -DCPPCHK_GLIBCXX_DEBUG=Off -DCMAKE_DISABLE_PRECOMPILE_HEADERS=On -DCMAKE_GLOBAL_AUTOGEN_TARGET=On -DDISABLE_DMAKE=On -DCMAKE_C_COMPILER_LAUNCHER=ccache -DCMAKE_CXX_COMPILER_LAUNCHER=ccache
diff --git a/.github/workflows/valgrind.yml b/.github/workflows/valgrind.yml
index cf03ff89f..97f875d52 100644
--- a/.github/workflows/valgrind.yml
+++ b/.github/workflows/valgrind.yml
@@ -38,12 +38,12 @@ jobs:
       - name: Build cppcheck
         run: |
           export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
-          CXXFLAGS="-O1 -g -DHAVE_BOOST" make -j$(nproc) HAVE_RULES=yes MATCHCOMPILER=yes
+          CXXFLAGS="-O1 -g -w -DHAVE_BOOST" make -j$(nproc) HAVE_RULES=yes MATCHCOMPILER=yes
 
       - name: Build test
         run: |
           export PATH="/usr/lib/ccache:/usr/local/opt/ccache/libexec:$PATH"
-          CXXFLAGS="-O1 -g -DHAVE_BOOST" make -j$(nproc) testrunner HAVE_RULES=yes MATCHCOMPILER=yes
+          CXXFLAGS="-O1 -g -w -DHAVE_BOOST" make -j$(nproc) testrunner HAVE_RULES=yes MATCHCOMPILER=yes
 
       - name: Run valgrind
         run: |
diff --git a/Makefile b/Makefile
index 75a849bbd..f5844225c 100644
--- a/Makefile
+++ b/Makefile
@@ -137,7 +137,7 @@ ifeq (clang++, $(findstring clang++,$(CXX)))
     CPPCHK_GLIBCXX_DEBUG=
 endif
 ifndef CXXFLAGS
-    CXXFLAGS=-pedantic -Wall -Wextra -Wcast-qual -Wno-deprecated-declarations -Wfloat-equal -Wmissing-declarations -Wmissing-format-attribute -Wno-long-long -Wpacked -Wredundant-decls -Wundef -Wno-shadow -Wno-missing-field-initializers -Wno-missing-braces -Wno-sign-compare -Wno-multichar $(CPPCHK_GLIBCXX_DEBUG) -g
+    CXXFLAGS=-pedantic -Wall -Wextra -Wcast-qual -Wfloat-equal -Wmissing-declarations -Wmissing-format-attribute -Wno-long-long -Wpacked -Wredundant-decls -Wundef -Wno-shadow -Wno-missing-field-initializers -Wno-missing-braces -Wno-sign-compare -Wno-multichar -Woverloaded-virtual $(CPPCHK_GLIBCXX_DEBUG) -g
 endif
 
 ifeq (g++, $(findstring g++,$(CXX)))
@@ -575,7 +575,7 @@ $(libcppdir)/ctu.o: lib/ctu.cpp externals/tinyxml2/tinyxml2.h lib/addoninfo.h li
 $(libcppdir)/errorlogger.o: lib/errorlogger.cpp externals/tinyxml2/tinyxml2.h lib/addoninfo.h lib/analyzerinfo.h lib/check.h lib/color.h lib/config.h lib/cppcheck.h lib/errorlogger.h lib/errortypes.h lib/importproject.h lib/library.h lib/mathlib.h lib/path.h lib/platform.h lib/settings.h lib/standards.h lib/suppressions.h lib/templatesimplifier.h lib/token.h lib/tokenlist.h lib/utils.h lib/vfvalue.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/errorlogger.cpp
 
-$(libcppdir)/errortypes.o: lib/errortypes.cpp lib/config.h lib/errortypes.h
+$(libcppdir)/errortypes.o: lib/errortypes.cpp lib/config.h lib/errortypes.h lib/utils.h
 	$(CXX) ${INCLUDE_FOR_LIB} $(CPPFLAGS) $(CXXFLAGS) -c -o $@ $(libcppdir)/errortypes.cpp
 
 $(libcppdir)/forwardanalyzer.o: lib/forwardanalyzer.cpp lib/addoninfo.h lib/analyzer.h lib/astutils.h lib/config.h lib/errortypes.h lib/forwardanalyzer.h lib/importproject.h lib/library.h lib/mathlib.h lib/platform.h lib/settings.h lib/smallvector.h lib/sourcelocation.h lib/standards.h lib/suppressions.h lib/symboldatabase.h lib/templatesimplifier.h lib/token.h lib/utils.h lib/valueptr.h lib/vfvalue.h
diff --git a/cmake/compileroptions.cmake b/cmake/compileroptions.cmake
index 4c5ad9af8..38df5d106 100644
--- a/cmake/compileroptions.cmake
+++ b/cmake/compileroptions.cmake
@@ -43,13 +43,20 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID MATCHES "Clang
     add_compile_options(-Wno-missing-braces)
     add_compile_options(-Wno-sign-compare)
     add_compile_options(-Wno-multichar)
+    add_compile_options(-Woverloaded-virtual)       # when a function declaration hides virtual functions from a base class
+
+    # TODO: evaluate
+    #add_compile_options(-Wconversion)  # danmar: gives fp. for instance: unsigned int sizeof_pointer = sizeof(void *);
+    #add_compile_options(-Wlogical-op) # doesn't work on older GCC
+    #add_compile_options(-Wsign-conversion) # too many warnings
+    #add_compile_options(-Wunreachable-code) # some GCC versions report lots of warnings
+    #add_compile_options(-Wsign-promo)
 endif()
 
 if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     # use pipes instead of temporary files - greatly reduces I/O usage
     add_compile_options(-pipe)
 
-    add_compile_options(-Woverloaded-virtual)       # when a function declaration hides virtual functions from a base class
     add_compile_options(-Wno-maybe-uninitialized)   # there are some false positives
     add_compile_options(-Wsuggest-attribute=noreturn)
     add_compile_options(-Wno-shadow)                # whenever a local variable or type declaration shadows another one
diff --git a/lib/errortypes.cpp b/lib/errortypes.cpp
index cd9ca5771..1653df844 100644
--- a/lib/errortypes.cpp
+++ b/lib/errortypes.cpp
@@ -18,6 +18,8 @@
 
 #include "errortypes.h"
 
+#include "utils.h"
+
 static std::string typeToString(InternalError::Type type)
 {
     switch (type) {
@@ -34,6 +36,7 @@ static std::string typeToString(InternalError::Type type)
     case InternalError::Type::INSTANTIATION:
         return "instantiationError";
     }
+    cppcheck::unreachable();
 }
 
 InternalError::InternalError(const Token *tok, std::string errorMsg, Type type) :
diff --git a/lib/keywords.cpp b/lib/keywords.cpp
index 87f1bef35..192b5faac 100644
--- a/lib/keywords.cpp
+++ b/lib/keywords.cpp
@@ -18,6 +18,8 @@
 
 #include "keywords.h"
 
+#include "utils.h"
+
 #include <cassert>
 
 // see https://en.cppreference.com/w/c/keyword
@@ -164,7 +166,7 @@ const std::unordered_set<std::string>& Keywords::getAll(Standards::cstd_t cStd)
         /*case Standards::cstd_t::C23:
             return c23_keywords_all;*/
     }
-    assert(false && "unreachable");
+    cppcheck::unreachable();
 }
 
 // cppcheck-suppress unusedFunction
@@ -184,7 +186,7 @@ const std::unordered_set<std::string>& Keywords::getAll(Standards::cppstd_t cppS
     case Standards::cppstd_t::CPP23:
         return cpp23_keywords_all;
     }
-    assert(false && "unreachable");
+    cppcheck::unreachable();
 }
 
 // cppcheck-suppress unusedFunction
@@ -201,7 +203,7 @@ const std::unordered_set<std::string>& Keywords::getOnly(Standards::cstd_t cStd)
         /*case Standards::cstd_t::C23:
             return c23_keywords_all;*/
     }
-    assert(false && "unreachable");
+    cppcheck::unreachable();
 }
 
 // cppcheck-suppress unusedFunction
@@ -222,6 +224,6 @@ const std::unordered_set<std::string>& Keywords::getOnly(Standards::cppstd_t cpp
     case Standards::cppstd_t::CPP23:
         return cpp23_keywords;
     }
-    assert(false && "unreachable");
+    cppcheck::unreachable();
 }
 
diff --git a/lib/symboldatabase.cpp b/lib/symboldatabase.cpp
index c6d2cc50a..100603dd3 100644
--- a/lib/symboldatabase.cpp
+++ b/lib/symboldatabase.cpp
@@ -3044,7 +3044,7 @@ bool Function::returnsConst(const Function* function, bool unknown)
 
 bool Function::returnsReference(const Function* function, bool unknown, bool includeRValueRef)
 {
-    return checkReturns(function, unknown, false, [includeRValueRef](UNUSED const Token* defStart, const Token* defEnd) {
+    return checkReturns(function, unknown, false, [includeRValueRef](const Token* /*defStart*/, const Token* defEnd) {
         return includeRValueRef ? Token::Match(defEnd->previous(), "&|&&") : Token::simpleMatch(defEnd->previous(), "&");
     });
 }
diff --git a/lib/utils.h b/lib/utils.h
index 5218ab1c4..2ac0df275 100644
--- a/lib/utils.h
+++ b/lib/utils.h
@@ -331,4 +331,18 @@ static inline const char* bool_to_string(bool b)
     return b ? "true" : "false";
 }
 
+namespace cppcheck
+{
+    NORETURN inline void unreachable()
+    {
+#if defined(__GNUC__)
+        __builtin_unreachable();
+#elif defined(_MSC_VER)
+        __assume(false);
+#else
+#error "no unreachable implementation"
+#endif
+    }
+}
+
 #endif
diff --git a/tools/dmake.cpp b/tools/dmake.cpp
index 0072f211f..c9b47989e 100644
--- a/tools/dmake.cpp
+++ b/tools/dmake.cpp
@@ -589,36 +589,26 @@ int main(int argc, char **argv)
 
     // Makefile settings..
     if (release) {
-        makeConditionalVariable(fout, "CXXFLAGS", "-std=c++0x -O2 -DNDEBUG -Wall -Wno-sign-compare");
+        makeConditionalVariable(fout, "CXXFLAGS", "-std=c++0x -O2 -DNDEBUG -Wall -Wno-sign-compare -Wno-multichar");
     } else {
-        // TODO: add more compiler warnings.
-        // -Wlogical-op       : doesn't work on older GCC
-        // -Wsign-conversion  : too many warnings
-        // -Wunreachable-code : some GCC versions report lots of warnings
         makeConditionalVariable(fout, "CXXFLAGS",
                                 "-pedantic "
                                 "-Wall "
                                 "-Wextra "
                                 "-Wcast-qual "
-//                                "-Wconversion "  // danmar: gives fp. for instance: unsigned int sizeof_pointer = sizeof(void *);
-                                "-Wno-deprecated-declarations "
                                 "-Wfloat-equal "
-//                                "-Wlogical-op "
                                 "-Wmissing-declarations "
                                 "-Wmissing-format-attribute "
                                 "-Wno-long-long "
-//                                "-Woverloaded-virtual "  // danmar: we get fp when overloading analyseWholeProgram()
                                 "-Wpacked "
                                 "-Wredundant-decls "
                                 "-Wundef "
                                 "-Wno-shadow "
-//                                "-Wsign-conversion "
-//                                "-Wsign-promo "
                                 "-Wno-missing-field-initializers "
                                 "-Wno-missing-braces "
-//                                "-Wunreachable-code "
-                                "-Wno-sign-compare "  // danmar: I don't like this warning, it's very rarely a bug
+                                "-Wno-sign-compare "
                                 "-Wno-multichar "
+                                "-Woverloaded-virtual "
                                 "$(CPPCHK_GLIBCXX_DEBUG) "
                                 "-g");
     }