Added proper explanation of ErrorCode-E0688

1 files changed, 36 insertions, 0 deletions

diff --git a/src/librustc_error_codes/error_codes/E0688.md b/src/librustc_error_codes/error_codes/E0688.md
new file mode 100644
index 00000000000..db50f490208
--- /dev/null
+++ b/src/librustc_error_codes/error_codes/E0688.md
@@ -0,0 +1,36 @@
+In-band lifetimes were mixed with explicit lifetime binders.
+
+Erroneous code example:
+
+```compile_fail,E0688
+#![feature(in_band_lifetimes)]
+
+fn foo<'a>(x: &'a u32, y: &'b u32) {}   // error!
+
+struct Foo<'a> { x: &'a u32 }
+
+impl Foo<'a> {
+    fn bar<'b>(x: &'a u32, y: &'b u32, z: &'c u32) {}   // error!
+}
+
+impl<'b> Foo<'a> {  // error!
+    fn baz() {}
+}
+```
+
+In-band lifetimes cannot be mixed with explicit lifetime binders.
+For example:
+
+```
+fn foo<'a, 'b>(x: &'a u32, y: &'b u32) {}   // ok!
+
+struct Foo<'a> { x: &'a u32 }
+
+impl<'a> Foo<'a> {
+    fn bar<'b,'c>(x: &'a u32, y: &'b u32, z: &'c u32) {}    // ok!
+}
+
+impl<'a> Foo<'a> {  // ok!
+    fn baz() {}
+}
+```