diff --git a/Cargo.lock b/Cargo.lock
index 9c98946c9d390..a87921056331d 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4262,7 +4262,6 @@ dependencies = [
  "rustc_error_messages",
  "rustc_errors",
  "rustc_feature",
- "rustc_fluent_macro",
  "rustc_graphviz",
  "rustc_hashes",
  "rustc_hir",
diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs
index 02298dbf82670..d15121614693a 100644
--- a/compiler/rustc_driver_impl/src/lib.rs
+++ b/compiler/rustc_driver_impl/src/lib.rs
@@ -121,7 +121,6 @@ pub static DEFAULT_LOCALE_RESOURCES: &[&str] = &[
     rustc_errors::DEFAULT_LOCALE_RESOURCE,
     rustc_hir_analysis::DEFAULT_LOCALE_RESOURCE,
     rustc_lint::DEFAULT_LOCALE_RESOURCE,
-    rustc_middle::DEFAULT_LOCALE_RESOURCE,
     rustc_mir_build::DEFAULT_LOCALE_RESOURCE,
     rustc_parse::DEFAULT_LOCALE_RESOURCE,
     rustc_passes::DEFAULT_LOCALE_RESOURCE,
diff --git a/compiler/rustc_middle/Cargo.toml b/compiler/rustc_middle/Cargo.toml
index fbcce16cedca8..f9d5e7c027894 100644
--- a/compiler/rustc_middle/Cargo.toml
+++ b/compiler/rustc_middle/Cargo.toml
@@ -18,7 +18,6 @@ rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_error_messages = { path = "../rustc_error_messages" } # Used for intra-doc links
 rustc_errors = { path = "../rustc_errors" }
 rustc_feature = { path = "../rustc_feature" }
-rustc_fluent_macro = { path = "../rustc_fluent_macro" }
 rustc_graphviz = { path = "../rustc_graphviz" }
 rustc_hashes = { path = "../rustc_hashes" }
 rustc_hir = { path = "../rustc_hir" }
diff --git a/compiler/rustc_middle/messages.ftl b/compiler/rustc_middle/messages.ftl
deleted file mode 100644
index b46f43841c8e8..0000000000000
--- a/compiler/rustc_middle/messages.ftl
+++ /dev/null
@@ -1,133 +0,0 @@
-middle_assert_async_resume_after_drop = `async fn` resumed after async drop
-
-middle_assert_async_resume_after_panic = `async fn` resumed after panicking
-
-middle_assert_async_resume_after_return = `async fn` resumed after completion
-
-middle_assert_coroutine_resume_after_drop = coroutine resumed after async drop
-
-middle_assert_coroutine_resume_after_panic = coroutine resumed after panicking
-
-middle_assert_coroutine_resume_after_return = coroutine resumed after completion
-
-middle_assert_divide_by_zero =
-    attempt to divide `{$val}` by zero
-
-middle_assert_gen_resume_after_drop = `gen` fn or block cannot be further iterated on after it async dropped
-
-middle_assert_gen_resume_after_panic = `gen` fn or block cannot be further iterated on after it panicked
-
-middle_assert_invalid_enum_construction =
-    trying to construct an enum from an invalid value `{$source}`
-
-middle_assert_misaligned_ptr_deref =
-    misaligned pointer dereference: address must be a multiple of {$required} but is {$found}
-
-middle_assert_null_ptr_deref =
-    null pointer dereference occurred
-
-middle_assert_op_overflow =
-    attempt to compute `{$left} {$op} {$right}`, which would overflow
-
-middle_assert_overflow_neg =
-    attempt to negate `{$val}`, which would overflow
-
-middle_assert_remainder_by_zero =
-    attempt to calculate the remainder of `{$val}` with a divisor of zero
-
-middle_assert_shl_overflow =
-    attempt to shift left by `{$val}`, which would overflow
-
-middle_assert_shr_overflow =
-    attempt to shift right by `{$val}`, which would overflow
-
-middle_autodiff_unsafe_inner_const_ref = reading from a `Duplicated` const {$ty} is unsafe
-
-middle_bounds_check =
-    index out of bounds: the length is {$len} but the index is {$index}
-
-middle_conflict_types =
-    this expression supplies two conflicting concrete types for the same opaque type
-
-middle_consider_type_length_limit =
-    consider adding a `#![type_length_limit="{$type_length}"]` attribute to your crate
-
-middle_const_eval_non_int =
-    constant evaluation of enum discriminant resulted in non-integer
-
-middle_const_not_used_in_type_alias =
-    const parameter `{$ct}` is part of concrete type but not used in parameter list for the `impl Trait` type alias
-
-middle_deprecated = use of deprecated {$kind} `{$path}`{$has_note ->
-        [true] : {$note}
-        *[other] {""}
-    }
-middle_deprecated_in_future = use of {$kind} `{$path}` that will be deprecated in a future Rust version{$has_note ->
-        [true] : {$note}
-        *[other] {""}
-    }
-middle_deprecated_in_version = use of {$kind} `{$path}` that will be deprecated in future version {$version}{$has_note ->
-        [true] : {$note}
-        *[other] {""}
-    }
-middle_deprecated_suggestion = replace the use of the deprecated {$kind}
-
-middle_drop_check_overflow =
-    overflow while adding drop-check rules for `{$ty}`
-    .note = overflowed on `{$overflow_ty}`
-
-middle_erroneous_constant = erroneous constant encountered
-
-middle_failed_writing_file =
-    failed to write file {$path}: {$error}"
-
-# Note: We only mention patterns here since the error can only occur with references, and those
-# are forbidden in const generics.
-middle_invalid_const_in_valtree = constant {$global_const_id} cannot be used as pattern
-    .note = constants that reference mutable or external memory cannot be used as patterns
-
-middle_layout_cycle =
-    a cycle occurred during layout computation
-
-middle_layout_normalization_failure =
-    unable to determine layout for `{$ty}` because `{$failure_ty}` cannot be normalized
-
-middle_layout_references_error =
-    the type has an unknown layout
-
-middle_layout_simd_too_many =
-    the SIMD type `{$ty}` has more elements than the limit {$max_lanes}
-
-middle_layout_simd_zero_length =
-    the SIMD type `{$ty}` has zero elements
-
-middle_layout_size_overflow =
-    values of the type `{$ty}` are too big for the target architecture
-
-middle_layout_too_generic = the type `{$ty}` does not have a fixed layout
-
-middle_layout_unknown =
-    the type `{$ty}` has an unknown layout
-
-middle_max_num_nodes_in_valtree = maximum number of nodes exceeded in constant {$global_const_id}
-
-middle_opaque_hidden_type_mismatch =
-    concrete type differs from previous defining opaque type use
-    .label = expected `{$self_ty}`, got `{$other_ty}`
-
-middle_previous_use_here =
-    previous use here
-
-middle_recursion_limit_reached =
-    reached the recursion limit finding the struct tail for `{$ty}`
-    .help = consider increasing the recursion limit by adding a `#![recursion_limit = "{$suggested_limit}"]`
-
-middle_requires_lang_item = requires `{$name}` lang_item
-
-middle_strict_coherence_needs_negative_coherence =
-    to use `strict_coherence` on this trait, the `with_negative_coherence` feature must be enabled
-    .label = due to this attribute
-
-middle_type_length_limit = reached the type-length limit while instantiating `{$instance}`
-
-middle_unsupported_union = we don't support unions yet: '{$ty_name}'
diff --git a/compiler/rustc_middle/src/error.rs b/compiler/rustc_middle/src/error.rs
index 3ff9eea8cc4bf..a5d5978916eb9 100644
--- a/compiler/rustc_middle/src/error.rs
+++ b/compiler/rustc_middle/src/error.rs
@@ -9,8 +9,8 @@ use rustc_span::{Span, Symbol};
 use crate::ty::{Instance, Ty};
 
 #[derive(Diagnostic)]
-#[diag(middle_drop_check_overflow, code = E0320)]
-#[note]
+#[diag("overflow while adding drop-check rules for `{$ty}`", code = E0320)]
+#[note("overflowed on `{$overflow_ty}`")]
 pub(crate) struct DropCheckOverflow<'tcx> {
     #[primary_span]
     pub span: Span,
@@ -19,33 +19,33 @@ pub(crate) struct DropCheckOverflow<'tcx> {
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_failed_writing_file)]
+#[diag("failed to write file {$path}: {$error}\"")]
 pub(crate) struct FailedWritingFile<'a> {
     pub path: &'a Path,
     pub error: io::Error,
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_opaque_hidden_type_mismatch)]
+#[diag("concrete type differs from previous defining opaque type use")]
 pub(crate) struct OpaqueHiddenTypeMismatch<'tcx> {
     pub self_ty: Ty<'tcx>,
     pub other_ty: Ty<'tcx>,
     #[primary_span]
-    #[label]
+    #[label("expected `{$self_ty}`, got `{$other_ty}`")]
     pub other_span: Span,
     #[subdiagnostic]
     pub sub: TypeMismatchReason,
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_unsupported_union)]
+#[diag("we don't support unions yet: '{$ty_name}'")]
 pub struct UnsupportedUnion {
     pub ty_name: String,
 }
 
 // FIXME(autodiff): I should get used somewhere
 #[derive(Diagnostic)]
-#[diag(middle_autodiff_unsafe_inner_const_ref)]
+#[diag("reading from a `Duplicated` const {$ty} is unsafe")]
 pub struct AutodiffUnsafeInnerConstRef<'tcx> {
     #[primary_span]
     pub span: Span,
@@ -54,12 +54,12 @@ pub struct AutodiffUnsafeInnerConstRef<'tcx> {
 
 #[derive(Subdiagnostic)]
 pub enum TypeMismatchReason {
-    #[label(middle_conflict_types)]
+    #[label("this expression supplies two conflicting concrete types for the same opaque type")]
     ConflictType {
         #[primary_span]
         span: Span,
     },
-    #[note(middle_previous_use_here)]
+    #[note("previous use here")]
     PreviousUse {
         #[primary_span]
         span: Span,
@@ -67,8 +67,10 @@ pub enum TypeMismatchReason {
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_recursion_limit_reached)]
-#[help]
+#[diag("reached the recursion limit finding the struct tail for `{$ty}`")]
+#[help(
+    "consider increasing the recursion limit by adding a `#![recursion_limit = \"{$suggested_limit}\"]`"
+)]
 pub(crate) struct RecursionLimitReached<'tcx> {
     #[primary_span]
     pub span: Span,
@@ -77,23 +79,25 @@ pub(crate) struct RecursionLimitReached<'tcx> {
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_const_eval_non_int)]
+#[diag("constant evaluation of enum discriminant resulted in non-integer")]
 pub(crate) struct ConstEvalNonIntError {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_strict_coherence_needs_negative_coherence)]
+#[diag(
+    "to use `strict_coherence` on this trait, the `with_negative_coherence` feature must be enabled"
+)]
 pub(crate) struct StrictCoherenceNeedsNegativeCoherence {
     #[primary_span]
     pub span: Span,
-    #[label]
+    #[label("due to this attribute")]
     pub attr_span: Option<Span>,
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_requires_lang_item)]
+#[diag("requires `{$name}` lang_item")]
 pub(crate) struct RequiresLangItem {
     #[primary_span]
     pub span: Span,
@@ -101,7 +105,9 @@ pub(crate) struct RequiresLangItem {
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_const_not_used_in_type_alias)]
+#[diag(
+    "const parameter `{$ct}` is part of concrete type but not used in parameter list for the `impl Trait` type alias"
+)]
 pub(super) struct ConstNotUsedTraitAlias {
     pub ct: String,
     #[primary_span]
@@ -133,41 +139,41 @@ impl fmt::Debug for CustomSubdiagnostic<'_> {
 
 #[derive(Diagnostic)]
 pub enum LayoutError<'tcx> {
-    #[diag(middle_layout_unknown)]
+    #[diag("the type `{$ty}` has an unknown layout")]
     Unknown { ty: Ty<'tcx> },
 
-    #[diag(middle_layout_too_generic)]
+    #[diag("the type `{$ty}` does not have a fixed layout")]
     TooGeneric { ty: Ty<'tcx> },
 
-    #[diag(middle_layout_size_overflow)]
+    #[diag("values of the type `{$ty}` are too big for the target architecture")]
     Overflow { ty: Ty<'tcx> },
 
-    #[diag(middle_layout_simd_too_many)]
+    #[diag("the SIMD type `{$ty}` has more elements than the limit {$max_lanes}")]
     SimdTooManyLanes { ty: Ty<'tcx>, max_lanes: u64 },
 
-    #[diag(middle_layout_simd_zero_length)]
+    #[diag("the SIMD type `{$ty}` has zero elements")]
     SimdZeroLength { ty: Ty<'tcx> },
 
-    #[diag(middle_layout_normalization_failure)]
+    #[diag("unable to determine layout for `{$ty}` because `{$failure_ty}` cannot be normalized")]
     NormalizationFailure { ty: Ty<'tcx>, failure_ty: String },
 
-    #[diag(middle_layout_cycle)]
+    #[diag("a cycle occurred during layout computation")]
     Cycle,
 
-    #[diag(middle_layout_references_error)]
+    #[diag("the type has an unknown layout")]
     ReferencesError,
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_erroneous_constant)]
+#[diag("erroneous constant encountered")]
 pub(crate) struct ErroneousConstant {
     #[primary_span]
     pub span: Span,
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_type_length_limit)]
-#[help(middle_consider_type_length_limit)]
+#[diag("reached the type-length limit while instantiating `{$instance}`")]
+#[help("consider adding a `#![type_length_limit=\"{$type_length}\"]` attribute to your crate")]
 pub(crate) struct TypeLengthLimit<'tcx> {
     #[primary_span]
     pub span: Span,
@@ -176,7 +182,7 @@ pub(crate) struct TypeLengthLimit<'tcx> {
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_max_num_nodes_in_valtree)]
+#[diag("maximum number of nodes exceeded in constant {$global_const_id}")]
 pub(crate) struct MaxNumNodesInValtree {
     #[primary_span]
     pub span: Span,
@@ -184,8 +190,8 @@ pub(crate) struct MaxNumNodesInValtree {
 }
 
 #[derive(Diagnostic)]
-#[diag(middle_invalid_const_in_valtree)]
-#[note]
+#[diag("constant {$global_const_id} cannot be used as pattern")]
+#[note("constants that reference mutable or external memory cannot be used as patterns")]
 pub(crate) struct InvalidConstInValtree {
     #[primary_span]
     pub span: Span,
diff --git a/compiler/rustc_middle/src/lib.rs b/compiler/rustc_middle/src/lib.rs
index 7d1b775cc4bcd..5b32d4551a16f 100644
--- a/compiler/rustc_middle/src/lib.rs
+++ b/compiler/rustc_middle/src/lib.rs
@@ -91,5 +91,3 @@ pub mod dep_graph;
 
 // Allows macros to refer to this crate as `::rustc_middle`
 extern crate self as rustc_middle;
-
-rustc_fluent_macro::fluent_messages! { "../messages.ftl" }
diff --git a/compiler/rustc_middle/src/middle/stability.rs b/compiler/rustc_middle/src/middle/stability.rs
index fe2d4b9130ed5..fce0158aa5111 100644
--- a/compiler/rustc_middle/src/middle/stability.rs
+++ b/compiler/rustc_middle/src/middle/stability.rs
@@ -4,7 +4,7 @@
 use std::num::NonZero;
 
 use rustc_ast::NodeId;
-use rustc_errors::{Applicability, Diag, EmissionGuarantee, LintBuffer};
+use rustc_errors::{Applicability, Diag, EmissionGuarantee, LintBuffer, inline_fluent};
 use rustc_feature::GateIssue;
 use rustc_hir::attrs::{DeprecatedSince, Deprecation};
 use rustc_hir::def_id::{DefId, LocalDefId};
@@ -103,7 +103,7 @@ fn deprecation_lint(is_in_effect: bool) -> &'static Lint {
 
 #[derive(Subdiagnostic)]
 #[suggestion(
-    middle_deprecated_suggestion,
+    "replace the use of the deprecated {$kind}",
     code = "{suggestion}",
     style = "verbose",
     applicability = "machine-applicable"
@@ -128,10 +128,19 @@ pub struct Deprecated {
 impl<'a, G: EmissionGuarantee> rustc_errors::LintDiagnostic<'a, G> for Deprecated {
     fn decorate_lint<'b>(self, diag: &'b mut Diag<'a, G>) {
         diag.primary_message(match &self.since_kind {
-            DeprecatedSinceKind::InEffect => crate::fluent_generated::middle_deprecated,
-            DeprecatedSinceKind::InFuture => crate::fluent_generated::middle_deprecated_in_future,
+            DeprecatedSinceKind::InEffect => inline_fluent!("use of deprecated {$kind} `{$path}`{$has_note ->
+                [true] : {$note}
+                *[other] {\"\"}
+            }"),
+            DeprecatedSinceKind::InFuture => inline_fluent!("use of {$kind} `{$path}` that will be deprecated in a future Rust version{$has_note ->
+                [true] : {$note}
+                *[other] {\"\"}
+            }"),
             DeprecatedSinceKind::InVersion(_) => {
-                crate::fluent_generated::middle_deprecated_in_version
+                inline_fluent!("use of {$kind} `{$path}` that will be deprecated in future version {$version}{$has_note ->
+                    [true] : {$note}
+                    *[other] {\"\"}
+                }")
             }
         });
         diag.arg("kind", self.kind);
diff --git a/compiler/rustc_middle/src/mir/terminator.rs b/compiler/rustc_middle/src/mir/terminator.rs
index cd447d4ed992b..e212dd43fa7d9 100644
--- a/compiler/rustc_middle/src/mir/terminator.rs
+++ b/compiler/rustc_middle/src/mir/terminator.rs
@@ -336,18 +336,26 @@ impl<O> AssertKind<O> {
     pub fn diagnostic_message(&self) -> DiagMessage {
         use AssertKind::*;
 
-        use crate::fluent_generated::*;
-
         match self {
-            BoundsCheck { .. } => middle_bounds_check,
-            Overflow(BinOp::Shl, _, _) => middle_assert_shl_overflow,
-            Overflow(BinOp::Shr, _, _) => middle_assert_shr_overflow,
-            Overflow(_, _, _) => middle_assert_op_overflow,
-            OverflowNeg(_) => middle_assert_overflow_neg,
-            DivisionByZero(_) => middle_assert_divide_by_zero,
-            RemainderByZero(_) => middle_assert_remainder_by_zero,
+            BoundsCheck { .. } => inline_fluent!(
+                "index out of bounds: the length is {$len} but the index is {$index}"
+            ),
+            Overflow(BinOp::Shl, _, _) => {
+                inline_fluent!("attempt to shift left by `{$val}`, which would overflow")
+            }
+            Overflow(BinOp::Shr, _, _) => {
+                inline_fluent!("attempt to shift right by `{$val}`, which would overflow")
+            }
+            Overflow(_, _, _) => {
+                inline_fluent!("attempt to compute `{$left} {$op} {$right}`, which would overflow")
+            }
+            OverflowNeg(_) => inline_fluent!("attempt to negate `{$val}`, which would overflow"),
+            DivisionByZero(_) => inline_fluent!("attempt to divide `{$val}` by zero"),
+            RemainderByZero(_) => inline_fluent!(
+                "attempt to calculate the remainder of `{$val}` with a divisor of zero"
+            ),
             ResumedAfterReturn(CoroutineKind::Desugared(CoroutineDesugaring::Async, _)) => {
-                middle_assert_async_resume_after_return
+                inline_fluent!("`async fn` resumed after completion")
             }
             ResumedAfterReturn(CoroutineKind::Desugared(CoroutineDesugaring::AsyncGen, _)) => {
                 todo!()
@@ -356,36 +364,42 @@ impl<O> AssertKind<O> {
                 bug!("gen blocks can be resumed after they return and will keep returning `None`")
             }
             ResumedAfterReturn(CoroutineKind::Coroutine(_)) => {
-                middle_assert_coroutine_resume_after_return
+                inline_fluent!("coroutine resumed after completion")
             }
             ResumedAfterPanic(CoroutineKind::Desugared(CoroutineDesugaring::Async, _)) => {
-                middle_assert_async_resume_after_panic
+                inline_fluent!("`async fn` resumed after panicking")
             }
             ResumedAfterPanic(CoroutineKind::Desugared(CoroutineDesugaring::AsyncGen, _)) => {
                 todo!()
             }
             ResumedAfterPanic(CoroutineKind::Desugared(CoroutineDesugaring::Gen, _)) => {
-                middle_assert_gen_resume_after_panic
+                inline_fluent!("`gen` fn or block cannot be further iterated on after it panicked")
             }
             ResumedAfterPanic(CoroutineKind::Coroutine(_)) => {
-                middle_assert_coroutine_resume_after_panic
+                inline_fluent!("coroutine resumed after panicking")
+            }
+            NullPointerDereference => inline_fluent!("null pointer dereference occurred"),
+            InvalidEnumConstruction(_) => {
+                inline_fluent!("trying to construct an enum from an invalid value `{$source}`")
             }
-            NullPointerDereference => middle_assert_null_ptr_deref,
-            InvalidEnumConstruction(_) => middle_assert_invalid_enum_construction,
             ResumedAfterDrop(CoroutineKind::Desugared(CoroutineDesugaring::Async, _)) => {
-                middle_assert_async_resume_after_drop
+                inline_fluent!("`async fn` resumed after async drop")
             }
             ResumedAfterDrop(CoroutineKind::Desugared(CoroutineDesugaring::AsyncGen, _)) => {
                 todo!()
             }
             ResumedAfterDrop(CoroutineKind::Desugared(CoroutineDesugaring::Gen, _)) => {
-                middle_assert_gen_resume_after_drop
+                inline_fluent!(
+                    "`gen` fn or block cannot be further iterated on after it async dropped"
+                )
             }
             ResumedAfterDrop(CoroutineKind::Coroutine(_)) => {
-                middle_assert_coroutine_resume_after_drop
+                inline_fluent!("coroutine resumed after async drop")
             }
 
-            MisalignedPointerDereference { .. } => middle_assert_misaligned_ptr_deref,
+            MisalignedPointerDereference { .. } => inline_fluent!(
+                "misaligned pointer dereference: address must be a multiple of {$required} but is {$found}"
+            ),
         }
     }
 
@@ -498,6 +512,7 @@ impl<'tcx> TerminatorKind<'tcx> {
 }
 
 pub use helper::*;
+use rustc_errors::inline_fluent;
 
 mod helper {
     use super::*;
diff --git a/compiler/rustc_middle/src/ty/layout.rs b/compiler/rustc_middle/src/ty/layout.rs
index 14ebcc968f7af..d3b4654a8d799 100644
--- a/compiler/rustc_middle/src/ty/layout.rs
+++ b/compiler/rustc_middle/src/ty/layout.rs
@@ -9,6 +9,7 @@ use rustc_abi::{
 use rustc_error_messages::DiagMessage;
 use rustc_errors::{
     Diag, DiagArgValue, DiagCtxtHandle, Diagnostic, EmissionGuarantee, IntoDiagArg, Level,
+    inline_fluent,
 };
 use rustc_hir::LangItem;
 use rustc_hir::def_id::DefId;
@@ -268,18 +269,25 @@ impl<'tcx> LayoutError<'tcx> {
     pub fn diagnostic_message(&self) -> DiagMessage {
         use LayoutError::*;
 
-        use crate::fluent_generated::*;
         match self {
-            Unknown(_) => middle_layout_unknown,
-            SizeOverflow(_) => middle_layout_size_overflow,
+            Unknown(_) => inline_fluent!("the type `{$ty}` has an unknown layout"),
+            SizeOverflow(_) => {
+                inline_fluent!("values of the type `{$ty}` are too big for the target architecture")
+            }
             InvalidSimd { kind: SimdLayoutError::TooManyLanes(_), .. } => {
-                middle_layout_simd_too_many
+                inline_fluent!(
+                    "the SIMD type `{$ty}` has more elements than the limit {$max_lanes}"
+                )
             }
-            InvalidSimd { kind: SimdLayoutError::ZeroLength, .. } => middle_layout_simd_zero_length,
-            TooGeneric(_) => middle_layout_too_generic,
-            NormalizationFailure(_, _) => middle_layout_normalization_failure,
-            Cycle(_) => middle_layout_cycle,
-            ReferencesError(_) => middle_layout_references_error,
+            InvalidSimd { kind: SimdLayoutError::ZeroLength, .. } => {
+                inline_fluent!("the SIMD type `{$ty}` has zero elements")
+            }
+            TooGeneric(_) => inline_fluent!("the type `{$ty}` does not have a fixed layout"),
+            NormalizationFailure(_, _) => inline_fluent!(
+                "unable to determine layout for `{$ty}` because `{$failure_ty}` cannot be normalized"
+            ),
+            Cycle(_) => inline_fluent!("a cycle occurred during layout computation"),
+            ReferencesError(_) => inline_fluent!("the type has an unknown layout"),
         }
     }