diff --git a/Cargo.lock b/Cargo.lock
index ebacd32db4fc7..a7905a12e0feb 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4213,11 +4213,14 @@ dependencies = [
  "regex",
  "rustc_ast",
  "rustc_data_structures",
+ "rustc_errors",
  "rustc_graphviz",
  "rustc_hir",
  "rustc_index",
+ "rustc_macros",
  "rustc_middle",
  "rustc_serialize",
+ "rustc_session",
  "rustc_span",
  "rustc_target",
  "smallvec",
diff --git a/compiler/rustc_error_messages/locales/en-US/mir_dataflow.ftl b/compiler/rustc_error_messages/locales/en-US/mir_dataflow.ftl
new file mode 100644
index 0000000000000..9885415250883
--- /dev/null
+++ b/compiler/rustc_error_messages/locales/en-US/mir_dataflow.ftl
@@ -0,0 +1,29 @@
+mir_dataflow_path_must_end_in_filename =
+    path must end in a filename
+
+mir_dataflow_unknown_formatter =
+    unknown formatter
+
+mir_dataflow_duplicate_values_for =
+    duplicate values for `{$name}`
+
+mir_dataflow_requires_an_argument =
+    `{$name}` requires an argument
+
+mir_dataflow_stop_after_dataflow_ended_compilation =
+    stop_after_dataflow ended compilation
+
+mir_dataflow_peek_must_be_place_or_ref_place =
+    rustc_peek: argument expression must be either `place` or `&place`
+
+mir_dataflow_peek_must_be_not_temporary =
+    dataflow::sanity_check cannot feed a non-temp to rustc_peek
+
+mir_dataflow_peek_bit_not_set =
+    rustc_peek: bit not set
+
+mir_dataflow_peek_argument_not_a_local =
+    rustc_peek: argument was not a local
+
+mir_dataflow_peek_argument_untracked =
+    rustc_peek: argument untracked
diff --git a/compiler/rustc_error_messages/src/lib.rs b/compiler/rustc_error_messages/src/lib.rs
index 3569c7f063064..52451306bcd4c 100644
--- a/compiler/rustc_error_messages/src/lib.rs
+++ b/compiler/rustc_error_messages/src/lib.rs
@@ -43,6 +43,7 @@ fluent_messages! {
     passes => "../locales/en-US/passes.ftl",
     privacy => "../locales/en-US/privacy.ftl",
     typeck => "../locales/en-US/typeck.ftl",
+    mir_dataflow => "../locales/en-US/mir_dataflow.ftl",
 }
 
 pub use fluent_generated::{self as fluent, DEFAULT_LOCALE_RESOURCES};
diff --git a/compiler/rustc_mir_dataflow/Cargo.toml b/compiler/rustc_mir_dataflow/Cargo.toml
index baf9735fbc846..385e9ba748fb9 100644
--- a/compiler/rustc_mir_dataflow/Cargo.toml
+++ b/compiler/rustc_mir_dataflow/Cargo.toml
@@ -13,10 +13,13 @@ smallvec = { version = "1.8.1", features = ["union", "may_dangle"] }
 tracing = "0.1"
 rustc_ast = { path = "../rustc_ast" }
 rustc_data_structures = { path = "../rustc_data_structures" }
+rustc_errors = { path = "../rustc_errors" }
 rustc_graphviz = { path = "../rustc_graphviz" }
 rustc_hir = { path = "../rustc_hir" }
 rustc_index = { path = "../rustc_index" }
+rustc_macros = { path = "../rustc_macros" }
 rustc_middle = { path = "../rustc_middle" }
 rustc_serialize = { path = "../rustc_serialize" }
+rustc_session = { path = "../rustc_session" }
 rustc_target = { path = "../rustc_target" }
 rustc_span = { path = "../rustc_span" }
diff --git a/compiler/rustc_mir_dataflow/src/errors.rs b/compiler/rustc_mir_dataflow/src/errors.rs
new file mode 100644
index 0000000000000..cc14257876c5c
--- /dev/null
+++ b/compiler/rustc_mir_dataflow/src/errors.rs
@@ -0,0 +1,71 @@
+use rustc_macros::SessionDiagnostic;
+use rustc_span::{Span, Symbol};
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::path_must_end_in_filename)]
+pub(crate) struct PathMustEndInFilename {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::unknown_formatter)]
+pub(crate) struct UnknownFormatter {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::duplicate_values_for)]
+pub(crate) struct DuplicateValuesFor {
+    #[primary_span]
+    pub span: Span,
+    pub name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::requires_an_argument)]
+pub(crate) struct RequiresAnArgument {
+    #[primary_span]
+    pub span: Span,
+    pub name: Symbol,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::stop_after_dataflow_ended_compilation)]
+pub(crate) struct StopAfterDataFlowEndedCompilation;
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::peek_must_be_place_or_ref_place)]
+pub(crate) struct PeekMustBePlaceOrRefPlace {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::peek_must_be_not_temporary)]
+pub(crate) struct PeekMustBeNotTemporary {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::peek_bit_not_set)]
+pub(crate) struct PeekBitNotSet {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::peek_argument_not_a_local)]
+pub(crate) struct PeekArgumentNotALocal {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(SessionDiagnostic)]
+#[diag(mir_dataflow::peek_argument_untracked)]
+pub(crate) struct PeekArgumentUntracked {
+    #[primary_span]
+    pub span: Span,
+}
diff --git a/compiler/rustc_mir_dataflow/src/framework/engine.rs b/compiler/rustc_mir_dataflow/src/framework/engine.rs
index f374658ceb691..112204c7599be 100644
--- a/compiler/rustc_mir_dataflow/src/framework/engine.rs
+++ b/compiler/rustc_mir_dataflow/src/framework/engine.rs
@@ -1,5 +1,8 @@
 //! A solver for dataflow problems.
 
+use crate::errors::{
+    DuplicateValuesFor, PathMustEndInFilename, RequiresAnArgument, UnknownFormatter,
+};
 use crate::framework::BitSetExt;
 
 use std::ffi::OsString;
@@ -347,7 +350,7 @@ impl RustcMirAttrs {
                     match path.file_name() {
                         Some(_) => Ok(path),
                         None => {
-                            tcx.sess.span_err(attr.span(), "path must end in a filename");
+                            tcx.sess.emit_err(PathMustEndInFilename { span: attr.span() });
                             Err(())
                         }
                     }
@@ -356,7 +359,7 @@ impl RustcMirAttrs {
                 Self::set_field(&mut ret.formatter, tcx, &attr, |s| match s {
                     sym::gen_kill | sym::two_phase => Ok(s),
                     _ => {
-                        tcx.sess.span_err(attr.span(), "unknown formatter");
+                        tcx.sess.emit_err(UnknownFormatter { span: attr.span() });
                         Err(())
                     }
                 })
@@ -377,8 +380,7 @@ impl RustcMirAttrs {
         mapper: impl FnOnce(Symbol) -> Result<T, ()>,
     ) -> Result<(), ()> {
         if field.is_some() {
-            tcx.sess
-                .span_err(attr.span(), &format!("duplicate values for `{}`", attr.name_or_empty()));
+            tcx.sess.emit_err(DuplicateValuesFor { span: attr.span(), name: attr.name_or_empty() });
 
             return Err(());
         }
@@ -387,8 +389,7 @@ impl RustcMirAttrs {
             *field = Some(mapper(s)?);
             Ok(())
         } else {
-            tcx.sess
-                .span_err(attr.span(), &format!("`{}` requires an argument", attr.name_or_empty()));
+            tcx.sess.emit_err(RequiresAnArgument { span: attr.span(), name: attr.name_or_empty() });
             Err(())
         }
     }
diff --git a/compiler/rustc_mir_dataflow/src/lib.rs b/compiler/rustc_mir_dataflow/src/lib.rs
index 5793a286bd03d..62b712f7b8dbd 100644
--- a/compiler/rustc_mir_dataflow/src/lib.rs
+++ b/compiler/rustc_mir_dataflow/src/lib.rs
@@ -7,6 +7,8 @@
 #![feature(stmt_expr_attributes)]
 #![feature(trusted_step)]
 #![recursion_limit = "256"]
+#![deny(rustc::untranslatable_diagnostic)]
+#![deny(rustc::diagnostic_outside_of_impl)]
 
 #[macro_use]
 extern crate tracing;
@@ -33,6 +35,7 @@ use self::move_paths::MoveData;
 
 pub mod drop_flag_effects;
 pub mod elaborate_drops;
+mod errors;
 mod framework;
 pub mod impls;
 pub mod move_paths;
diff --git a/compiler/rustc_mir_dataflow/src/rustc_peek.rs b/compiler/rustc_mir_dataflow/src/rustc_peek.rs
index f2471f37a5266..5fb7cb6584beb 100644
--- a/compiler/rustc_mir_dataflow/src/rustc_peek.rs
+++ b/compiler/rustc_mir_dataflow/src/rustc_peek.rs
@@ -6,6 +6,10 @@ use rustc_middle::mir::MirPass;
 use rustc_middle::mir::{self, Body, Local, Location};
 use rustc_middle::ty::{self, Ty, TyCtxt};
 
+use crate::errors::{
+    PeekArgumentNotALocal, PeekArgumentUntracked, PeekBitNotSet, PeekMustBeNotTemporary,
+    PeekMustBePlaceOrRefPlace, StopAfterDataFlowEndedCompilation,
+};
 use crate::framework::BitSetExt;
 use crate::impls::{
     DefinitelyInitializedPlaces, MaybeInitializedPlaces, MaybeLiveLocals, MaybeUninitializedPlaces,
@@ -64,7 +68,7 @@ impl<'tcx> MirPass<'tcx> for SanityCheck {
         }
 
         if has_rustc_mir_with(tcx, def_id, sym::stop_after_dataflow).is_some() {
-            tcx.sess.fatal("stop_after_dataflow ended compilation");
+            tcx.sess.emit_fatal(StopAfterDataFlowEndedCompilation);
         }
     }
 }
@@ -133,9 +137,7 @@ pub fn sanity_check_via_rustc_peek<'tcx, A>(
             }
 
             _ => {
-                let msg = "rustc_peek: argument expression \
-                           must be either `place` or `&place`";
-                tcx.sess.span_err(call.span, msg);
+                tcx.sess.emit_err(PeekMustBePlaceOrRefPlace { span: call.span });
             }
         }
     }
@@ -204,18 +206,12 @@ impl PeekCall {
                         if let Some(local) = place.as_local() {
                             local
                         } else {
-                            tcx.sess.diagnostic().span_err(
-                                span,
-                                "dataflow::sanity_check cannot feed a non-temp to rustc_peek.",
-                            );
+                            tcx.sess.emit_err(PeekMustBeNotTemporary { span });
                             return None;
                         }
                     }
                     _ => {
-                        tcx.sess.diagnostic().span_err(
-                            span,
-                            "dataflow::sanity_check cannot feed a non-temp to rustc_peek.",
-                        );
+                        tcx.sess.emit_err(PeekMustBeNotTemporary { span });
                         return None;
                     }
                 };
@@ -255,12 +251,12 @@ where
                 let bit_state = flow_state.contains(peek_mpi);
                 debug!("rustc_peek({:?} = &{:?}) bit_state: {}", call.arg, place, bit_state);
                 if !bit_state {
-                    tcx.sess.span_err(call.span, "rustc_peek: bit not set");
+                    tcx.sess.emit_err(PeekBitNotSet { span: call.span });
                 }
             }
 
             LookupResult::Parent(..) => {
-                tcx.sess.span_err(call.span, "rustc_peek: argument untracked");
+                tcx.sess.emit_err(PeekArgumentUntracked { span: call.span });
             }
         }
     }
@@ -276,12 +272,12 @@ impl<'tcx> RustcPeekAt<'tcx> for MaybeLiveLocals {
     ) {
         info!(?place, "peek_at");
         let Some(local) = place.as_local() else {
-            tcx.sess.span_err(call.span, "rustc_peek: argument was not a local");
+            tcx.sess.emit_err(PeekArgumentNotALocal { span: call.span });
             return;
         };
 
         if !flow_state.contains(local) {
-            tcx.sess.span_err(call.span, "rustc_peek: bit not set");
+            tcx.sess.emit_err(PeekBitNotSet { span: call.span });
         }
     }
 }