diff --git a/autogen/src/dr.rs b/autogen/src/dr.rs
index e548ca92..c929ed9e 100644
--- a/autogen/src/dr.rs
+++ b/autogen/src/dr.rs
@@ -1,3 +1,5 @@
+use std::collections::HashSet;
+
 use crate::structs;
 use crate::utils::*;
 
@@ -240,7 +242,19 @@ pub fn gen_dr_operand_kinds(grammar: &[structs::OperandKind]) -> TokenStream {
     };
 
     let kind_enum = {
-        let kinds = kind_and_ty.iter().map(|(kind, ty)| quote! {#kind(#ty)});
+        let mut types_seen = HashSet::new();
+
+        // To prevent ambiguity we don't want to generate an implementation for `Word` at all:
+        types_seen.insert(quote!(spirv::Word).to_string());
+
+        let kinds = kind_and_ty.iter().map(|(kind, ty)| {
+            let v = quote!(#kind(#ty));
+            if types_seen.insert(ty.to_string()) {
+                v
+            } else {
+                quote!(#[from(ignore)] #v)
+            }
+        });
         quote! {
             #[doc = "Data representation of a SPIR-V operand."]
             #[derive(Clone, Debug, PartialEq, From)]
diff --git a/autogen/src/sr.rs b/autogen/src/sr.rs
index 6bfe12fe..14f935aa 100644
--- a/autogen/src/sr.rs
+++ b/autogen/src/sr.rs
@@ -235,11 +235,10 @@ pub fn gen_sr_code_from_operand_kind_grammar(
         })
         .collect();
     let tokens = quote! {
-        use derive_more::From;
         use spirv;
 
         /// SPIR-V decorations.
-        #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, From)]
+        #[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
         pub enum Decoration {
             #( #enumerants ),*
         }
diff --git a/rspirv/dr/autogen_operand.rs b/rspirv/dr/autogen_operand.rs
index 02bcbc54..05549ff3 100644
--- a/rspirv/dr/autogen_operand.rs
+++ b/rspirv/dr/autogen_operand.rs
@@ -40,13 +40,17 @@ pub enum Operand {
     RayQueryIntersection(spirv::RayQueryIntersection),
     RayQueryCommittedIntersectionType(spirv::RayQueryCommittedIntersectionType),
     RayQueryCandidateIntersectionType(spirv::RayQueryCandidateIntersectionType),
+    #[from(ignore)]
     IdMemorySemantics(spirv::Word),
+    #[from(ignore)]
     IdScope(spirv::Word),
+    #[from(ignore)]
     IdRef(spirv::Word),
     LiteralInt32(u32),
     LiteralInt64(u64),
     LiteralFloat32(f32),
     LiteralFloat64(f64),
+    #[from(ignore)]
     LiteralExtInstInteger(u32),
     LiteralSpecConstantOpInteger(spirv::Op),
     LiteralString(String),
diff --git a/rspirv/sr/autogen_decoration.rs b/rspirv/sr/autogen_decoration.rs
index ace64096..2c35bd90 100644
--- a/rspirv/sr/autogen_decoration.rs
+++ b/rspirv/sr/autogen_decoration.rs
@@ -2,10 +2,9 @@
 //   external/spirv.core.grammar.json.
 // DO NOT MODIFY!
 
-use derive_more::From;
 use spirv;
 #[doc = r" SPIR-V decorations."]
-#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord, From)]
+#[derive(Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub enum Decoration {
     RelaxedPrecision,
     SpecId(u32),