Validation and other things

compiler/rustc_hir_analysis/messages.ftl

@@ -37,6 +37,8 @@ hir_analysis_auto_deref_reached_recursion_limit = reached the recursion limit wh
     .label = deref recursion limit reached
     .help = consider increasing the recursion limit by adding a `#![recursion_limit = "{$suggested_limit}"]` attribute to your crate (`{$crate_name}`)
 
+hir_analysis_bad_precise_capture = expected {$kind} parameter in `use<...>` precise captures list, found {$found}
+
 hir_analysis_cannot_capture_late_bound_const =
     cannot capture late-bound const parameter in {$what}
     .label = parameter defined here
@@ -214,6 +216,10 @@ hir_analysis_late_bound_lifetime_in_apit = `impl Trait` can only mention lifetim
 hir_analysis_late_bound_type_in_apit = `impl Trait` can only mention type parameters from an fn or impl
     .label = type parameter declared here
 
+hir_analysis_lifetime_not_captured = `impl Trait` captures lifetime parameter, but it is not mentioned in `use<...>` precise captures list
+    .label = lifetime captured due to being mentioned in the bounds of the `impl Trait`
+    .param_label = this lifetime parameter is captured
+
 hir_analysis_lifetimes_or_bounds_mismatch_on_trait =
     lifetime parameters or bounds on {$item_kind} `{$ident}` do not match the trait declaration
     .label = lifetimes do not match {$item_kind} in trait
@@ -339,6 +345,10 @@ hir_analysis_param_in_ty_of_assoc_const_binding =
         *[normal] the {$param_def_kind} `{$param_name}` is defined here
     }
 
+hir_analysis_param_not_captured = `impl Trait` must mention all {$kind} parameters in scope
+    .label = {$kind} parameter is implicitly captured by this `impl Trait`
+    .note = currently, all {$kind} parameters are required to be mentioned in the precise captures list
+
 hir_analysis_paren_sugar_attribute = the `#[rustc_paren_sugar]` attribute is a temporary means of controlling which traits can use parenthetical notation
     .help = add `#![feature(unboxed_closures)]` to the crate attributes to use it
 

compiler/rustc_hir_analysis/src/check/check.rs

@@ -1,10 +1,10 @@
 use crate::check::intrinsicck::InlineAsmCtxt;
-use crate::errors::LinkageType;
 
 use super::compare_impl_item::check_type_bounds;
 use super::compare_impl_item::{compare_impl_method, compare_impl_ty};
 use super::*;
 use rustc_attr as attr;
+use rustc_data_structures::unord::UnordSet;
 use rustc_errors::{codes::*, MultiSpan};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind};
@@ -12,6 +12,7 @@ use rustc_hir::Node;
 use rustc_infer::infer::{RegionVariableOrigin, TyCtxtInferExt};
 use rustc_infer::traits::{Obligation, TraitEngineExt as _};
 use rustc_lint_defs::builtin::REPR_TRANSPARENT_EXTERNAL_PRIVATE_FIELDS;
+use rustc_middle::middle::resolve_bound_vars::ResolvedArg;
 use rustc_middle::middle::stability::EvalResult;
 use rustc_middle::traits::ObligationCauseCode;
 use rustc_middle::ty::fold::BottomUpFolder;
@@ -474,6 +475,94 @@ fn sanity_check_found_hidden_type<'tcx>(
     }
 }
 
+fn check_opaque_precise_captures<'tcx>(tcx: TyCtxt<'tcx>, opaque_def_id: LocalDefId) {
+    let hir::OpaqueTy { precise_capturing_args, .. } =
+        *tcx.hir_node_by_def_id(opaque_def_id).expect_item().expect_opaque_ty();
+    let Some(precise_capturing_args) = precise_capturing_args else {
+        // No precise capturing args; nothing to validate
+        return;
+    };
+
+    let mut expected_captures = UnordSet::default();
+    for arg in precise_capturing_args {
+        match *arg {
+            hir::PreciseCapturingArg::Lifetime(&hir::Lifetime { hir_id, .. })
+            | hir::PreciseCapturingArg::Param(_, hir_id) => match tcx.named_bound_var(hir_id) {
+                Some(ResolvedArg::EarlyBound(def_id)) => {
+                    expected_captures.insert(def_id);
+                }
+                _ => {
+                    tcx.dcx().span_delayed_bug(
+                        tcx.hir().span(hir_id),
+                        "parameter should have been resolved",
+                    );
+                }
+            },
+        }
+    }
+
+    let variances = tcx.variances_of(opaque_def_id);
+    let mut def_id = Some(opaque_def_id.to_def_id());
+    while let Some(generics) = def_id {
+        let generics = tcx.generics_of(generics);
+        def_id = generics.parent;
+
+        for param in &generics.params {
+            if expected_captures.contains(&param.def_id) {
+                assert_eq!(
+                    variances[param.index as usize],
+                    ty::Invariant,
+                    "precise captured param should be invariant"
+                );
+                continue;
+            }
+
+            match param.kind {
+                ty::GenericParamDefKind::Lifetime => {
+                    // Check if the lifetime param was captured but isn't named in the precise captures list.
+                    if variances[param.index as usize] == ty::Invariant {
+                        let param_span =
+                            if let ty::ReEarlyParam(ty::EarlyParamRegion { def_id, .. })
+                            | ty::ReLateParam(ty::LateParamRegion {
+                                bound_region: ty::BoundRegionKind::BrNamed(def_id, _),
+                                ..
+                            }) = *tcx
+                                .map_opaque_lifetime_to_parent_lifetime(param.def_id.expect_local())
+                            {
+                                Some(tcx.def_span(def_id))
+                            } else {
+                                None
+                            };
+                        // FIXME(precise_capturing): Structured suggestion for this would be useful
+                        tcx.dcx().emit_err(errors::LifetimeNotCaptured {
+                            use_span: tcx.def_span(param.def_id),
+                            param_span,
+                            opaque_span: tcx.def_span(opaque_def_id),
+                        });
+                        continue;
+                    }
+                }
+                ty::GenericParamDefKind::Type { .. } => {
+                    // FIXME(precise_capturing): Structured suggestion for this would be useful
+                    tcx.dcx().emit_err(errors::ParamNotCaptured {
+                        param_span: tcx.def_span(param.def_id),
+                        opaque_span: tcx.def_span(opaque_def_id),
+                        kind: "type",
+                    });
+                }
+                ty::GenericParamDefKind::Const { .. } => {
+                    // FIXME(precise_capturing): Structured suggestion for this would be useful
+                    tcx.dcx().emit_err(errors::ParamNotCaptured {
+                        param_span: tcx.def_span(param.def_id),
+                        opaque_span: tcx.def_span(opaque_def_id),
+                        kind: "const",
+                    });
+                }
+            }
+        }
+    }
+}
+
 fn is_enum_of_nonnullable_ptr<'tcx>(
     tcx: TyCtxt<'tcx>,
     adt_def: AdtDef<'tcx>,
@@ -499,7 +588,7 @@ fn check_static_linkage(tcx: TyCtxt<'_>, def_id: LocalDefId) {
             ty::Adt(adt_def, args) => !is_enum_of_nonnullable_ptr(tcx, *adt_def, *args),
             _ => true,
         } {
-            tcx.dcx().emit_err(LinkageType { span: tcx.def_span(def_id) });
+            tcx.dcx().emit_err(errors::LinkageType { span: tcx.def_span(def_id) });
         }
     }
 }
@@ -566,6 +655,8 @@ pub(crate) fn check_item_type(tcx: TyCtxt<'_>, def_id: LocalDefId) {
             check_union(tcx, def_id);
         }
         DefKind::OpaqueTy => {
+            check_opaque_precise_captures(tcx, def_id);
+
             let origin = tcx.opaque_type_origin(def_id);
             if let hir::OpaqueTyOrigin::FnReturn(fn_def_id)
             | hir::OpaqueTyOrigin::AsyncFn(fn_def_id) = origin

compiler/rustc_hir_analysis/src/collect/resolve_bound_vars.rs

@@ -569,7 +569,13 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                 LifetimeName::Error => {}
                 LifetimeName::ImplicitObjectLifetimeDefault
                 | LifetimeName::Infer
-                | LifetimeName::Static => todo!("TODO: Error on invalid lifetime"),
+                | LifetimeName::Static => {
+                    self.tcx.dcx().emit_err(errors::BadPreciseCapture {
+                        span: lt.ident.span,
+                        kind: "lifetime",
+                        found: format!("`{}`", lt.ident.name),
+                    });
+                }
             },
             hir::PreciseCapturingArg::Param(res, hir_id) => match res {
                 Res::Def(DefKind::TyParam | DefKind::ConstParam, def_id)
@@ -577,7 +583,10 @@ impl<'a, 'tcx> Visitor<'tcx> for BoundVarContext<'a, 'tcx> {
                     self.resolve_type_ref(def_id.expect_local(), hir_id);
                 }
                 Res::Err => {}
-                _ => todo!("TODO: Error on invalid param res"),
+                _ => {
+                    // This is handled in resolve
+                    self.tcx.dcx().delayed_bug(format!("parameter should have been resolved"));
+                }
             },
         }
     }

compiler/rustc_hir_analysis/src/errors.rs

@@ -10,6 +10,9 @@ use rustc_span::{symbol::Ident, Span, Symbol};
 mod pattern_types;
 pub use pattern_types::*;
 
+mod precise_captures;
+pub(crate) use precise_captures::*;
+
 #[derive(Diagnostic)]
 #[diag(hir_analysis_ambiguous_assoc_item)]
 pub struct AmbiguousAssocItem<'a> {

compiler/rustc_hir_analysis/src/errors/precise_captures.rs

@@ -0,0 +1,33 @@
+use rustc_macros::Diagnostic;
+use rustc_span::Span;
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_param_not_captured)]
+#[note]
+pub struct ParamNotCaptured {
+    #[primary_span]
+    pub param_span: Span,
+    #[label]
+    pub opaque_span: Span,
+    pub kind: &'static str,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_lifetime_not_captured)]
+pub struct LifetimeNotCaptured {
+    #[primary_span]
+    pub use_span: Span,
+    #[label(hir_analysis_param_label)]
+    pub param_span: Option<Span>,
+    #[label]
+    pub opaque_span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(hir_analysis_bad_precise_capture)]
+pub struct BadPreciseCapture {
+    #[primary_span]
+    pub span: Span,
+    pub kind: &'static str,
+    pub found: String,
+}