diff --git a/src/librustc_lint/builtin.rs b/src/librustc_lint/builtin.rs
index c6698cbd006..bdb36ab15b6 100644
--- a/src/librustc_lint/builtin.rs
+++ b/src/librustc_lint/builtin.rs
@@ -1316,24 +1316,25 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnreachablePub {
     }
 }
 
-/// Lint for trait and lifetime bounds that are (accidentally) accepted by the parser, but
-/// ignored later.
+/// Lint for trait and lifetime bounds in type aliases being mostly ignored:
+/// They are relevant when using associated types, but otherwise neither checked
+/// at definition site nor enforced at use site.
 
-pub struct IgnoredGenericBounds;
+pub struct TypeAliasBounds;
 
 declare_lint! {
-    IGNORED_GENERIC_BOUNDS,
+    TYPE_ALIAS_BOUNDS,
     Warn,
-    "these generic bounds are ignored"
+    "bounds in type aliases are not enforced"
 }
 
-impl LintPass for IgnoredGenericBounds {
+impl LintPass for TypeAliasBounds {
     fn get_lints(&self) -> LintArray {
-        lint_array!(IGNORED_GENERIC_BOUNDS)
+        lint_array!(TYPE_ALIAS_BOUNDS)
     }
 }
 
-impl EarlyLintPass for IgnoredGenericBounds {
+impl EarlyLintPass for TypeAliasBounds {
     fn check_item(&mut self, cx: &EarlyContext, item: &ast::Item) {
         let type_alias_generics = match item.node {
             ast::ItemKind::Ty(_, ref generics) => generics,
@@ -1343,8 +1344,8 @@ impl EarlyLintPass for IgnoredGenericBounds {
         if !type_alias_generics.where_clause.predicates.is_empty() {
             let spans : Vec<_> = type_alias_generics.where_clause.predicates.iter()
                 .map(|pred| pred.span()).collect();
-            cx.span_lint(IGNORED_GENERIC_BOUNDS, spans,
-                "where clauses are ignored in type aliases");
+            cx.span_lint(TYPE_ALIAS_BOUNDS, spans,
+                "where clauses are not enforced in type aliases");
         }
         // The parameters must not have bounds
         for param in type_alias_generics.params.iter() {
@@ -1354,9 +1355,9 @@ impl EarlyLintPass for IgnoredGenericBounds {
             };
             if !spans.is_empty() {
                 cx.span_lint(
-                    IGNORED_GENERIC_BOUNDS,
+                    TYPE_ALIAS_BOUNDS,
                     spans,
-                    "bounds on generic parameters are ignored in type aliases",
+                    "bounds on generic parameters are not enforced in type aliases",
                 );
             }
         }
diff --git a/src/librustc_lint/lib.rs b/src/librustc_lint/lib.rs
index 779aa3a9037..38f7a0b6faa 100644
--- a/src/librustc_lint/lib.rs
+++ b/src/librustc_lint/lib.rs
@@ -109,7 +109,7 @@ pub fn register_builtins(store: &mut lint::LintStore, sess: Option<&Session>) {
                        UnusedImportBraces,
                        AnonymousParameters,
                        UnusedDocComment,
-                       IgnoredGenericBounds,
+                       TypeAliasBounds,
                        );
 
     add_early_builtin_with_new!(sess,
diff --git a/src/test/compile-fail/issue-17994.rs b/src/test/compile-fail/issue-17994.rs
index 0f30e2461cf..7c3811e2ef2 100644
--- a/src/test/compile-fail/issue-17994.rs
+++ b/src/test/compile-fail/issue-17994.rs
@@ -10,5 +10,5 @@
 
 trait Tr {}
 type Huh<T> where T: Tr = isize; //~  ERROR type parameter `T` is unused
-                                 //~| WARNING where clauses are ignored in type aliases
+                                 //~| WARNING where clauses are not enforced in type aliases
 fn main() {}
diff --git a/src/test/compile-fail/private-in-public-warn.rs b/src/test/compile-fail/private-in-public-warn.rs
index cc9eed7e654..8bd9b0a901d 100644
--- a/src/test/compile-fail/private-in-public-warn.rs
+++ b/src/test/compile-fail/private-in-public-warn.rs
@@ -58,7 +58,7 @@ mod traits {
     pub trait PubTr {}
 
     pub type Alias<T: PrivTr> = T; //~ ERROR private trait `traits::PrivTr` in public interface
-    //~^ WARNING bounds on generic parameters are ignored
+    //~^ WARNING bounds on generic parameters are not enforced in type aliases
     //~| WARNING hard error
     pub trait Tr1: PrivTr {} //~ ERROR private trait `traits::PrivTr` in public interface
     //~^ WARNING hard error
@@ -85,7 +85,7 @@ mod traits_where {
     pub type Alias<T> where T: PrivTr = T;
         //~^ ERROR private trait `traits_where::PrivTr` in public interface
         //~| WARNING hard error
-        //~| WARNING where clauses are ignored in type aliases
+        //~| WARNING where clauses are not enforced in type aliases
     pub trait Tr2<T> where T: PrivTr {}
         //~^ ERROR private trait `traits_where::PrivTr` in public interface
         //~| WARNING hard error
diff --git a/src/test/ui/type-alias-bounds.rs b/src/test/ui/type-alias-bounds.rs
index ed368e8f150..7ec3afd9c87 100644
--- a/src/test/ui/type-alias-bounds.rs
+++ b/src/test/ui/type-alias-bounds.rs
@@ -10,21 +10,20 @@
 
 // Test ignored_generic_bounds lint warning about bounds in type aliases
 
-// must-compile-successfully
 #![allow(dead_code)]
 
 use std::rc::Rc;
 
 type SVec<T: Send+Send> = Vec<T>;
-//~^ WARN bounds on generic parameters are ignored in type aliases
+//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
 type S2Vec<T> where T: Send = Vec<T>;
-//~^ WARN where clauses are ignored in type aliases
+//~^ WARN where clauses are not enforced in type aliases [type_alias_bounds]
 type VVec<'b, 'a: 'b+'b> = (&'b u32, Vec<&'a i32>);
-//~^ WARN bounds on generic parameters are ignored in type aliases
+//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
 type WVec<'b, T: 'b+'b> = (&'b u32, Vec<T>);
-//~^ WARN bounds on generic parameters are ignored in type aliases
+//~^ WARN bounds on generic parameters are not enforced in type aliases [type_alias_bounds]
 type W2Vec<'b, T> where T: 'b, T: 'b = (&'b u32, Vec<T>);
-//~^ WARN where clauses are ignored in type aliases
+//~^ WARN where clauses are not enforced in type aliases [type_alias_bounds]
 
 static STATIC : u32 = 0;
 
@@ -48,4 +47,18 @@ fn foo<'a>(y: &'a i32) {
     x.1.push(y); // &'a i32: 'static does not hold
 }
 
+// Bounds are not checked either, i.e. the definition is not necessarily well-formed
+struct Sendable<T: Send>(T);
+type MySendable<T> = Sendable<T>; // no error here!
+
+// However, bounds *are* taken into account when accessing associated types
+trait Bound { type Assoc; }
+type T1<U: Bound> = U::Assoc;
+//~^ WARN bounds on generic parameters are not enforced in type aliases
+type T2<U> where U: Bound = U::Assoc;
+//~^ WARN where clauses are not enforced in type aliases
+type T3<U> = U::Assoc;
+//~^ ERROR associated type `Assoc` not found for `U`
+type T4<U> = <U as Bound>::Assoc;
+
 fn main() {}
diff --git a/src/test/ui/type-alias-bounds.stderr b/src/test/ui/type-alias-bounds.stderr
index 5237f3c19ef..46aacd7321c 100644
--- a/src/test/ui/type-alias-bounds.stderr
+++ b/src/test/ui/type-alias-bounds.stderr
@@ -1,32 +1,53 @@
-warning: bounds on generic parameters are ignored in type aliases
-  --> $DIR/type-alias-bounds.rs:18:14
+warning: bounds on generic parameters are not enforced in type aliases
+  --> $DIR/type-alias-bounds.rs:17:14
    |
 LL | type SVec<T: Send+Send> = Vec<T>;
    |              ^^^^ ^^^^
    |
-   = note: #[warn(ignored_generic_bounds)] on by default
+   = note: #[warn(type_alias_bounds)] on by default
 
-warning: where clauses are ignored in type aliases
-  --> $DIR/type-alias-bounds.rs:20:21
+warning: where clauses are not enforced in type aliases
+  --> $DIR/type-alias-bounds.rs:19:21
    |
 LL | type S2Vec<T> where T: Send = Vec<T>;
    |                     ^^^^^^^
 
-warning: bounds on generic parameters are ignored in type aliases
-  --> $DIR/type-alias-bounds.rs:22:19
+warning: bounds on generic parameters are not enforced in type aliases
+  --> $DIR/type-alias-bounds.rs:21:19
    |
 LL | type VVec<'b, 'a: 'b+'b> = (&'b u32, Vec<&'a i32>);
    |                   ^^ ^^
 
-warning: bounds on generic parameters are ignored in type aliases
-  --> $DIR/type-alias-bounds.rs:24:18
+warning: bounds on generic parameters are not enforced in type aliases
+  --> $DIR/type-alias-bounds.rs:23:18
    |
 LL | type WVec<'b, T: 'b+'b> = (&'b u32, Vec<T>);
    |                  ^^ ^^
 
-warning: where clauses are ignored in type aliases
-  --> $DIR/type-alias-bounds.rs:26:25
+warning: where clauses are not enforced in type aliases
+  --> $DIR/type-alias-bounds.rs:25:25
    |
 LL | type W2Vec<'b, T> where T: 'b, T: 'b = (&'b u32, Vec<T>);
    |                         ^^^^^  ^^^^^
 
+warning: bounds on generic parameters are not enforced in type aliases
+  --> $DIR/type-alias-bounds.rs:56:12
+   |
+LL | type T1<U: Bound> = U::Assoc;
+   |            ^^^^^
+
+warning: where clauses are not enforced in type aliases
+  --> $DIR/type-alias-bounds.rs:58:18
+   |
+LL | type T2<U> where U: Bound = U::Assoc;
+   |                  ^^^^^^^^
+
+error[E0220]: associated type `Assoc` not found for `U`
+  --> $DIR/type-alias-bounds.rs:60:14
+   |
+LL | type T3<U> = U::Assoc;
+   |              ^^^^^^^^ associated type `Assoc` not found
+
+error: aborting due to previous error
+
+If you want more information on this error, try using "rustc --explain E0220"