Improve invalid recursive types diagnostic

Author: nagisa

src/librustc_typeck/check/mod.rs

@@ -4273,10 +4273,8 @@ pub fn check_representable(tcx: &ty::ctxt,
     // caught by case 1.
     match rty.is_representable(tcx, sp) {
       ty::SelfRecursive => {
-        span_err!(tcx.sess, sp, E0072,
-            "illegal recursive {} type; \
-             wrap the inner value in a box to make it representable",
-            designation);
+        span_err!(tcx.sess, sp, E0072, "invalid recursive {} type", designation);
+        tcx.sess.fileline_help(sp, "wrap the inner value in a box to make it representable");
         return false
       }
       ty::Representable | ty::ContainsRecursive => (),

src/librustc_typeck/diagnostics.rs

@@ -778,7 +778,7 @@ the pointer the size of the type would need to be unbounded.
 Consider the following erroneous definition of a type for a list of bytes:
 
 ```
-// error, illegal recursive struct type
+// error, invalid recursive struct type
 struct ListNode {
     head: u8,
     tail: Option<ListNode>,
@@ -2345,7 +2345,7 @@ register_diagnostics! {
     E0241,
     E0242, // internal error looking up a definition
     E0245, // not a trait
-    E0246, // illegal recursive type
+    E0246, // invalid recursive type
     E0247, // found module name used as a type
     E0248, // found value name used as a type
     E0319, // trait impls for defaulted traits allowed just for structs/enums

src/test/compile-fail/infinite-tag-type-recursion.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 
-// error-pattern: illegal recursive enum type; wrap the inner value in a box
+// error-pattern: invalid recursive enum type
 
 enum mlist { cons(isize, mlist), nil, }
 

src/test/compile-fail/issue-17431-1.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 struct Foo { foo: Option<Option<Foo>> }
-//~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive struct type
 
 impl Foo { fn bar(&self) {} }
 

src/test/compile-fail/issue-17431-2.rs

@@ -9,10 +9,10 @@
 // except according to those terms.
 
 struct Baz { q: Option<Foo> }
-//~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive struct type
 
 struct Foo { q: Option<Baz> }
-//~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive struct type
 
 impl Foo { fn bar(&self) {} }
 

src/test/compile-fail/issue-17431-3.rs

@@ -11,7 +11,7 @@
 use std::sync::Mutex;
 
 struct Foo { foo: Mutex<Option<Foo>> }
-//~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive struct type
 
 impl Foo { fn bar(&self) {} }
 

src/test/compile-fail/issue-17431-4.rs

@@ -11,7 +11,7 @@
 use std::marker;
 
 struct Foo<T> { foo: Option<Option<Foo<T>>>, marker: marker::PhantomData<T> }
-//~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive struct type
 
 impl<T> Foo<T> { fn bar(&self) {} }
 

src/test/compile-fail/issue-17431-5.rs

@@ -12,7 +12,7 @@ use std::marker;
 
 struct Foo { foo: Bar<Foo> }
 struct Bar<T> { x: Bar<Foo> , marker: marker::PhantomData<T> }
-//~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive struct type
 
 impl Foo { fn foo(&self) {} }
 

src/test/compile-fail/issue-17431-6.rs

@@ -11,7 +11,7 @@
 use std::sync::Mutex;
 
 enum Foo { X(Mutex<Option<Foo>>) }
-//~^ ERROR illegal recursive enum type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive enum type
 
 impl Foo { fn bar(self) {} }
 

src/test/compile-fail/issue-17431-7.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 enum Foo { Voo(Option<Option<Foo>>) }
-//~^ ERROR illegal recursive enum type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive enum type
 
 impl Foo { fn bar(&self) {} }
 

src/test/compile-fail/issue-2718-a.rs

@@ -16,7 +16,7 @@ mod pingpong {
     use send_packet;
     pub type ping = send_packet<pong>;
     pub struct pong(send_packet<ping>);
-    //~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+    //~^ ERROR invalid recursive struct type
 }
 
 fn main() {}

src/test/compile-fail/issue-3008-1.rs

@@ -10,7 +10,7 @@
 
 enum foo { foo_(bar) }
 enum bar { bar_none, bar_some(bar) }
-//~^ ERROR illegal recursive enum type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive enum type
 
 fn main() {
 }

src/test/compile-fail/issue-3008-2.rs

@@ -12,7 +12,7 @@
 
 enum foo { foo_(bar) }
 struct bar { x: bar }
-//~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive struct type
 
 fn main() {
 }

src/test/compile-fail/issue-3008-3.rs

@@ -12,7 +12,7 @@ use std::marker;
 
 enum E1 { V1(E2<E1>), }
 enum E2<T> { V2(E2<E1>, marker::PhantomData<T>), }
-//~^ ERROR illegal recursive enum type; wrap the inner value in a box to make it representable
+//~^ ERROR invalid recursive enum type
 
 impl E1 { fn foo(&self) {} }
 

src/test/compile-fail/issue-3779.rs

@@ -9,7 +9,7 @@
 // except according to those terms.
 
 struct S {
-    //~^ ERROR illegal recursive struct type; wrap the inner value in a box to make it representable
+    //~^ ERROR invalid recursive struct type
     element: Option<S>
 }
 

src/test/compile-fail/recursive-enum.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern: illegal recursive enum type
+// error-pattern: invalid recursive enum type
 
 enum list<T> { cons(T, list<T>), nil }
 

src/test/compile-fail/type-recursive.rs

@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// error-pattern:illegal recursive struct type
+// error-pattern:invalid recursive struct type
 struct t1 {
     foo: isize,
     foolish: t1