6 files changed, 76 insertions, 19 deletions

diff --git a/crates/ra_hir_def/src/body/lower.rs b/crates/ra_hir_def/src/body/lower.rs
index 6caa87db4..79abe55ce 100644
--- a/crates/ra_hir_def/src/body/lower.rs
+++ b/crates/ra_hir_def/src/body/lower.rs
@@ -33,6 +33,7 @@ use crate::{
 };
 
 use super::{ExprSource, PatSource};
+use ast::AstChildren;
 
 pub(super) fn lower(
     db: &dyn DefDatabase,
@@ -598,8 +599,8 @@ impl ExprCollector<'_> {
             }
             ast::Pat::TupleStructPat(p) => {
                 let path = p.path().and_then(|path| self.expander.parse_path(path));
-                let args = p.args().map(|p| self.collect_pat(p)).collect();
-                Pat::TupleStruct { path, args }
+                let (args, ellipsis) = self.collect_tuple_pat(p.args());
+                Pat::TupleStruct { path, args, ellipsis }
             }
             ast::Pat::RefPat(p) => {
                 let pat = self.collect_pat_opt(p.pat());
@@ -616,10 +617,10 @@ impl ExprCollector<'_> {
             }
             ast::Pat::ParenPat(p) => return self.collect_pat_opt(p.pat()),
             ast::Pat::TuplePat(p) => {
-                let args = p.args().map(|p| self.collect_pat(p)).collect();
-                Pat::Tuple(args)
+                let (args, ellipsis) = self.collect_tuple_pat(p.args());
+                Pat::Tuple { args, ellipsis }
             }
-            ast::Pat::PlaceholderPat(_) | ast::Pat::DotDotPat(_) => Pat::Wild,
+            ast::Pat::PlaceholderPat(_) => Pat::Wild,
             ast::Pat::RecordPat(p) => {
                 let path = p.path().and_then(|path| self.expander.parse_path(path));
                 let record_field_pat_list =
@@ -665,6 +666,9 @@ impl ExprCollector<'_> {
                     Pat::Missing
                 }
             }
+            ast::Pat::DotDotPat(_) => unreachable!(
+                "`DotDotPat` requires special handling and should not be mapped to a Pat."
+            ),
             // FIXME: implement
             ast::Pat::BoxPat(_) | ast::Pat::RangePat(_) | ast::Pat::MacroPat(_) => Pat::Missing,
         };
@@ -679,6 +683,19 @@ impl ExprCollector<'_> {
             self.missing_pat()
         }
     }
+
+    fn collect_tuple_pat(&mut self, args: AstChildren<ast::Pat>) -> (Vec<PatId>, Option<usize>) {
+        // Find the location of the `..`, if there is one. Note that we do not
+        // consider the possiblity of there being multiple `..` here.
+        let ellipsis = args.clone().position(|p| matches!(p, ast::Pat::DotDotPat(_)));
+        // We want to skip the `..` pattern here, since we account for it above.
+        let args = args
+            .filter(|p| !matches!(p, ast::Pat::DotDotPat(_)))
+            .map(|p| self.collect_pat(p))
+            .collect();
+
+        (args, ellipsis)
+    }
 }
 
 impl From<ast::BinOp> for BinaryOp {
diff --git a/crates/ra_hir_def/src/data.rs b/crates/ra_hir_def/src/data.rs
index 56a20c5bd..b3c91fea2 100644
--- a/crates/ra_hir_def/src/data.rs
+++ b/crates/ra_hir_def/src/data.rs
@@ -15,7 +15,7 @@ use ra_syntax::ast::{
 use crate::{
     attr::Attrs,
     db::DefDatabase,
-    path::{path, GenericArgs, Path},
+    path::{path, AssociatedTypeBinding, GenericArgs, Path},
     src::HasSource,
     type_ref::{Mutability, TypeBound, TypeRef},
     visibility::RawVisibility,
@@ -95,7 +95,11 @@ fn desugar_future_path(orig: TypeRef) -> Path {
     let path = path![std::future::Future];
     let mut generic_args: Vec<_> = std::iter::repeat(None).take(path.segments.len() - 1).collect();
     let mut last = GenericArgs::empty();
-    last.bindings.push((name![Output], orig));
+    last.bindings.push(AssociatedTypeBinding {
+        name: name![Output],
+        type_ref: Some(orig),
+        bounds: Vec::new(),
+    });
     generic_args.push(Some(Arc::new(last)));
 
     Path::from_known_path(path, generic_args)
diff --git a/crates/ra_hir_def/src/expr.rs b/crates/ra_hir_def/src/expr.rs
index e11bdf3ec..a0cdad529 100644
--- a/crates/ra_hir_def/src/expr.rs
+++ b/crates/ra_hir_def/src/expr.rs
@@ -374,7 +374,7 @@ pub struct RecordFieldPat {
 pub enum Pat {
     Missing,
     Wild,
-    Tuple(Vec<PatId>),
+    Tuple { args: Vec<PatId>, ellipsis: Option<usize> },
     Or(Vec<PatId>),
     Record { path: Option<Path>, args: Vec<RecordFieldPat>, ellipsis: bool },
     Range { start: ExprId, end: ExprId },
@@ -382,7 +382,7 @@ pub enum Pat {
     Path(Path),
     Lit(ExprId),
     Bind { mode: BindingAnnotation, name: Name, subpat: Option<PatId> },
-    TupleStruct { path: Option<Path>, args: Vec<PatId> },
+    TupleStruct { path: Option<Path>, args: Vec<PatId>, ellipsis: Option<usize> },
     Ref { pat: PatId, mutability: Mutability },
 }
 
@@ -393,7 +393,7 @@ impl Pat {
             Pat::Bind { subpat, .. } => {
                 subpat.iter().copied().for_each(f);
             }
-            Pat::Or(args) | Pat::Tuple(args) | Pat::TupleStruct { args, .. } => {
+            Pat::Or(args) | Pat::Tuple { args, .. } | Pat::TupleStruct { args, .. } => {
                 args.iter().copied().for_each(f);
             }
             Pat::Ref { pat, .. } => f(*pat),
diff --git a/crates/ra_hir_def/src/path.rs b/crates/ra_hir_def/src/path.rs
index 91c7b3e09..162b3c8c7 100644
--- a/crates/ra_hir_def/src/path.rs
+++ b/crates/ra_hir_def/src/path.rs
@@ -14,7 +14,10 @@ use hir_expand::{
 use ra_db::CrateId;
 use ra_syntax::ast;
 
-use crate::{type_ref::TypeRef, InFile};
+use crate::{
+    type_ref::{TypeBound, TypeRef},
+    InFile,
+};
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub struct ModPath {
@@ -111,7 +114,21 @@ pub struct GenericArgs {
     /// is left out.
     pub has_self_type: bool,
     /// Associated type bindings like in `Iterator<Item = T>`.
-    pub bindings: Vec<(Name, TypeRef)>,
+    pub bindings: Vec<AssociatedTypeBinding>,
+}
+
+/// An associated type binding like in `Iterator<Item = T>`.
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+pub struct AssociatedTypeBinding {
+    /// The name of the associated type.
+    pub name: Name,
+    /// The type bound to this associated type (in `Item = T`, this would be the
+    /// `T`). This can be `None` if there are bounds instead.
+    pub type_ref: Option<TypeRef>,
+    /// Bounds for the associated type, like in `Iterator<Item:
+    /// SomeOtherTrait>`. (This is the unstable `associated_type_bounds`
+    /// feature.)
+    pub bounds: Vec<TypeBound>,
 }
 
 /// A single generic argument.
diff --git a/crates/ra_hir_def/src/path/lower.rs b/crates/ra_hir_def/src/path/lower.rs
index 0f806d6fb..9ec2e0dcd 100644
--- a/crates/ra_hir_def/src/path/lower.rs
+++ b/crates/ra_hir_def/src/path/lower.rs
@@ -9,11 +9,12 @@ use hir_expand::{
     hygiene::Hygiene,
     name::{name, AsName},
 };
-use ra_syntax::ast::{self, AstNode, TypeAscriptionOwner};
+use ra_syntax::ast::{self, AstNode, TypeAscriptionOwner, TypeBoundsOwner};
 
+use super::AssociatedTypeBinding;
 use crate::{
     path::{GenericArg, GenericArgs, ModPath, Path, PathKind},
-    type_ref::TypeRef,
+    type_ref::{TypeBound, TypeRef},
 };
 
 pub(super) use lower_use::lower_use_tree;
@@ -136,10 +137,16 @@ pub(super) fn lower_generic_args(node: ast::TypeArgList) -> Option<GenericArgs>
     // lifetimes ignored for now
     let mut bindings = Vec::new();
     for assoc_type_arg in node.assoc_type_args() {
+        let assoc_type_arg: ast::AssocTypeArg = assoc_type_arg;
         if let Some(name_ref) = assoc_type_arg.name_ref() {
             let name = name_ref.as_name();
-            let type_ref = TypeRef::from_ast_opt(assoc_type_arg.type_ref());
-            bindings.push((name, type_ref));
+            let type_ref = assoc_type_arg.type_ref().map(TypeRef::from_ast);
+            let bounds = if let Some(l) = assoc_type_arg.type_bound_list() {
+                l.bounds().map(TypeBound::from_ast).collect()
+            } else {
+                Vec::new()
+            };
+            bindings.push(AssociatedTypeBinding { name, type_ref, bounds });
         }
     }
     if args.is_empty() && bindings.is_empty() {
@@ -168,7 +175,11 @@ fn lower_generic_args_from_fn_path(
     }
     if let Some(ret_type) = ret_type {
         let type_ref = TypeRef::from_ast_opt(ret_type.type_ref());
-        bindings.push((name![Output], type_ref))
+        bindings.push(AssociatedTypeBinding {
+            name: name![Output],
+            type_ref: Some(type_ref),
+            bounds: Vec::new(),
+        });
     }
     if args.is_empty() && bindings.is_empty() {
         None
diff --git a/crates/ra_hir_def/src/type_ref.rs b/crates/ra_hir_def/src/type_ref.rs
index ea29c4176..f308c6bdf 100644
--- a/crates/ra_hir_def/src/type_ref.rs
+++ b/crates/ra_hir_def/src/type_ref.rs
@@ -163,8 +163,16 @@ impl TypeRef {
                         let crate::path::GenericArg::Type(type_ref) = arg;
                         go(type_ref, f);
                     }
-                    for (_, type_ref) in &args_and_bindings.bindings {
-                        go(type_ref, f);
+                    for binding in &args_and_bindings.bindings {
+                        if let Some(type_ref) = &binding.type_ref {
+                            go(type_ref, f);
+                        }
+                        for bound in &binding.bounds {
+                            match bound {
+                                TypeBound::Path(path) => go_path(path, f),
+                                TypeBound::Error => (),
+                            }
+                        }
                     }
                 }
             }