diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 50548bef..4c3601e4 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -95,8 +95,6 @@ jobs:
   code-coverage:
     name: Collect code coverage
     runs-on: ubuntu-latest
-    # Temporarily disabled due to clang miscompilation?
-    if: false
     steps:
       - uses: actions/checkout@v2
       - name: Install Rust
@@ -109,7 +107,10 @@ jobs:
 
       - name: Install LLVM
         run: |
-          sudo apt-get install -y llvm
+          wget https://apt.llvm.org/llvm.sh
+          chmod +x llvm.sh
+          sudo ./llvm.sh 18
+          sudo apt-get install -y llvm-18 llvm-18-dev clang-tools-18
 
       - name: Install Tree-sitter (with runtime)
         run: |
@@ -125,7 +126,7 @@ jobs:
 
       - name: Build dist-check with coverage
         timeout-minutes: 10
-        run: make coverage -j8
+        run: CC=clang-18 LLVM_SUFFIX=-18 make coverage -j8
 
       - name: Upload coverage reports to Codecov
         uses: codecov/codecov-action@v3
diff --git a/Makefile b/Makefile
index 5602e814..650a0ff3 100644
--- a/Makefile
+++ b/Makefile
@@ -17,7 +17,7 @@ else ifdef FAST_DEBUG
 	CFLAGS += -g0
 	ALUMINA_FLAGS += --debug
 else ifdef COVERAGE
-	CC = clang
+	CC ?= clang
 	BUILD_DIR = $(BUILD_ROOT)/coverage
 	CARGO_FLAGS += --profile coverage
 	CARGO_TARGET_DIR = target/coverage
@@ -326,18 +326,18 @@ coverage:
 	COVERAGE=1 CACHE_AST=1 $(MAKE) all-tests-with-coverage
 
 all-tests-with-coverage: test test-docs test-libraries test-diag examples
-	llvm-profdata merge \
+	llvm-profdata$(LLVM_SUFFIX) merge \
 		-sparse  \
 		$(BUILD_DIR)/profiles/* \
 		-o $(BUILD_DIR)/profiles/merged.profdata
 
-	llvm-cov export \
+	llvm-cov$(LLVM_SUFFIX) export \
 		-Xdemangler=rustfilt \
 		-format=lcov \
 		-instr-profile=$(BUILD_DIR)/profiles/merged.profdata $(ALUMINA_BOOT) \
 		$(BOOTSTRAP_SOURCES) > $(BUILD_DIR)/coverage.txt
 
-	llvm-cov show \
+	llvm-cov$(LLVM_SUFFIX) show \
 		-Xdemangler=rustfilt \
 		-format=html \
 		-instr-profile=$(BUILD_DIR)/profiles/merged.profdata $(ALUMINA_BOOT) \
diff --git a/src/alumina-boot-macros/src/lib.rs b/src/alumina-boot-macros/src/lib.rs
index 90b222ea..0306d04b 100644
--- a/src/alumina-boot-macros/src/lib.rs
+++ b/src/alumina-boot-macros/src/lib.rs
@@ -96,8 +96,8 @@ pub fn ast_serializable(input: TokenStream) -> TokenStream {
                         }
                     });
 
-                let deserialize_fields = variant.fields.iter().enumerate()
-                    .map(|(_i, f)| {
+                let deserialize_fields = variant.fields.iter()
+                    .map(|f| {
                         let ty = &f.ty;
                         quote! {
                             <#ty as #module_path::AstSerializable<#lifetime>>::deserialize(deserializer)?
@@ -167,8 +167,8 @@ pub fn ast_serializable(input: TokenStream) -> TokenStream {
                     }
                 });
 
-            let deserialize_fields = r#struct.fields.iter().enumerate()
-                .map(|(_i, f)| {
+            let deserialize_fields = r#struct.fields.iter()
+                .map(|f| {
                     let ty = &f.ty;
                     if let Some(field) = &f.ident {
                         quote! {
diff --git a/src/alumina-boot/src/ast/serialization.rs b/src/alumina-boot/src/ast/serialization.rs
index 5b892f3b..a4559c7f 100644
--- a/src/alumina-boot/src/ast/serialization.rs
+++ b/src/alumina-boot/src/ast/serialization.rs
@@ -467,6 +467,7 @@ impl<'ast> DeserializeContext<'ast> {
 }
 
 pub struct AstDeserializer<'ast, R: std::io::Read> {
+    #[allow(dead_code)]
     pub global_ctx: GlobalCtx,
     pub ast: &'ast AstCtx<'ast>,
     context: DeserializeContext<'ast>,
diff --git a/src/alumina-boot/src/ir/mod.rs b/src/alumina-boot/src/ir/mod.rs
index ef205f98..c1318300 100644
--- a/src/alumina-boot/src/ir/mod.rs
+++ b/src/alumina-boot/src/ir/mod.rs
@@ -279,6 +279,7 @@ pub struct StructLike<'ir> {
     pub attributes: &'ir [Attribute<'ir>],
     pub fields: &'ir [Field<'ir>],
     pub is_union: bool,
+    #[allow(dead_code)]
     pub span: Option<Span>,
 }
 
@@ -321,6 +322,7 @@ pub struct Closure<'ir> {
 pub struct Protocol<'ir> {
     pub name: Option<&'ir str>,
     pub methods: &'ir [ProtocolFunction<'ir>],
+    #[allow(dead_code)]
     pub span: Option<Span>,
 }
 
@@ -348,6 +350,7 @@ pub struct Enum<'ir> {
     pub name: Option<&'ir str>,
     pub underlying_type: TyP<'ir>,
     pub members: &'ir [EnumMember<'ir>],
+    #[allow(dead_code)]
     pub span: Option<Span>,
 }