diff --git a/cranelift/codegen/meta/src/cdsl/formats.rs b/cranelift/codegen/meta/src/cdsl/formats.rs
index b716a8a976..a3249b4c6e 100644
--- a/cranelift/codegen/meta/src/cdsl/formats.rs
+++ b/cranelift/codegen/meta/src/cdsl/formats.rs
@@ -89,27 +89,6 @@ pub struct InstructionFormatBuilder {
     typevar_operand: Option<usize>,
 }
 
-pub struct ImmParameter {
-    kind: OperandKind,
-    member: &'static str,
-}
-impl Into<ImmParameter> for (&'static str, &OperandKind) {
-    fn into(self) -> ImmParameter {
-        ImmParameter {
-            kind: self.1.clone(),
-            member: self.0,
-        }
-    }
-}
-impl Into<ImmParameter> for &OperandKind {
-    fn into(self) -> ImmParameter {
-        ImmParameter {
-            kind: self.clone(),
-            member: self.default_member.unwrap(),
-        }
-    }
-}
-
 impl InstructionFormatBuilder {
     pub fn new(name: &'static str) -> Self {
         Self {
@@ -131,12 +110,21 @@ impl InstructionFormatBuilder {
         self
     }
 
-    pub fn imm(mut self, param: impl Into<ImmParameter>) -> Self {
-        let imm_param = param.into();
+    pub fn imm(mut self, operand_kind: &OperandKind) -> Self {
         let field = FormatField {
             immnum: self.imm_fields.len(),
-            kind: imm_param.kind,
-            member: imm_param.member,
+            kind: operand_kind.clone(),
+            member: operand_kind.default_member.unwrap(),
+        };
+        self.imm_fields.push(field);
+        self
+    }
+
+    pub fn imm_with_name(mut self, member: &'static str, operand_kind: &OperandKind) -> Self {
+        let field = FormatField {
+            immnum: self.imm_fields.len(),
+            kind: operand_kind.clone(),
+            member,
         };
         self.imm_fields.push(field);
         self
diff --git a/cranelift/codegen/meta/src/shared/formats.rs b/cranelift/codegen/meta/src/shared/formats.rs
index 394eb6d58f..2a16f250a1 100644
--- a/cranelift/codegen/meta/src/shared/formats.rs
+++ b/cranelift/codegen/meta/src/shared/formats.rs
@@ -60,10 +60,14 @@ pub fn define(immediates: &OperandKinds, entities: &OperandKinds) -> FormatRegis
     registry.insert(
         Builder::new("InsertLane")
             .value()
-            .imm(("lane", uimm8))
+            .imm_with_name("lane", uimm8)
             .value(),
     );
-    registry.insert(Builder::new("ExtractLane").value().imm(("lane", uimm8)));
+    registry.insert(
+        Builder::new("ExtractLane")
+            .value()
+            .imm_with_name("lane", uimm8),
+    );
 
     registry.insert(Builder::new("IntCompare").imm(intcc).value().value());
     registry.insert(Builder::new("IntCompareImm").imm(intcc).value().imm(imm64));
@@ -151,26 +155,26 @@ pub fn define(immediates: &OperandKinds, entities: &OperandKinds) -> FormatRegis
     registry.insert(
         Builder::new("RegMove")
             .value()
-            .imm(("src", regunit))
-            .imm(("dst", regunit)),
+            .imm_with_name("src", regunit)
+            .imm_with_name("dst", regunit),
     );
     registry.insert(
         Builder::new("CopySpecial")
-            .imm(("src", regunit))
-            .imm(("dst", regunit)),
+            .imm_with_name("src", regunit)
+            .imm_with_name("dst", regunit),
     );
-    registry.insert(Builder::new("CopyToSsa").imm(("src", regunit)));
+    registry.insert(Builder::new("CopyToSsa").imm_with_name("src", regunit));
     registry.insert(
         Builder::new("RegSpill")
             .value()
-            .imm(("src", regunit))
-            .imm(("dst", stack_slot)),
+            .imm_with_name("src", regunit)
+            .imm_with_name("dst", stack_slot),
     );
     registry.insert(
         Builder::new("RegFill")
             .value()
-            .imm(("src", stack_slot))
-            .imm(("dst", regunit)),
+            .imm_with_name("src", stack_slot)
+            .imm_with_name("dst", regunit),
     );
 
     registry.insert(Builder::new("Trap").imm(trapcode));