Remove "static item recursion checking" in favor of relying on cycle checks in the query engine

Author: Zoxc

src/librustc_driver/driver.rs

@@ -36,7 +36,7 @@ use rustc_typeck as typeck;
 use rustc_privacy;
 use rustc_plugin::registry::Registry;
 use rustc_plugin as plugin;
-use rustc_passes::{self, ast_validation, loops, consts, static_recursion, hir_stats};
+use rustc_passes::{self, ast_validation, loops, consts, hir_stats};
 use rustc_const_eval::{self, check_match};
 use super::Compilation;
 
@@ -972,10 +972,6 @@ pub fn phase_3_run_analysis_passes<'tcx, F, R>(trans: &TransCrate,
          "loop checking",
          || loops::check_crate(sess, &hir_map));
 
-    time(time_passes,
-              "static item recursion checking",
-              || static_recursion::check_crate(sess, &hir_map))?;
-
     let mut local_providers = ty::maps::Providers::default();
     default_provide(&mut local_providers);
     trans.provide(&mut local_providers);

src/librustc_passes/diagnostics.rs

@@ -128,22 +128,6 @@ impl !Enterprise for Foo { }
 Please note that negative impls are only allowed for auto traits.
 "##,
 
-E0265: r##"
-This error indicates that a static or constant references itself.
-All statics and constants need to resolve to a value in an acyclic manner.
-
-For example, neither of the following can be sensibly compiled:
-
-```compile_fail,E0265
-const X: u32 = X;
-```
-
-```compile_fail,E0265
-const X: u32 = Y;
-const Y: u32 = X;
-```
-"##,
-
 E0267: r##"
 This error indicates the use of a loop keyword (`break` or `continue`) inside a
 closure but outside of any loop. Erroneous code example:

src/librustc_passes/lib.rs

@@ -42,7 +42,6 @@ pub mod consts;
 pub mod hir_stats;
 pub mod loops;
 mod mir_stats;
-pub mod static_recursion;
 
 #[cfg(not(stage0))] // remove after the next snapshot
 __build_diagnostic_array! { librustc_passes, DIAGNOSTICS }

src/librustc_passes/static_recursion.rs

@@ -8,12 +8,12 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-const FOO: usize = FOO; //~ ERROR recursive constant
+const FOO: usize = FOO; //~ ERROR E0391
 
 fn main() {
     let _x: [u8; FOO]; // caused stack overflow prior to fix
     let _y: usize = 1 + {
-        const BAR: usize = BAR; //~ ERROR recursive constant
+        const BAR: usize = BAR;
         let _z: [u8; BAR]; // caused stack overflow prior to fix
         1
     };

src/test/compile-fail/issue-17252.rs

@@ -11,18 +11,7 @@
 // Check that an enum with recursion in the discriminant throws
 // the appropriate error (rather than, say, blowing the stack).
 enum X {
-    A = X::A as isize, //~ ERROR E0265
+    A = X::A as isize, //~ ERROR E0391
 }
 
-// Since `Y::B` here defaults to `Y::A+1`, this is also a
-// recursive definition.
-enum Y {
-    A = Y::B as isize, //~ ERROR E0265
-    B,
-}
-
-const A: i32 = B; //~ ERROR E0265
-
-const B: i32 = A; //~ ERROR E0265
-
 fn main() { }

src/test/ui/issue-23302.rs renamed to src/test/ui/issue-23302-1.rs

@@ -0,0 +1,15 @@
+error[E0391]: unsupported cyclic reference between types/traits detected
+  --> $DIR/issue-23302-1.rs:14:9
+   |
+14 |     A = X::A as isize, //~ ERROR E0391
+   |         ^^^^^^^^^^^^^ cyclic reference
+   |
+note: the cycle begins when const-evaluating `X::A::{{initializer}}`...
+  --> $DIR/issue-23302-1.rs:14:5
+   |
+14 |     A = X::A as isize, //~ ERROR E0391
+   |     ^^^^^^^^^^^^^^^^^
+   = note: ...which then again requires const-evaluating `X::A::{{initializer}}`, completing the cycle.
+
+error: aborting due to previous error
+