diff --git a/Cargo.lock b/Cargo.lock
index a5e5c0d5..34cc5928 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,14 +1,5 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-[[package]]
-name = "aho-corasick"
-version = "0.7.15"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7404febffaa47dac81aa44dba71523c9d069b1bdc50a77db41195149e17f68e5"
-dependencies = [
- "memchr",
-]
-
 [[package]]
 name = "ansi_term"
 version = "0.11.0"
@@ -78,15 +69,9 @@ dependencies = [
 
 [[package]]
 name = "byteorder"
-version = "1.3.4"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08c48aae112d48ed9f069b33538ea9e3e90aa263cfa3d1c24309612b1f7472de"
-
-[[package]]
-name = "cfg-if"
-version = "0.1.10"
+version = "1.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+checksum = "ae44d1a3d5a19df61dd0c8beb138458ac2a53a7ac09eba97d55592540004306b"
 
 [[package]]
 name = "cfg-if"
@@ -131,22 +116,19 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "02d96d1e189ef58269ebe5b97953da3274d83a93af647c2ddd6f9dab28cedb8d"
 dependencies = [
  "autocfg",
- "cfg-if 1.0.0",
+ "cfg-if",
  "lazy_static",
 ]
 
 [[package]]
 name = "derive_more"
-version = "0.15.0"
+version = "0.99.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7a141330240c921ec6d074a3e188a7c7ef95668bb95e7d44fa0e5778ec2a7afe"
+checksum = "41cb0e6161ad61ed084a36ba71fbba9e3ac5aee3606fb607fe08da6acbcf3d8c"
 dependencies = [
- "lazy_static",
- "proc-macro2 0.4.30",
- "quote 0.6.13",
- "regex",
- "rustc_version",
- "syn 0.15.44",
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
@@ -171,20 +153,20 @@ dependencies = [
 
 [[package]]
 name = "getrandom"
-version = "0.1.15"
+version = "0.1.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc587bc0ec293155d5bfa6b9891ec18a1e330c234f896ea47fbada4cadbe47e6"
+checksum = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
 dependencies = [
- "cfg-if 0.1.10",
+ "cfg-if",
  "libc",
  "wasi",
 ]
 
 [[package]]
 name = "heck"
-version = "0.3.1"
+version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
+checksum = "87cbf45460356b7deeb5e3415b5563308c0a9b057c85e12b06ad551f98d0a6ac"
 dependencies = [
  "unicode-segmentation",
 ]
@@ -200,9 +182,9 @@ dependencies = [
 
 [[package]]
 name = "itoa"
-version = "0.4.6"
+version = "0.4.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dc6f3ad7b9d11a0c00842ff8de1b60ee58661048eb8049ed33c73594f359d7e6"
+checksum = "dd25036021b0de88a0aff6b850051563c6516d0bf53f8638938edbb9de732736"
 
 [[package]]
 name = "lazy_static"
@@ -212,15 +194,9 @@ checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
 
 [[package]]
 name = "libc"
-version = "0.2.81"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
-
-[[package]]
-name = "memchr"
-version = "2.3.4"
+version = "0.2.82"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ee1c47aaa256ecabcaea351eae4a9b01ef39ed810004e298d2511ed284b1525"
+checksum = "89203f3fba0a3795506acaad8ebce3c80c0af93f994d5a1d7a0b1eeb23271929"
 
 [[package]]
 name = "num-traits"
@@ -231,40 +207,22 @@ dependencies = [
  "autocfg",
 ]
 
-[[package]]
-name = "proc-macro2"
-version = "0.4.30"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "cf3d2011ab5c909338f7887f4fc896d35932e29146c12c8d01da6b22a80ba759"
-dependencies = [
- "unicode-xid 0.1.0",
-]
-
 [[package]]
 name = "proc-macro2"
 version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e0704ee1a7e00d7bb417d0770ea303c1bccbabf0ef1667dae92b5967f5f8a71"
 dependencies = [
- "unicode-xid 0.2.1",
-]
-
-[[package]]
-name = "quote"
-version = "0.6.13"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6ce23b6b870e8f94f81fb0a363d65d86675884b34a09043c81e5562f11c1f8e1"
-dependencies = [
- "proc-macro2 0.4.30",
+ "unicode-xid",
 ]
 
 [[package]]
 name = "quote"
-version = "1.0.7"
+version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "aa563d17ecb180e500da1cfd2b028310ac758de548efdd203e18f283af693f37"
+checksum = "991431c3519a3f36861882da93630ce66b52918dcf1b8e2fd66b397fc96f28df"
 dependencies = [
- "proc-macro2 1.0.24",
+ "proc-macro2",
 ]
 
 [[package]]
@@ -284,24 +242,6 @@ dependencies = [
  "rust-argon2",
 ]
 
-[[package]]
-name = "regex"
-version = "1.4.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "38cf2c13ed4745de91a5eb834e11c00bcc3709e773173b2ce4c56c9fbde04b9c"
-dependencies = [
- "aho-corasick",
- "memchr",
- "regex-syntax",
- "thread_local",
-]
-
-[[package]]
-name = "regex-syntax"
-version = "0.6.21"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3b181ba2dcf07aaccad5448e8ead58db5b742cf85dfe035e2227f137a539a189"
-
 [[package]]
 name = "rspirv"
 version = "0.7.0"
@@ -319,8 +259,8 @@ name = "rspirv-autogen"
 version = "0.1.0"
 dependencies = [
  "heck",
- "proc-macro2 1.0.24",
- "quote 1.0.7",
+ "proc-macro2",
+ "quote",
  "serde",
  "serde_derive",
  "serde_json",
@@ -346,61 +286,37 @@ dependencies = [
  "crossbeam-utils",
 ]
 
-[[package]]
-name = "rustc_version"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
-dependencies = [
- "semver",
-]
-
 [[package]]
 name = "ryu"
 version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
 
-[[package]]
-name = "semver"
-version = "0.9.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1d7eb9ef2c18661902cc47e535f9bc51b78acd254da71d375c2f6720d9a40403"
-dependencies = [
- "semver-parser",
-]
-
-[[package]]
-name = "semver-parser"
-version = "0.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
-
 [[package]]
 name = "serde"
-version = "1.0.118"
+version = "1.0.119"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "06c64263859d87aa2eb554587e2d23183398d617427327cf2b3d0ed8c69e4800"
+checksum = "9bdd36f49e35b61d49efd8aa7fc068fd295961fd2286d0b2ee9a4c7a14e99cc3"
 dependencies = [
  "serde_derive",
 ]
 
 [[package]]
 name = "serde_derive"
-version = "1.0.118"
+version = "1.0.119"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c84d3526699cd55261af4b941e4e725444df67aa4f9e6a3564f18030d12672df"
+checksum = "552954ce79a059ddd5fd68c271592374bd15cab2274970380c000118aeffe1cd"
 dependencies = [
- "proc-macro2 1.0.24",
- "quote 1.0.7",
- "syn 1.0.54",
+ "proc-macro2",
+ "quote",
+ "syn",
 ]
 
 [[package]]
 name = "serde_json"
-version = "1.0.60"
+version = "1.0.61"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1500e84d27fe482ed1dc791a56eddc2f230046a040fa908c08bda1d9fb615779"
+checksum = "4fceb2595057b6891a4ee808f70054bd2d12f0e97f1cbb78689b59f676df325a"
 dependencies = [
  "itoa",
  "ryu",
@@ -424,24 +340,13 @@ checksum = "8ea5119cdb4c55b55d432abb513a0429384878c15dde60cc77b1c99de1a95a6a"
 
 [[package]]
 name = "syn"
-version = "0.15.44"
+version = "1.0.58"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9ca4b3b69a77cbe1ffc9e198781b7acb0c7365a883670e8f1c1bc66fba79a5c5"
+checksum = "cc60a3d73ea6594cd712d830cc1f0390fd71542d8c8cd24e70cc54cdfd5e05d5"
 dependencies = [
- "proc-macro2 0.4.30",
- "quote 0.6.13",
- "unicode-xid 0.1.0",
-]
-
-[[package]]
-name = "syn"
-version = "1.0.54"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9a2af957a63d6bd42255c359c93d9bfdb97076bd3b820897ce55ffbfbf107f44"
-dependencies = [
- "proc-macro2 1.0.24",
- "quote 1.0.7",
- "unicode-xid 0.2.1",
+ "proc-macro2",
+ "quote",
+ "unicode-xid",
 ]
 
 [[package]]
@@ -464,15 +369,6 @@ dependencies = [
  "unicode-width",
 ]
 
-[[package]]
-name = "thread_local"
-version = "1.0.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d40c6d1b69745a6ec6fb1ca717914848da4b44ae29d9b3080cbee91d72a69b14"
-dependencies = [
- "lazy_static",
-]
-
 [[package]]
 name = "unicode-segmentation"
 version = "1.7.1"
@@ -485,12 +381,6 @@ version = "0.1.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9337591893a19b88d8d87f2cec1e73fad5cdfd10e5a6f349f498ad6ea2ffb1e3"
 
-[[package]]
-name = "unicode-xid"
-version = "0.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fc72304796d0818e357ead4e000d19c9c174ab23dc11093ac919054d20a6a7fc"
-
 [[package]]
 name = "unicode-xid"
 version = "0.2.1"
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/Cargo.toml b/rspirv/Cargo.toml
index 93714eea..58184352 100644
--- a/rspirv/Cargo.toml
+++ b/rspirv/Cargo.toml
@@ -19,7 +19,7 @@ travis-ci = { repository = "gfx-rs/rspirv" }
 
 [dependencies]
 clippy = { version = "0.0", optional = true }
-derive_more = "0.15"
+derive_more = "0.99"
 fxhash = "0.2"
 num-traits = "0.2"
 
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/dr/constructs.rs b/rspirv/dr/constructs.rs
index e2112cb6..b1464df1 100644
--- a/rspirv/dr/constructs.rs
+++ b/rspirv/dr/constructs.rs
@@ -309,13 +309,6 @@ impl<'a> convert::From<&'a str> for Operand {
     }
 }
 
-impl convert::From<u32> for Operand {
-    /// Converts the given `u32` `val` into an `Operand::LiteralInt32`.
-    fn from(val: u32) -> Self {
-        Operand::LiteralInt32(val)
-    }
-}
-
 #[cfg(test)]
 mod tests {
     use crate::dr;
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),
diff --git a/spirv/lib.rs b/spirv/lib.rs
index fc91afe4..e48e2b88 100644
--- a/spirv/lib.rs
+++ b/spirv/lib.rs
@@ -12,6 +12,5 @@
 #![cfg_attr(rustfmt, rustfmt_skip)]
 
 use bitflags::bitflags;
-use num_traits;
 
 include!("autogen_spirv.rs");