Rollup merge of rust-lang#62450 - nagisa:reclimit, r=pnkfelix

Raise the default recursion limit to 128

The previous limit of 64 is being (just) barely hit by genuine code out there, which is causing issues like rust-lang#62059 to rear their end.

Ideally, we wouldn’t have such arbitrary limits at all, but while we do, it makes a lot of sense to just raise this limit whenever genuine use-cases end up hitting it.

r? @pnkfelix

Fixes rust-lang#62059

src/librustc/middle/recursion_limit.rs

@@ -12,7 +12,7 @@ use syntax::symbol::{Symbol, sym};
 use rustc_data_structures::sync::Once;
 
 pub fn update_limits(sess: &Session, krate: &ast::Crate) {
-    update_limit(krate, &sess.recursion_limit, sym::recursion_limit, 64);
+    update_limit(krate, &sess.recursion_limit, sym::recursion_limit, 128);
     update_limit(krate, &sess.type_length_limit, sym::type_length_limit, 1048576);
 }
 

src/test/rustdoc/deep-structures.rs

@@ -0,0 +1,104 @@
+// This test verifies that we do not hit recursion limit trying to prove auto-trait bounds for
+// reasonably deep structures.
+
+#![crate_type="rlib"]
+
+pub struct A01(A02);
+pub struct A02(A03);
+pub struct A03(A04);
+pub struct A04(A05);
+pub struct A05(A06);
+pub struct A06(A07);
+pub struct A07(A08);
+pub struct A08(A09);
+pub struct A09(A10);
+pub struct A10(A11);
+pub struct A11(A12);
+pub struct A12(A13);
+pub struct A13(A14);
+pub struct A14(A15);
+pub struct A15(A16);
+pub struct A16(A17);
+pub struct A17(A18);
+pub struct A18(A19);
+pub struct A19(A20);
+pub struct A20(A21);
+pub struct A21(A22);
+pub struct A22(A23);
+pub struct A23(A24);
+pub struct A24(A25);
+pub struct A25(A26);
+pub struct A26(A27);
+pub struct A27(A28);
+pub struct A28(A29);
+pub struct A29(A30);
+pub struct A30(A31);
+pub struct A31(A32);
+pub struct A32(A33);
+pub struct A33(A34);
+pub struct A34(A35);
+pub struct A35(A36);
+pub struct A36(A37);
+pub struct A37(A38);
+pub struct A38(A39);
+pub struct A39(A40);
+pub struct A40(A41);
+pub struct A41(A42);
+pub struct A42(A43);
+pub struct A43(A44);
+pub struct A44(A45);
+pub struct A45(A46);
+pub struct A46(A47);
+pub struct A47(A48);
+pub struct A48(A49);
+pub struct A49(A50);
+pub struct A50(A51);
+pub struct A51(A52);
+pub struct A52(A53);
+pub struct A53(A54);
+pub struct A54(A55);
+pub struct A55(A56);
+pub struct A56(A57);
+pub struct A57(A58);
+pub struct A58(A59);
+pub struct A59(A60);
+pub struct A60(A61);
+pub struct A61(A62);
+pub struct A62(A63);
+pub struct A63(A64);
+pub struct A64(A65);
+pub struct A65(A66);
+pub struct A66(A67);
+pub struct A67(A68);
+pub struct A68(A69);
+pub struct A69(A70);
+pub struct A70(A71);
+pub struct A71(A72);
+pub struct A72(A73);
+pub struct A73(A74);
+pub struct A74(A75);
+pub struct A75(A76);
+pub struct A76(A77);
+pub struct A77(A78);
+pub struct A78(A79);
+pub struct A79(A80);
+pub struct A80(A81);
+pub struct A81(A82);
+pub struct A82(A83);
+pub struct A83(A84);
+pub struct A84(A85);
+pub struct A85(A86);
+pub struct A86(A87);
+pub struct A87(A88);
+pub struct A88(A89);
+pub struct A89(A90);
+pub struct A90(A91);
+pub struct A91(A92);
+pub struct A92(A93);
+pub struct A93(A94);
+pub struct A94(A95);
+pub struct A95(A96);
+pub struct A96(A97);
+pub struct A97(A98);
+pub struct A98(A99);
+pub struct A99;

src/test/ui/dropck/dropck_no_diverge_on_nonregular_1.stderr

@@ -4,15 +4,15 @@ error[E0320]: overflow while adding drop-check rules for FingerTree<i32>
 LL |     let ft =
    |         ^^
    |
-   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 error[E0320]: overflow while adding drop-check rules for FingerTree<i32>
   --> $DIR/dropck_no_diverge_on_nonregular_1.rs:25:9
    |
 LL |         FingerTree::Single(1);
    |         ^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 error: aborting due to 2 previous errors
 

src/test/ui/dropck/dropck_no_diverge_on_nonregular_2.stderr

@@ -4,15 +4,15 @@ error[E0320]: overflow while adding drop-check rules for FingerTree<i32>
 LL |     let ft =
    |         ^^
    |
-   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 error[E0320]: overflow while adding drop-check rules for FingerTree<i32>
   --> $DIR/dropck_no_diverge_on_nonregular_2.rs:24:9
    |
 LL |         FingerTree::Single(1);
    |         ^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 error: aborting due to 2 previous errors
 

src/test/ui/dropck/dropck_no_diverge_on_nonregular_3.stderr

@@ -4,23 +4,23 @@ error[E0320]: overflow while adding drop-check rules for std::option::Option<Wra
 LL |     let w =
    |         ^
    |
-   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<u32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<u32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 error[E0320]: overflow while adding drop-check rules for std::option::Option<Wrapper<u32>>
   --> $DIR/dropck_no_diverge_on_nonregular_3.rs:33:9
    |
 LL |         Some(Wrapper::Simple::<u32>);
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<u32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<u32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 error[E0320]: overflow while adding drop-check rules for Wrapper<u32>
   --> $DIR/dropck_no_diverge_on_nonregular_3.rs:33:14
    |
 LL |         Some(Wrapper::Simple::<u32>);
    |              ^^^^^^^^^^^^^^^^^^^^^^
    |
-   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<u32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+   = note: overflowed on FingerTree<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<Node<u32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
 
 error: aborting due to 3 previous errors