fix handling of Self
This commit is contained in:
Ariel Ben-Yehuda
parent
ad9986605f
commit
706e52e2cc
5 changed files with 79 additions and 26 deletions
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@ -794,7 +794,8 @@ impl<'a, 'gcx, 'tcx> InferCtxt<'a, 'gcx, 'tcx> {
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let generics = self.tcx.generics_of(did);
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// Account for the case where `did` corresponds to `Self`, which doesn't have
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// the expected type argument.
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if let Some(type_param) = generics.type_param(param, self.tcx) {
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if !param.is_self() {
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let type_param = generics.type_param(param, self.tcx);
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let hir = &self.tcx.hir;
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hir.as_local_node_id(type_param.def_id).map(|id| {
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// Get the `hir::TyParam` to verify wether it already has any bounds.
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@ -713,6 +713,13 @@ impl ty::EarlyBoundRegion {
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/// Information about the formal type/lifetime parameters associated
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/// with an item or method. Analogous to hir::Generics.
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///
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/// Note that in the presence of a `Self` parameter, the ordering here
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/// is different from the ordering in a Substs. Substs are ordered as
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/// Self, *Regions, *Other Type Params, (...child generics)
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/// while this struct is ordered as
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/// regions = Regions
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/// types = [Self, *Other Type Params]
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#[derive(Clone, Debug, RustcEncodable, RustcDecodable)]
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pub struct Generics {
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pub parent: Option<DefId>,
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@ -755,18 +762,34 @@ impl<'a, 'gcx, 'tcx> Generics {
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}
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}
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/// Returns the `TypeParameterDef` associated with this `ParamTy`, or `None`
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/// if `param` is `self`.
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/// Returns the `TypeParameterDef` associated with this `ParamTy`.
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pub fn type_param(&'tcx self,
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param: &ParamTy,
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tcx: TyCtxt<'a, 'gcx, 'tcx>)
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-> Option<&TypeParameterDef> {
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-> &TypeParameterDef {
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if let Some(idx) = param.idx.checked_sub(self.parent_count() as u32) {
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let type_param_start = (self.has_self as usize) + self.regions.len();
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if let Some(idx) = (idx as usize).checked_sub(type_param_start) {
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Some(&self.types[idx])
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// non-Self type parameters are always offset by exactly
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// `self.regions.len()`. In the absence of a Self, this is obvious,
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// but even in the absence of a `Self` we just have to "compensate"
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// for the regions:
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//
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// For example, for `trait Foo<'a, 'b, T1, T2>`, the
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// situation is:
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// Substs:
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// 0 1 2 3 4
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// Self 'a 'b T1 T2
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// generics.types:
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// 0 1 2
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// Self T1 T2
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// And it can be seen that to move from a substs offset to a
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// generics offset you just have to offset by the number of regions.
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let type_param_offset = self.regions.len();
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if let Some(idx) = (idx as usize).checked_sub(type_param_offset) {
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assert!(!(self.has_self && idx == 0));
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&self.types[idx]
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} else {
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None
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assert!(self.has_self && idx == 0);
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&self.types[0]
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}
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} else {
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tcx.generics_of(self.parent.expect("parent_count>0 but no parent?"))
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@ -519,9 +519,7 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
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} else if let Some(&ty::TyS {
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sty: ty::TypeVariants::TyParam(ref pt), ..
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}) = k.as_type() {
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!impl_generics.type_param(pt, self)
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.expect("drop impl param doesn't have a ParameterDef?")
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.pure_wrt_drop
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!impl_generics.type_param(pt, self).pure_wrt_drop
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} else {
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// not a type or region param - this should be reported
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// as an error.
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@ -28,7 +28,11 @@ struct Foo<T> {
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foo: &'static T
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}
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trait X<T> {}
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trait X<K>: Sized {
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fn foo<'a, L: X<&'a Nested<K>>>();
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// check that we give a sane error for `Self`
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fn bar<'a, L: X<&'a Nested<Self>>>();
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}
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struct Nested<K>(K);
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impl<K> Nested<K> {
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@ -27,37 +27,64 @@ note: ...so that the reference type `&'static T` does not outlive the data it po
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| ^^^^^^^^^^^^^^^
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error[E0309]: the parameter type `K` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:35:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:32:5
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34 | impl<K> Nested<K> {
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31 | trait X<K>: Sized {
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| - help: consider adding an explicit lifetime bound `K: 'a`...
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32 | fn foo<'a, L: X<&'a Nested<K>>>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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note: ...so that the reference type `&'a Nested<K>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:32:5
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32 | fn foo<'a, L: X<&'a Nested<K>>>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error[E0309]: the parameter type `Self` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:34:5
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34 | fn bar<'a, L: X<&'a Nested<Self>>>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= help: consider adding an explicit lifetime bound `Self: 'a`...
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note: ...so that the reference type `&'a Nested<Self>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:34:5
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34 | fn bar<'a, L: X<&'a Nested<Self>>>();
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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error[E0309]: the parameter type `K` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:39:5
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38 | impl<K> Nested<K> {
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| - help: consider adding an explicit lifetime bound `K: 'a`...
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35 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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36 | | }
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39 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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40 | | }
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| |_____^
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note: ...so that the reference type `&'a Nested<K>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:35:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:39:5
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35 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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36 | | }
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39 | / fn generic_in_parent<'a, L: X<&'a Nested<K>>>() {
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40 | | }
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| |_____^
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error[E0309]: the parameter type `M` may not live long enough
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--> $DIR/lifetime-doesnt-live-long-enough.rs:37:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:41:5
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37 | fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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41 | fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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| ^ -- help: consider adding an explicit lifetime bound `M: 'a`...
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| _____|
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| |
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38 | | }
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42 | | }
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| |_____^
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note: ...so that the reference type `&'a Nested<M>` does not outlive the data it points at
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--> $DIR/lifetime-doesnt-live-long-enough.rs:37:5
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--> $DIR/lifetime-doesnt-live-long-enough.rs:41:5
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37 | / fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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38 | | }
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41 | / fn generic_in_child<'a, 'b, L: X<&'a Nested<M>>, M: 'b>() {
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42 | | }
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| |_____^
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error: aborting due to 4 previous errors
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error: aborting due to 6 previous errors
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