Fix build on windows

.github/workflows/reusable-build-test-config.yml

@@ -295,7 +295,10 @@ jobs:
       - name: Run Rust tests
         if: ${{ !inputs.build_only }}
         working-directory: crates
-        run: cargo nextest run --workspace --all-features --locked --no-tests=warn
+        # `xrpl-wasm-vm-ffi` is left out on Windows: its tests link as an executable, and
+        # MSVC - unlike the Unix linkers - will not dead-strip the never-called cxx wrappers
+        # whose C++ shims only the CMake build defines. The other runners cover these tests.
+        run: cargo nextest run --workspace --all-features --locked --no-tests=warn ${{ runner.os == 'Windows' && '--exclude xrpl-wasm-vm-ffi' || '' }}
 
       - name: Run the separate tests
         if: ${{ !inputs.build_only }}

src/libxrpl/tx/wasm/WasmVM.cpp

@@ -31,7 +31,9 @@ using CheckStatus = rs::wasm_vm::CheckStatus;
 //
 // Exhaustive over the status enum, with no `default`: the enum is generated from the
 // engine's `RunError`, so an outcome added there fails this switch under -Wswitch -Werror
-// rather than quietly picking up a neighbour's TER.
+// rather than quietly picking up a neighbour's TER. The return past the switch is for the
+// compilers that will not call an exhaustive switch exhaustive; it sits after the switch,
+// not in a `default`, so the coverage check above still holds.
 std::expected<EscrowResult, WasmTER>
 outcome(rs::wasm_vm::RunResult const& run)
 {
@@ -73,7 +75,8 @@ outcome(rs::wasm_vm::RunResult const& run)
         case RunStatus::Panic:
             return std::unexpected{WasmTER{.ter = tecINTERNAL, .cost = std::nullopt}};
     }
-    UNREACHABLE("Unexpected RunStatus value");
+    UNREACHABLE("xrpl::outcome : unknown RunStatus");
+    return std::unexpected{WasmTER{.ter = tecINTERNAL, .cost = std::nullopt}};
 }
 
 // A screening verdict as a TER.
@@ -106,7 +109,8 @@ verdict(CheckStatus status)
         case CheckStatus::Panic:
             return telFAILED_PROCESSING;
     }
-    UNREACHABLE("Unexpected CheckStatus value");
+    UNREACHABLE("xrpl::verdict : unknown CheckStatus");
+    return telFAILED_PROCESSING;
 }
 
 }  // namespace