diff --git a/src/intrinsics/llvm.rs b/src/intrinsics/llvm.rs
index 20f8699d12a..5bbbc18b3f4 100644
--- a/src/intrinsics/llvm.rs
+++ b/src/intrinsics/llvm.rs
@@ -8,14 +8,14 @@ use rustc_middle::ty::subst::SubstsRef;
 pub(crate) fn codegen_llvm_intrinsic_call<'tcx>(
     fx: &mut FunctionCx<'_, '_, 'tcx>,
     intrinsic: &str,
-    substs: SubstsRef<'tcx>,
+    _substs: SubstsRef<'tcx>,
     args: &[mir::Operand<'tcx>],
     destination: Option<(CPlace<'tcx>, BasicBlock)>,
 ) {
     let ret = destination.unwrap().0;
 
     intrinsic_match! {
-        fx, intrinsic, substs, args,
+        fx, intrinsic, args,
         _ => {
             fx.tcx.sess.warn(&format!("unsupported llvm intrinsic {}; replacing with trap", intrinsic));
             crate::trap::trap_unimplemented(fx, intrinsic);
diff --git a/src/intrinsics/mod.rs b/src/intrinsics/mod.rs
index 693b0e21444..825b317d131 100644
--- a/src/intrinsics/mod.rs
+++ b/src/intrinsics/mod.rs
@@ -43,28 +43,21 @@ macro intrinsic_arg {
 }
 
 macro intrinsic_match {
-    ($fx:expr, $intrinsic:expr, $substs:expr, $args:expr,
+    ($fx:expr, $intrinsic:expr, $args:expr,
     _ => $unknown:block;
     $(
         $($($name:tt).*)|+ $(if $cond:expr)?, ($($a:ident $arg:ident),*) $content:block;
     )*) => {
-        let _ = $substs; // Silence warning when substs is unused.
         match $intrinsic {
             $(
                 $(intrinsic_pat!($($name).*))|* $(if $cond)? => {
-                    #[allow(unused_parens, non_snake_case)]
-                    {
-                        if let [$($arg),*] = $args {
-                            let ($($arg,)*) = (
-                                $(intrinsic_arg!($a $fx, $arg),)*
-                            );
-                            #[warn(unused_parens, non_snake_case)]
-                            {
-                                $content
-                            }
-                        } else {
-                            bug!("wrong number of args for intrinsic {:?}", $intrinsic);
-                        }
+                    if let [$($arg),*] = $args {
+                        let ($($arg,)*) = (
+                            $(intrinsic_arg!($a $fx, $arg),)*
+                        );
+                        $content
+                    } else {
+                        bug!("wrong number of args for intrinsic {:?}", $intrinsic);
                     }
                 }
             )*
@@ -357,7 +350,7 @@ fn codegen_regular_intrinsic_call<'tcx>(
     let usize_layout = fx.layout_of(fx.tcx.types.usize);
 
     intrinsic_match! {
-        fx, intrinsic, substs, args,
+        fx, intrinsic, args,
         _ => {
             fx.tcx.sess.span_fatal(span, &format!("unsupported intrinsic {}", intrinsic));
         };
diff --git a/src/intrinsics/simd.rs b/src/intrinsics/simd.rs
index 106a190096d..292d3ca45f1 100644
--- a/src/intrinsics/simd.rs
+++ b/src/intrinsics/simd.rs
@@ -68,13 +68,13 @@ macro simd_flt_binop($fx:expr, $op:ident($x:ident, $y:ident) -> $ret:ident) {
 pub(super) fn codegen_simd_intrinsic_call<'tcx>(
     fx: &mut FunctionCx<'_, '_, 'tcx>,
     intrinsic: Symbol,
-    substs: SubstsRef<'tcx>,
+    _substs: SubstsRef<'tcx>,
     args: &[mir::Operand<'tcx>],
     ret: CPlace<'tcx>,
     span: Span,
 ) {
     intrinsic_match! {
-        fx, intrinsic, substs, args,
+        fx, intrinsic, args,
         _ => {
             fx.tcx.sess.span_fatal(span, &format!("Unknown SIMD intrinsic {}", intrinsic));
         };