1 files changed, 865 insertions, 0 deletions
diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs
new file mode 100644
index 000000000..7f81aef1c
--- /dev/null
+++ b/compiler/rustc_mir_build/src/errors.rs
@@ -0,0 +1,865 @@
+use crate::thir::pattern::deconstruct_pat::DeconstructedPat;
+use crate::thir::pattern::MatchCheckCtxt;
+use rustc_errors::Handler;
+use rustc_errors::{
+    error_code, AddToDiagnostic, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
+    IntoDiagnostic, MultiSpan, SubdiagnosticMessage,
+};
+use rustc_hir::def::Res;
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
+use rustc_middle::thir::Pat;
+use rustc_middle::ty::{self, Ty};
+use rustc_span::{symbol::Ident, Span};
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unconditional_recursion)]
+#[help]
+pub struct UnconditionalRecursion {
+    #[label]
+    pub span: Span,
+    #[label(mir_build_unconditional_recursion_call_site_label)]
+    pub call_sites: Vec<Span>,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_call_to_unsafe_fn_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnCallToUnsafeFunctionRequiresUnsafe<'a> {
+    #[label]
+    pub span: Span,
+    pub function: &'a str,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_call_to_unsafe_fn_requires_unsafe_nameless)]
+#[note]
+pub struct UnsafeOpInUnsafeFnCallToUnsafeFunctionRequiresUnsafeNameless {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_inline_assembly_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnUseOfInlineAssemblyRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_initializing_type_with_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnInitializingTypeWithRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_mutable_static_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnUseOfMutableStaticRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_extern_static_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnUseOfExternStaticRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_deref_raw_pointer_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnDerefOfRawPointerRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_union_field_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnAccessToUnionFieldRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_mutation_of_layout_constrained_field_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnMutationOfLayoutConstrainedFieldRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_borrow_of_layout_constrained_field_requires_unsafe)]
+pub struct UnsafeOpInUnsafeFnBorrowOfLayoutConstrainedFieldRequiresUnsafe {
+    #[label]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unsafe_op_in_unsafe_fn_call_to_fn_with_requires_unsafe)]
+#[note]
+pub struct UnsafeOpInUnsafeFnCallToFunctionWithRequiresUnsafe<'a> {
+    #[label]
+    pub span: Span,
+    pub function: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_call_to_unsafe_fn_requires_unsafe, code = "E0133")]
+#[note]
+pub struct CallToUnsafeFunctionRequiresUnsafe<'a> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub function: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_call_to_unsafe_fn_requires_unsafe_nameless, code = "E0133")]
+#[note]
+pub struct CallToUnsafeFunctionRequiresUnsafeNameless {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_call_to_unsafe_fn_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = "E0133")]
+#[note]
+pub struct CallToUnsafeFunctionRequiresUnsafeUnsafeOpInUnsafeFnAllowed<'a> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub function: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(
+    mir_build_call_to_unsafe_fn_requires_unsafe_nameless_unsafe_op_in_unsafe_fn_allowed,
+    code = "E0133"
+)]
+#[note]
+pub struct CallToUnsafeFunctionRequiresUnsafeNamelessUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_inline_assembly_requires_unsafe, code = "E0133")]
+#[note]
+pub struct UseOfInlineAssemblyRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_inline_assembly_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = "E0133")]
+#[note]
+pub struct UseOfInlineAssemblyRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_initializing_type_with_requires_unsafe, code = "E0133")]
+#[note]
+pub struct InitializingTypeWithRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(
+    mir_build_initializing_type_with_requires_unsafe_unsafe_op_in_unsafe_fn_allowed,
+    code = "E0133"
+)]
+#[note]
+pub struct InitializingTypeWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_mutable_static_requires_unsafe, code = "E0133")]
+#[note]
+pub struct UseOfMutableStaticRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_mutable_static_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = "E0133")]
+#[note]
+pub struct UseOfMutableStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_extern_static_requires_unsafe, code = "E0133")]
+#[note]
+pub struct UseOfExternStaticRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_extern_static_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = "E0133")]
+#[note]
+pub struct UseOfExternStaticRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_deref_raw_pointer_requires_unsafe, code = "E0133")]
+#[note]
+pub struct DerefOfRawPointerRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_deref_raw_pointer_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = "E0133")]
+#[note]
+pub struct DerefOfRawPointerRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_union_field_requires_unsafe, code = "E0133")]
+#[note]
+pub struct AccessToUnionFieldRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_union_field_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = "E0133")]
+#[note]
+pub struct AccessToUnionFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_mutation_of_layout_constrained_field_requires_unsafe, code = "E0133")]
+#[note]
+pub struct MutationOfLayoutConstrainedFieldRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(
+    mir_build_mutation_of_layout_constrained_field_requires_unsafe_unsafe_op_in_unsafe_fn_allowed,
+    code = "E0133"
+)]
+#[note]
+pub struct MutationOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_borrow_of_layout_constrained_field_requires_unsafe, code = "E0133")]
+#[note]
+pub struct BorrowOfLayoutConstrainedFieldRequiresUnsafe {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(
+    mir_build_borrow_of_layout_constrained_field_requires_unsafe_unsafe_op_in_unsafe_fn_allowed,
+    code = "E0133"
+)]
+#[note]
+pub struct BorrowOfLayoutConstrainedFieldRequiresUnsafeUnsafeOpInUnsafeFnAllowed {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_call_to_fn_with_requires_unsafe, code = "E0133")]
+#[note]
+pub struct CallToFunctionWithRequiresUnsafe<'a> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub function: &'a str,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_call_to_fn_with_requires_unsafe_unsafe_op_in_unsafe_fn_allowed, code = "E0133")]
+#[note]
+pub struct CallToFunctionWithRequiresUnsafeUnsafeOpInUnsafeFnAllowed<'a> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub function: &'a str,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unused_unsafe)]
+pub struct UnusedUnsafe {
+    #[label]
+    pub span: Span,
+    #[subdiagnostic]
+    pub enclosing: Option<UnusedUnsafeEnclosing>,
+}
+
+#[derive(Subdiagnostic)]
+pub enum UnusedUnsafeEnclosing {
+    #[label(mir_build_unused_unsafe_enclosing_block_label)]
+    Block {
+        #[primary_span]
+        span: Span,
+    },
+    #[label(mir_build_unused_unsafe_enclosing_fn_label)]
+    Function {
+        #[primary_span]
+        span: Span,
+    },
+}
+
+pub(crate) struct NonExhaustivePatternsTypeNotEmpty<'p, 'tcx, 'm> {
+    pub cx: &'m MatchCheckCtxt<'p, 'tcx>,
+    pub expr_span: Span,
+    pub span: Span,
+    pub ty: Ty<'tcx>,
+}
+
+impl<'a> IntoDiagnostic<'a> for NonExhaustivePatternsTypeNotEmpty<'_, '_, '_> {
+    fn into_diagnostic(self, handler: &'a Handler) -> DiagnosticBuilder<'_, ErrorGuaranteed> {
+        let mut diag = handler.struct_span_err_with_code(
+            self.span,
+            rustc_errors::fluent::mir_build_non_exhaustive_patterns_type_not_empty,
+            error_code!(E0004),
+        );
+
+        let peeled_ty = self.ty.peel_refs();
+        diag.set_arg("ty", self.ty);
+        diag.set_arg("peeled_ty", peeled_ty);
+
+        if let ty::Adt(def, _) = peeled_ty.kind() {
+            let def_span = self
+                .cx
+                .tcx
+                .hir()
+                .get_if_local(def.did())
+                .and_then(|node| node.ident())
+                .map(|ident| ident.span)
+                .unwrap_or_else(|| self.cx.tcx.def_span(def.did()));
+
+            // workaround to make test pass
+            let mut span: MultiSpan = def_span.into();
+            span.push_span_label(def_span, "");
+
+            diag.span_note(span, rustc_errors::fluent::def_note);
+        }
+
+        let is_variant_list_non_exhaustive = match self.ty.kind() {
+            ty::Adt(def, _) if def.is_variant_list_non_exhaustive() && !def.did().is_local() => {
+                true
+            }
+            _ => false,
+        };
+
+        if is_variant_list_non_exhaustive {
+            diag.note(rustc_errors::fluent::non_exhaustive_type_note);
+        } else {
+            diag.note(rustc_errors::fluent::type_note);
+        }
+
+        if let ty::Ref(_, sub_ty, _) = self.ty.kind() {
+            if !sub_ty.is_inhabited_from(self.cx.tcx, self.cx.module, self.cx.param_env) {
+                diag.note(rustc_errors::fluent::reference_note);
+            }
+        }
+
+        let mut suggestion = None;
+        let sm = self.cx.tcx.sess.source_map();
+        if self.span.eq_ctxt(self.expr_span) {
+            // Get the span for the empty match body `{}`.
+            let (indentation, more) = if let Some(snippet) = sm.indentation_before(self.span) {
+                (format!("\n{}", snippet), "    ")
+            } else {
+                (" ".to_string(), "")
+            };
+            suggestion = Some((
+                self.span.shrink_to_hi().with_hi(self.expr_span.hi()),
+                format!(
+                    " {{{indentation}{more}_ => todo!(),{indentation}}}",
+                    indentation = indentation,
+                    more = more,
+                ),
+            ));
+        }
+
+        if let Some((span, sugg)) = suggestion {
+            diag.span_suggestion_verbose(
+                span,
+                rustc_errors::fluent::suggestion,
+                sugg,
+                Applicability::HasPlaceholders,
+            );
+        } else {
+            diag.help(rustc_errors::fluent::help);
+        }
+
+        diag
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_static_in_pattern, code = "E0158")]
+pub struct StaticInPattern {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_assoc_const_in_pattern, code = "E0158")]
+pub struct AssocConstInPattern {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_const_param_in_pattern, code = "E0158")]
+pub struct ConstParamInPattern {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_non_const_path, code = "E0080")]
+pub struct NonConstPath {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_unreachable_pattern)]
+pub struct UnreachablePattern {
+    #[label]
+    pub span: Option<Span>,
+    #[label(catchall_label)]
+    pub catchall: Option<Span>,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_const_pattern_depends_on_generic_parameter)]
+pub struct ConstPatternDependsOnGenericParameter {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_could_not_eval_const_pattern)]
+pub struct CouldNotEvalConstPattern {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_lower_range_bound_must_be_less_than_or_equal_to_upper, code = "E0030")]
+pub struct LowerRangeBoundMustBeLessThanOrEqualToUpper {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    #[note(teach_note)]
+    pub teach: Option<()>,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_literal_in_range_out_of_bounds)]
+pub struct LiteralOutOfRange<'tcx> {
+    #[primary_span]
+    #[label]
+    pub span: Span,
+    pub ty: Ty<'tcx>,
+    pub max: u128,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_lower_range_bound_must_be_less_than_upper, code = "E0579")]
+pub struct LowerRangeBoundMustBeLessThanUpper {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_leading_irrefutable_let_patterns)]
+#[note]
+#[help]
+pub struct LeadingIrrefutableLetPatterns {
+    pub count: usize,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_trailing_irrefutable_let_patterns)]
+#[note]
+#[help]
+pub struct TrailingIrrefutableLetPatterns {
+    pub count: usize,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_bindings_with_variant_name, code = "E0170")]
+pub struct BindingsWithVariantName {
+    #[suggestion(code = "{ty_path}::{ident}", applicability = "machine-applicable")]
+    pub suggestion: Option<Span>,
+    pub ty_path: String,
+    pub ident: Ident,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_irrefutable_let_patterns_generic_let)]
+#[note]
+#[help]
+pub struct IrrefutableLetPatternsGenericLet {
+    pub count: usize,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_irrefutable_let_patterns_if_let)]
+#[note]
+#[help]
+pub struct IrrefutableLetPatternsIfLet {
+    pub count: usize,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_irrefutable_let_patterns_if_let_guard)]
+#[note]
+#[help]
+pub struct IrrefutableLetPatternsIfLetGuard {
+    pub count: usize,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_irrefutable_let_patterns_let_else)]
+#[note]
+#[help]
+pub struct IrrefutableLetPatternsLetElse {
+    pub count: usize,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_irrefutable_let_patterns_while_let)]
+#[note]
+#[help]
+pub struct IrrefutableLetPatternsWhileLet {
+    pub count: usize,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_borrow_of_moved_value)]
+pub struct BorrowOfMovedValue<'tcx> {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    #[label(occurs_because_label)]
+    pub binding_span: Span,
+    #[label(value_borrowed_label)]
+    pub conflicts_ref: Vec<Span>,
+    pub name: Ident,
+    pub ty: Ty<'tcx>,
+    #[suggestion(code = "ref ", applicability = "machine-applicable")]
+    pub suggest_borrowing: Option<Span>,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_multiple_mut_borrows)]
+pub struct MultipleMutBorrows {
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub binding_span: Span,
+    #[subdiagnostic]
+    pub occurences: Vec<MultipleMutBorrowOccurence>,
+    pub name: Ident,
+}
+
+#[derive(Subdiagnostic)]
+pub enum MultipleMutBorrowOccurence {
+    #[label(mutable_borrow)]
+    Mutable {
+        #[primary_span]
+        span: Span,
+        name_mut: Ident,
+    },
+    #[label(immutable_borrow)]
+    Immutable {
+        #[primary_span]
+        span: Span,
+        name_immut: Ident,
+    },
+    #[label(moved)]
+    Moved {
+        #[primary_span]
+        span: Span,
+        name_moved: Ident,
+    },
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_union_pattern)]
+pub struct UnionPattern {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_type_not_structural)]
+pub struct TypeNotStructural<'tcx> {
+    #[primary_span]
+    pub span: Span,
+    pub non_sm_ty: Ty<'tcx>,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_invalid_pattern)]
+pub struct InvalidPattern<'tcx> {
+    #[primary_span]
+    pub span: Span,
+    pub non_sm_ty: Ty<'tcx>,
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_unsized_pattern)]
+pub struct UnsizedPattern<'tcx> {
+    #[primary_span]
+    pub span: Span,
+    pub non_sm_ty: Ty<'tcx>,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_float_pattern)]
+pub struct FloatPattern;
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_pointer_pattern)]
+pub struct PointerPattern;
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_indirect_structural_match)]
+pub struct IndirectStructuralMatch<'tcx> {
+    pub non_sm_ty: Ty<'tcx>,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_nontrivial_structural_match)]
+pub struct NontrivialStructuralMatch<'tcx> {
+    pub non_sm_ty: Ty<'tcx>,
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_overlapping_range_endpoints)]
+#[note]
+pub struct OverlappingRangeEndpoints<'tcx> {
+    #[label(range)]
+    pub range: Span,
+    #[subdiagnostic]
+    pub overlap: Vec<Overlap<'tcx>>,
+}
+
+pub struct Overlap<'tcx> {
+    pub span: Span,
+    pub range: Pat<'tcx>,
+}
+
+impl<'tcx> AddToDiagnostic for Overlap<'tcx> {
+    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
+    where
+        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
+    {
+        let Overlap { span, range } = self;
+
+        // FIXME(mejrs) unfortunately `#[derive(LintDiagnostic)]`
+        // does not support `#[subdiagnostic(eager)]`...
+        let message = format!("this range overlaps on `{range}`...");
+        diag.span_label(span, message);
+    }
+}
+
+#[derive(LintDiagnostic)]
+#[diag(mir_build_non_exhaustive_omitted_pattern)]
+#[help]
+#[note]
+pub(crate) struct NonExhaustiveOmittedPattern<'tcx> {
+    pub scrut_ty: Ty<'tcx>,
+    #[subdiagnostic]
+    pub uncovered: Uncovered<'tcx>,
+}
+
+#[derive(Subdiagnostic)]
+#[label(mir_build_uncovered)]
+pub(crate) struct Uncovered<'tcx> {
+    #[primary_span]
+    span: Span,
+    count: usize,
+    witness_1: Pat<'tcx>,
+    witness_2: Pat<'tcx>,
+    witness_3: Pat<'tcx>,
+    remainder: usize,
+}
+
+impl<'tcx> Uncovered<'tcx> {
+    pub fn new<'p>(
+        span: Span,
+        cx: &MatchCheckCtxt<'p, 'tcx>,
+        witnesses: Vec<DeconstructedPat<'p, 'tcx>>,
+    ) -> Self {
+        let witness_1 = witnesses.get(0).unwrap().to_pat(cx);
+        Self {
+            span,
+            count: witnesses.len(),
+            // Substitute dummy values if witnesses is smaller than 3. These will never be read.
+            witness_2: witnesses.get(1).map(|w| w.to_pat(cx)).unwrap_or_else(|| witness_1.clone()),
+            witness_3: witnesses.get(2).map(|w| w.to_pat(cx)).unwrap_or_else(|| witness_1.clone()),
+            witness_1,
+            remainder: witnesses.len().saturating_sub(3),
+        }
+    }
+}
+
+#[derive(Diagnostic)]
+#[diag(mir_build_pattern_not_covered, code = "E0005")]
+pub(crate) struct PatternNotCovered<'s, 'tcx> {
+    #[primary_span]
+    pub span: Span,
+    pub origin: &'s str,
+    #[subdiagnostic]
+    pub uncovered: Uncovered<'tcx>,
+    #[subdiagnostic]
+    pub inform: Option<Inform>,
+    #[subdiagnostic]
+    pub interpreted_as_const: Option<InterpretedAsConst>,
+    #[subdiagnostic]
+    pub adt_defined_here: Option<AdtDefinedHere<'tcx>>,
+    #[note(pattern_ty)]
+    pub _p: (),
+    pub pattern_ty: Ty<'tcx>,
+    #[subdiagnostic]
+    pub let_suggestion: Option<SuggestLet>,
+    #[subdiagnostic]
+    pub misc_suggestion: Option<MiscPatternSuggestion>,
+    #[subdiagnostic]
+    pub res_defined_here: Option<ResDefinedHere>,
+}
+
+#[derive(Subdiagnostic)]
+#[note(mir_build_inform_irrefutable)]
+#[note(mir_build_more_information)]
+pub struct Inform;
+
+pub struct AdtDefinedHere<'tcx> {
+    pub adt_def_span: Span,
+    pub ty: Ty<'tcx>,
+    pub variants: Vec<Variant>,
+}
+
+pub struct Variant {
+    pub span: Span,
+}
+
+impl<'tcx> AddToDiagnostic for AdtDefinedHere<'tcx> {
+    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
+    where
+        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
+    {
+        diag.set_arg("ty", self.ty);
+        let mut spans = MultiSpan::from(self.adt_def_span);
+
+        for Variant { span } in self.variants {
+            spans.push_span_label(span, rustc_errors::fluent::mir_build_variant_defined_here);
+        }
+
+        diag.span_note(spans, rustc_errors::fluent::mir_build_adt_defined_here);
+    }
+}
+
+#[derive(Subdiagnostic)]
+#[label(mir_build_res_defined_here)]
+pub struct ResDefinedHere {
+    #[primary_span]
+    pub def_span: Span,
+    pub res: Res,
+}
+
+#[derive(Subdiagnostic)]
+#[suggestion(
+    mir_build_interpreted_as_const,
+    code = "{variable}_var",
+    applicability = "maybe-incorrect"
+)]
+#[label(mir_build_confused)]
+pub struct InterpretedAsConst {
+    #[primary_span]
+    pub span: Span,
+    pub article: &'static str,
+    pub variable: String,
+    pub res: Res,
+}
+
+#[derive(Subdiagnostic)]
+pub enum SuggestLet {
+    #[multipart_suggestion(mir_build_suggest_if_let, applicability = "has-placeholders")]
+    If {
+        #[suggestion_part(code = "if ")]
+        start_span: Span,
+        #[suggestion_part(code = " {{ todo!() }}")]
+        semi_span: Span,
+        count: usize,
+    },
+    #[suggestion(
+        mir_build_suggest_let_else,
+        code = " else {{ todo!() }}",
+        applicability = "has-placeholders"
+    )]
+    Else {
+        #[primary_span]
+        end_span: Span,
+        count: usize,
+    },
+}
+
+#[derive(Subdiagnostic)]
+pub enum MiscPatternSuggestion {
+    #[suggestion(
+        mir_build_suggest_attempted_int_lit,
+        code = "_",
+        applicability = "maybe-incorrect"
+    )]
+    AttemptedIntegerLiteral {
+        #[primary_span]
+        start_span: Span,
+    },
+}