diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 73da07d885..526514c60a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -25,7 +25,7 @@ jobs:
   build_linux:
     strategy:
       matrix:
-        compiler: [gcc, clang-16]
+        compiler: [ {c: gcc, cpp: g++}, {c: clang-16, cpp: clang++-16} ]
     runs-on: ubuntu-22.04
     timeout-minutes: 32
 
@@ -40,7 +40,8 @@ jobs:
         uses: devcontainers/ci@v0.2
         with:
           runCmd: |
-            export CC=${{ matrix.compiler }}
+            export  CC=${{ matrix.compiler.c }}
+            export CXX=${{ matrix.compiler.cpp }}
 
             export TOOLCHAIN=$(pwd)/cmake/lld.toolchain.cmake
 
diff --git a/include/vast/Util/Warnings.hpp b/include/vast/Util/Warnings.hpp
index 543d604b6d..cb40b0845c 100644
--- a/include/vast/Util/Warnings.hpp
+++ b/include/vast/Util/Warnings.hpp
@@ -21,7 +21,8 @@
 #define VAST_GCC_RELAX_WARNINGS \
   _Pragma( "GCC diagnostic ignored \"-Wuseless-cast\"" ) \
   _Pragma( "GCC diagnostic ignored \"-Wnull-dereference\"" ) \
-  _Pragma( "GCC diagnostic ignored \"-Wmaybe-uninitialized\"" )
+  _Pragma( "GCC diagnostic ignored \"-Wmaybe-uninitialized\"" ) \
+  _Pragma( "GCC diagnostic ignored \"-Wduplicated-branches\"" )
 
 #ifdef __clang__
 #define VAST_RELAX_WARNINGS \
diff --git a/include/vast/repl/command.hpp b/include/vast/repl/command.hpp
index fe0798e966..59511240d3 100644
--- a/include/vast/repl/command.hpp
+++ b/include/vast/repl/command.hpp
@@ -114,7 +114,7 @@ namespace vast::repl
             } else {
                 using current = typename std::tuple_element< 0, params_storage >::type;
 
-                if constexpr (current::param_name == name) {
+                if constexpr (std::string_view(current::param_name) == name) {
                     return util::head(params).value;
                 } else {
                     return get_param< name >(util::tail(params));
diff --git a/lib/vast/Dialect/HighLevel/HighLevelLinkage.cpp b/lib/vast/Dialect/HighLevel/HighLevelLinkage.cpp
index 20b63d7320..38e8881755 100644
--- a/lib/vast/Dialect/HighLevel/HighLevelLinkage.cpp
+++ b/lib/vast/Dialect/HighLevel/HighLevelLinkage.cpp
@@ -250,7 +250,7 @@ namespace vast::hl {
         auto &actx = decl->getASTContext();
         auto linkage = actx.GetGVALinkageForFunction(decl);
 
-        if (const auto *dtor = clang::dyn_cast< clang::CXXDestructorDecl >(decl)) {
+        if (/*const auto *dtor =*/ clang::dyn_cast< clang::CXXDestructorDecl >(decl)) {
             VAST_UNIMPLEMENTED;
         }
 
diff --git a/lib/vast/Frontend/GenAction.cpp b/lib/vast/Frontend/GenAction.cpp
index 668e6ea757..a8b963d61b 100644
--- a/lib/vast/Frontend/GenAction.cpp
+++ b/lib/vast/Frontend/GenAction.cpp
@@ -183,6 +183,7 @@ namespace vast::cc {
                 case target_dialect::low_level: return "low_level";
                 case target_dialect::llvm: return "llvm";
             }
+            VAST_UNREACHABLE("Unknown target dialect to string.");
         }
 
         void compile_via_vast(auto mod, mcontext_t *mctx)
diff --git a/lib/vast/Translation/CodeGenDriver.cpp b/lib/vast/Translation/CodeGenDriver.cpp
index 325c8d5b08..c912d3230d 100644
--- a/lib/vast/Translation/CodeGenDriver.cpp
+++ b/lib/vast/Translation/CodeGenDriver.cpp
@@ -236,7 +236,7 @@ namespace vast::cg
                 VAST_UNIMPLEMENTED_MSG("codegen for multi version function");
             }
 
-            if (const auto *method = llvm::dyn_cast< clang::CXXMethodDecl >(decl)) {
+            if (/*const auto *method =*/ llvm::dyn_cast< clang::CXXMethodDecl >(decl)) {
                 VAST_UNIMPLEMENTED_MSG("cxx methods");
             }
 
diff --git a/lib/vast/Translation/CodeGenFunction.cpp b/lib/vast/Translation/CodeGenFunction.cpp
index 6532258266..982c677d34 100644
--- a/lib/vast/Translation/CodeGenFunction.cpp
+++ b/lib/vast/Translation/CodeGenFunction.cpp
@@ -74,7 +74,7 @@ namespace vast::cg
     bool codegen_driver::may_drop_function_return(qual_type rty) const {
         // We can't just disard the return value for a record type with a complex
         // destructor or a non-trivially copyable type.
-        if (const auto *recorrd_type = rty.getCanonicalType()->getAs< clang::RecordType >()) {
+        if (/*const auto *record_type =*/ rty.getCanonicalType()->getAs< clang::RecordType >()) {
             VAST_UNIMPLEMENTED;
         }
 
diff --git a/lib/vast/Translation/CodeGenStmtVisitor.cpp b/lib/vast/Translation/CodeGenStmtVisitor.cpp
index 73603e48e8..c34350cdf9 100644
--- a/lib/vast/Translation/CodeGenStmtVisitor.cpp
+++ b/lib/vast/Translation/CodeGenStmtVisitor.cpp
@@ -104,6 +104,7 @@ namespace vast::hl
             case clang::PredefinedExpr::IdentKind::PrettyFunctionNoVirtual :
                 return IdentKind::PrettyFunctionNoVirtual;
         }
+        VAST_UNREACHABLE( "unsupported ident kind" );
     }
 
 } // namespace vast::hl
diff --git a/lib/vast/Translation/Mangler.cpp b/lib/vast/Translation/Mangler.cpp
index fa6d66e5dc..398f869fd1 100644
--- a/lib/vast/Translation/Mangler.cpp
+++ b/lib/vast/Translation/Mangler.cpp
@@ -11,7 +11,7 @@ namespace vast::cg
 
         // Some ABIs don't have constructor variants. Make sure that base and complete
         // constructors get mangled the same.
-        if (const auto *ctor = clang::dyn_cast< clang::CXXConstructorDecl >(canonical.getDecl())) {
+        if (/*const auto *ctor =*/ clang::dyn_cast< clang::CXXConstructorDecl >(canonical.getDecl())) {
             VAST_UNIMPLEMENTED_IF(!target_info.getCXXABI().hasConstructorVariants());
         }
 
diff --git a/tools/vast-repl/vast-repl.cpp b/tools/vast-repl/vast-repl.cpp
index 727e3d705b..9be90c2252 100644
--- a/tools/vast-repl/vast-repl.cpp
+++ b/tools/vast-repl/vast-repl.cpp
@@ -57,7 +57,7 @@ namespace vast::repl
 
             while (!cli.exit()) {
                 std::string cmd;
-                if (auto quit = linenoise::Readline("> ", cmd)) {
+                if (linenoise::Readline("> ", cmd)) {
                     break;
                 }