Auto merge of #74633 - davidtwco:issue-74614-disable-polymorphisation, r=wesleywiser

Disable polymorphisation

Fixes #74614.

This PR disables polymorphisation to fix the regression in #74614 after investigation into the issue makes it clear that the fix won't be trivial. ~~I'll file an issue shortly to replace #74614 with the findings so far.~~ #74636 has been filed to track the fix of the underlying regression.

r? @eddyb

Author: bors

src/librustc_mir/monomorphize/collector.rs

@@ -627,8 +627,9 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
                     Ok(val) => collect_const_value(self.tcx, val, self.output),
                     Err(ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted) => {}
                     Err(ErrorHandled::TooGeneric) => span_bug!(
-                        self.tcx.def_span(def.did),
-                        "collection encountered polymorphic constant",
+                        self.body.source_info(location).span,
+                        "collection encountered polymorphic constant: {}",
+                        substituted_constant
                     ),
                 }
             }

src/librustc_session/options.rs

@@ -949,7 +949,7 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
         (default: PLT is disabled if full relro is enabled)"),
     polonius: bool = (false, parse_bool, [UNTRACKED],
         "enable polonius-based borrow-checker (default: no)"),
-    polymorphize: bool = (true, parse_bool, [TRACKED],
+    polymorphize: bool = (false, parse_bool, [TRACKED],
           "perform polymorphization analysis"),
     pre_link_arg: (/* redirected to pre_link_args */) = ((), parse_string_push, [UNTRACKED],
         "a single extra argument to prepend the linker invocation (can be used several times)"),

src/test/codegen-units/item-collection/static-init.rs

@@ -1,4 +1,4 @@
-// compile-flags:-Zprint-mono-items=eager
+// compile-flags:-Zprint-mono-items=eager -Zpolymorphize=on
 
 #![feature(start)]
 

src/test/codegen-units/item-collection/trait-method-default-impl.rs

@@ -1,4 +1,4 @@
-// compile-flags:-Zprint-mono-items=eager
+// compile-flags:-Zprint-mono-items=eager -Zpolymorphize=on
 
 #![deny(dead_code)]
 #![feature(start)]

src/test/codegen-units/polymorphization/unused_type_parameters.rs

@@ -1,4 +1,4 @@
-// compile-flags:-Zprint-mono-items=lazy -Copt-level=1
+// compile-flags:-Zpolymorphize=on -Zprint-mono-items=lazy -Copt-level=1
 // ignore-tidy-linelength
 
 #![crate_type = "rlib"]

src/test/ui/issues/issue-74614.rs

@@ -0,0 +1,17 @@
+// build-pass
+
+fn test<T>() {
+    std::mem::size_of::<T>();
+}
+
+pub fn foo<T>(_: T) -> &'static fn() {
+    &(test::<T> as fn())
+}
+
+fn outer<T>() {
+    foo(|| ());
+}
+
+fn main() {
+    outer::<u8>();
+}

src/test/ui/polymorphization/const_parameters/closures.rs

@@ -1,4 +1,5 @@
 // build-fail
+// compile-flags:-Zpolymorphize=on
 #![feature(const_generics, rustc_attrs)]
 //~^ WARN the feature `const_generics` is incomplete
 

src/test/ui/polymorphization/const_parameters/closures.stderr

@@ -1,5 +1,5 @@
 warning: the feature `const_generics` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/closures.rs:2:12
+  --> $DIR/closures.rs:3:12
    |
 LL | #![feature(const_generics, rustc_attrs)]
    |            ^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL | #![feature(const_generics, rustc_attrs)]
    = note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
 
 error: item has unused generic parameters
-  --> $DIR/closures.rs:18:19
+  --> $DIR/closures.rs:19:19
    |
 LL | pub fn unused<const T: usize>() -> usize {
    |                     - generic parameter `T` is unused
@@ -17,13 +17,13 @@ LL |     let add_one = |x: usize| x + 1;
    |                   ^^^^^^^^^^^^^^^^
 
 error: item has unused generic parameters
-  --> $DIR/closures.rs:16:8
+  --> $DIR/closures.rs:17:8
    |
 LL | pub fn unused<const T: usize>() -> usize {
    |        ^^^^^^       - generic parameter `T` is unused
 
 error: item has unused generic parameters
-  --> $DIR/closures.rs:27:19
+  --> $DIR/closures.rs:28:19
    |
 LL | pub fn used_parent<const T: usize>() -> usize {
    |                          - generic parameter `T` is unused
@@ -32,7 +32,7 @@ LL |     let add_one = |x: usize| x + 1;
    |                   ^^^^^^^^^^^^^^^^
 
 error: item has unused generic parameters
-  --> $DIR/closures.rs:47:13
+  --> $DIR/closures.rs:48:13
    |
 LL | pub fn unused_upvar<const T: usize>() -> usize {
    |                           - generic parameter `T` is unused

src/test/ui/polymorphization/const_parameters/functions.rs

@@ -1,4 +1,5 @@
 // build-fail
+// compile-flags:-Zpolymorphize=on
 #![feature(const_generics, rustc_attrs)]
 //~^ WARN the feature `const_generics` is incomplete
 

src/test/ui/polymorphization/const_parameters/functions.stderr

@@ -1,5 +1,5 @@
 warning: the feature `const_generics` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/functions.rs:2:12
+  --> $DIR/functions.rs:3:12
    |
 LL | #![feature(const_generics, rustc_attrs)]
    |            ^^^^^^^^^^^^^^
@@ -8,7 +8,7 @@ LL | #![feature(const_generics, rustc_attrs)]
    = note: see issue #44580 <https://github.com/rust-lang/rust/issues/44580> for more information
 
 error: item has unused generic parameters
-  --> $DIR/functions.rs:14:8
+  --> $DIR/functions.rs:15:8
    |
 LL | pub fn unused<const T: usize>() {
    |        ^^^^^^       - generic parameter `T` is unused