Auto merge of #76219 - Mark-Simulacrum:extern-require-abi, r=estebank

Add allow-by-default lint on implicit ABI in extern function pointers and items

This adds a new lint, missing_abi, which lints on omitted ABIs on extern blocks, function declarations, and function pointers.

It is currently not emitting the best possible diagnostics -- we need to track the span of "extern" at least or do some heuristic searching based on the available spans -- but seems good enough for an initial pass than can be expanded in future PRs.

This is a pretty large PR, but mostly due to updating a large number of tests to include ABIs; I can split that into a separate PR if it would be helpful, but test updates are already in dedicated commits.

11 files changed, 23 insertions, 23 deletions

diff --git a/src/test/ui/consts/auxiliary/cci_const.rs b/src/test/ui/consts/auxiliary/cci_const.rs
index af6a5ad8ed3..c83b3f4a5bb 100644
--- a/src/test/ui/consts/auxiliary/cci_const.rs
+++ b/src/test/ui/consts/auxiliary/cci_const.rs
@@ -1,4 +1,4 @@
-pub extern fn bar() {
+pub extern "C" fn bar() {
 }
 
 pub const foopy: &'static str = "hi there";
diff --git a/src/test/ui/consts/auxiliary/issue-63226.rs b/src/test/ui/consts/auxiliary/issue-63226.rs
index 39cc01a415e..2dc9539ba52 100644
--- a/src/test/ui/consts/auxiliary/issue-63226.rs
+++ b/src/test/ui/consts/auxiliary/issue-63226.rs
@@ -1,5 +1,5 @@
 pub struct VTable{
-    state:extern fn(),
+    state:extern "C" fn(),
 }
 
 impl VTable{
@@ -11,4 +11,4 @@ impl VTable{
         &VTable{state};
 }
 
-extern fn state() {}
+extern "C" fn state() {}
diff --git a/src/test/ui/consts/const-cast.rs b/src/test/ui/consts/const-cast.rs
index 0d8609e334a..abeb24121eb 100644
--- a/src/test/ui/consts/const-cast.rs
+++ b/src/test/ui/consts/const-cast.rs
@@ -7,7 +7,7 @@ struct TestStruct {
 
 unsafe impl Sync for TestStruct {}
 
-extern fn foo() {}
+extern "C" fn foo() {}
 const x: extern "C" fn() = foo;
 static y: TestStruct = TestStruct { x: x as *const u8 };
 
diff --git a/src/test/ui/consts/const-eval/extern_fat_pointer.rs b/src/test/ui/consts/const-eval/extern_fat_pointer.rs
index f210d1a0a90..d91d07827dc 100644
--- a/src/test/ui/consts/const-eval/extern_fat_pointer.rs
+++ b/src/test/ui/consts/const-eval/extern_fat_pointer.rs
@@ -2,7 +2,7 @@
 
 #![feature(extern_types)]
 
-extern {
+extern "C" {
     type Opaque;
 }
 
diff --git a/src/test/ui/consts/const-extern-fn/const-extern-fn-call-extern-fn.rs b/src/test/ui/consts/const-extern-fn/const-extern-fn-call-extern-fn.rs
index e18e0a83573..ee07dfae47c 100644
--- a/src/test/ui/consts/const-extern-fn/const-extern-fn-call-extern-fn.rs
+++ b/src/test/ui/consts/const-extern-fn/const-extern-fn-call-extern-fn.rs
@@ -4,16 +4,16 @@ extern "C" {
     fn regular_in_block();
 }
 
-const extern fn bar() {
+const extern "C" fn bar() {
     unsafe {
         regular_in_block();
         //~^ ERROR: calls in constant functions
     }
 }
 
-extern fn regular() {}
+extern "C" fn regular() {}
 
-const extern fn foo() {
+const extern "C" fn foo() {
     unsafe {
         regular();
         //~^ ERROR: calls in constant functions
diff --git a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs
index 645a957949c..76380ebcb65 100644
--- a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs
+++ b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.rs
@@ -1,10 +1,10 @@
 #![feature(const_extern_fn)]
 
-const extern fn unsize(x: &[u8; 3]) -> &[u8] { x }
+const extern "C" fn unsize(x: &[u8; 3]) -> &[u8] { x }
 const unsafe extern "C" fn closure() -> fn() { || {} }
 //~^ ERROR function pointer
 //~| ERROR function pointer cast
-const unsafe extern fn use_float() { 1.0 + 1.0; }
+const unsafe extern "C" fn use_float() { 1.0 + 1.0; }
 //~^ ERROR floating point arithmetic
 const extern "C" fn ptr_cast(val: *const u8) { val as usize; }
 //~^ ERROR casting pointers to integers
diff --git a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr
index 694e2290808..80d234b0e88 100644
--- a/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr
+++ b/src/test/ui/consts/const-extern-fn/const-extern-fn-min-const-fn.stderr
@@ -17,10 +17,10 @@ LL | const unsafe extern "C" fn closure() -> fn() { || {} }
    = help: add `#![feature(const_fn_fn_ptr_basics)]` to the crate attributes to enable
 
 error[E0658]: floating point arithmetic is not allowed in constant functions
-  --> $DIR/const-extern-fn-min-const-fn.rs:7:38
+  --> $DIR/const-extern-fn-min-const-fn.rs:7:42
    |
-LL | const unsafe extern fn use_float() { 1.0 + 1.0; }
-   |                                      ^^^^^^^^^
+LL | const unsafe extern "C" fn use_float() { 1.0 + 1.0; }
+   |                                          ^^^^^^^^^
    |
    = note: see issue #57241 <https://github.com/rust-lang/rust/issues/57241> for more information
    = help: add `#![feature(const_fn_floating_point_arithmetic)]` to the crate attributes to enable
diff --git a/src/test/ui/consts/const-extern-fn/const-extern-fn-requires-unsafe.rs b/src/test/ui/consts/const-extern-fn/const-extern-fn-requires-unsafe.rs
index cab175bbfa8..71e6c2cb858 100644
--- a/src/test/ui/consts/const-extern-fn/const-extern-fn-requires-unsafe.rs
+++ b/src/test/ui/consts/const-extern-fn/const-extern-fn-requires-unsafe.rs
@@ -1,6 +1,6 @@
 #![feature(const_extern_fn)]
 
-const unsafe extern fn foo() -> usize { 5 }
+const unsafe extern "C" fn foo() -> usize { 5 }
 
 fn main() {
     let a: [u8; foo()];
diff --git a/src/test/ui/consts/const-extern-fn/const-extern-fn.rs b/src/test/ui/consts/const-extern-fn/const-extern-fn.rs
index 1dc0f83cadf..2ce2eafd545 100644
--- a/src/test/ui/consts/const-extern-fn/const-extern-fn.rs
+++ b/src/test/ui/consts/const-extern-fn/const-extern-fn.rs
@@ -1,7 +1,7 @@
 // run-pass
 #![feature(const_extern_fn)]
 
-const extern fn foo1(val: u8) -> u8 {
+const extern "C" fn foo1(val: u8) -> u8 {
     val + 1
 }
 
@@ -9,7 +9,7 @@ const extern "C" fn foo2(val: u8) -> u8 {
     val + 1
 }
 
-const unsafe extern fn bar1(val: bool) -> bool {
+const unsafe extern "C" fn bar1(val: bool) -> bool {
     !val
 }
 
@@ -28,8 +28,8 @@ fn main() {
     assert!(bar1_res);
     assert_eq!(bar1_res, bar2_res);
 
-    let _foo1_cast: extern fn(u8) -> u8 = foo1;
-    let _foo2_cast: extern fn(u8) -> u8 = foo2;
-    let _bar1_cast: unsafe extern fn(bool) -> bool = bar1;
-    let _bar2_cast: unsafe extern fn(bool) -> bool = bar2;
+    let _foo1_cast: extern "C" fn(u8) -> u8 = foo1;
+    let _foo2_cast: extern "C" fn(u8) -> u8 = foo2;
+    let _bar1_cast: unsafe extern "C" fn(bool) -> bool = bar1;
+    let _bar2_cast: unsafe extern "C" fn(bool) -> bool = bar2;
 }
diff --git a/src/test/ui/consts/const-extern-function.rs b/src/test/ui/consts/const-extern-function.rs
index cfcf99b867a..01f487a7d75 100644
--- a/src/test/ui/consts/const-extern-function.rs
+++ b/src/test/ui/consts/const-extern-function.rs
@@ -1,7 +1,7 @@
 // run-pass
 #![allow(non_upper_case_globals)]
 
-extern fn foopy() {}
+extern "C" fn foopy() {}
 
 static f: extern "C" fn() = foopy;
 static s: S = S { f: foopy };
diff --git a/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs b/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs
index 96a8a8452ed..09c7d5580de 100644
--- a/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs
+++ b/src/test/ui/consts/const-size_of_val-align_of_val-extern-type.rs
@@ -2,9 +2,9 @@
 #![feature(core_intrinsics)]
 #![feature(const_size_of_val, const_align_of_val)]
 
-use std::intrinsics::{size_of_val, min_align_of_val};
+use std::intrinsics::{min_align_of_val, size_of_val};
 
-extern {
+extern "C" {
     type Opaque;
 }