assume_lifetimes: ascribe a lifetime to this regardless of

constness, bringing assume_lifetimes in line with assume_this_lifetimes.

PiperOrigin-RevId: 879636739

Author: zrlk

rs_bindings_from_cc/generate_bindings/lifetime_defaults_transform.rs

@@ -230,10 +230,7 @@ impl<'a> LifetimeDefaults<'a> {
                 new_ty.explicit_lifetimes = self.get_lifetime_for_state(&state);
                 LifetimeResult { ty: new_ty, state, this_state: LifetimeState::Unseen }
             }
-            CcTypeVariant::Pointer(pty)
-                if (is_this && pty.pointee_type.is_const)
-                    || pty.kind == PointerTypeKind::LValueRef =>
-            {
+            CcTypeVariant::Pointer(pty) if is_this || pty.kind == PointerTypeKind::LValueRef => {
                 let LifetimeResult { ty: pointee_type, .. } = self.add_lifetime_to_input_type(
                     false,
                     false,
@@ -454,12 +451,16 @@ impl<'a> LifetimeDefaults<'a> {
             .for_each(|name| new_func.lifetime_inputs.push(self.bindings.push_new_binding(name)));
         self.lower_clang_annotations(&mut new_func)?;
         new_func.params.iter_mut().enumerate().for_each(|(ix, param)| {
-            let is_this = ix == 0 && &*param.identifier.identifier == "__this";
+            let is_constructor = func.cc_name == ir::UnqualifiedIdentifier::Constructor;
+            // `this` in a constructor is strange. The !is_constructor restriction fixes some
+            // situations where we would bind a `'__this` in a constructor and then not use it
+            // (because the actual `__this` is a void*).
+            let is_this = ix == 0 && &*param.identifier.identifier == "__this" && !is_constructor;
             had_this |= is_this;
             let LifetimeResult { ty: new_type, state: new_state, this_state: new_this_state } =
                 self.add_lifetime_to_input_type(
                     is_this,
-                    func.cc_name == ir::UnqualifiedIdentifier::Constructor,
+                    is_constructor,
                     Some(&param.identifier.identifier),
                     &mut new_func.lifetime_inputs,
                     &param.type_,

rs_bindings_from_cc/generate_bindings/lifetime_defaults_transform_test.rs

@@ -899,7 +899,7 @@ fn test_struct_binds_lifetime_param() -> Result<()> {
                 return_type: CcType { ... explicit_lifetimes: ["a"] ... }, ...
                 lifetime_params: [],
                 ...
-                lifetime_inputs: [],
+                lifetime_inputs: ["__this"],
                 ...
             }
         }
@@ -937,7 +937,7 @@ fn test_struct_shadows_unknown_lifetime_param() -> Result<()> {
                 return_type: CcType { ... explicit_lifetimes: ["unknown_0"] ... }, ...
                 lifetime_params: [],
                 ...
-                lifetime_inputs: [],
+                lifetime_inputs: ["__this"],
                 ...
             }
         }
@@ -975,7 +975,7 @@ fn test_struct_does_not_shadow_unrelated_lifetime_param() -> Result<()> {
                 return_type: CcType { ... explicit_lifetimes: ["a"] ... }, ...
                 lifetime_params: [],
                 ...
-                lifetime_inputs: ["a"],
+                lifetime_inputs: ["__this", "a"],
                 ...
             }
         }
@@ -1013,7 +1013,7 @@ fn test_struct_renames_shadowed_lifetime_param_in_function() -> Result<()> {
                 return_type: CcType { ... explicit_lifetimes: ["a_0"] ... }, ...
                 lifetime_params: [],
                 ...
-                lifetime_inputs: ["a_0"],
+                lifetime_inputs: ["a_0", "__this"],
                 ...
             }
         }
@@ -1065,7 +1065,7 @@ fn test_struct_renames_multiple_shadowed_lifetime_param_in_function() -> Result<
                 return_type: CcType { ... explicit_lifetimes: ["a_2"] ... }, ...
                 lifetime_params: [],
                 ...
-                lifetime_inputs: ["a_2"],
+                lifetime_inputs: ["a_2", "__this"],
                 ...
             }
         }
@@ -1117,7 +1117,7 @@ fn test_function_uses_top_of_renamed_lifetime_stack() -> Result<()> {
                 return_type: CcType { ... explicit_lifetimes: ["a_1"] ... }, ...
                 lifetime_params: [],
                 ...
-                lifetime_inputs: [],
+                lifetime_inputs: ["__this"],
                 ...
             }
         }

rs_bindings_from_cc/test/assume_lifetimes/member_function_rs_api.rs

@@ -33,15 +33,10 @@ impl S {
     pub fn int_accessor<'__this>(&'__this self) -> &'__this ::ffi_11::c_int {
         unsafe { crate::detail::__rust_thunk___ZNK1S12int_accessorEv(self) }
     }
-    /// # Safety
-    ///
-    /// The caller must ensure that the following unsafe arguments are not misused by the function:
-    /// * `__this`: raw pointer
-    ///
     /// Generated from: rs_bindings_from_cc/test/assume_lifetimes/member_function.h;l=10
     #[inline(always)]
-    pub unsafe fn me(__this: *mut Self) -> *mut crate::S {
-        crate::detail::__rust_thunk___ZN1S2meEv(__this)
+    pub fn me<'__this>(&'__this mut self) -> &'__this mut crate::S {
+        unsafe { crate::detail::__rust_thunk___ZN1S2meEv(self) }
     }
 }
 
@@ -65,7 +60,9 @@ mod detail {
         pub(crate) unsafe fn __rust_thunk___ZNK1S12int_accessorEv<'__this>(
             __this: &'__this crate::S,
         ) -> &'__this ::ffi_11::c_int;
-        pub(crate) unsafe fn __rust_thunk___ZN1S2meEv(__this: *mut crate::S) -> *mut crate::S;
+        pub(crate) unsafe fn __rust_thunk___ZN1S2meEv<'__this>(
+            __this: &'__this mut crate::S,
+        ) -> &'__this mut crate::S;
     }
 }
 

rs_bindings_from_cc/test/assume_lifetimes/member_function_test.rs

@@ -14,10 +14,7 @@ fn my_test() {
 #[gtest]
 fn self_reference_test() {
     let mut s = member_function::S::default();
-    unsafe {
-        let s_ptr: *mut member_function::S =
-            member_function::S::me(&mut s as *mut member_function::S);
-        let int_field = (*s_ptr).int_accessor();
-        assert_eq!(*int_field, 42);
-    }
+    let s_ref: &mut member_function::S = member_function::S::me(&mut s);
+    let int_field = s_ref.int_accessor();
+    assert_eq!(*int_field, 42);
 }

rs_bindings_from_cc/test/golden/bitfields.h

@@ -5,7 +5,6 @@
 #ifndef CRUBIT_RS_BINDINGS_FROM_CC_TEST_GOLDEN_BITFIELDS_H_
 #define CRUBIT_RS_BINDINGS_FROM_CC_TEST_GOLDEN_BITFIELDS_H_
 
-#pragma clang lifetime_elision
 
 struct WithBitfields {
   int f1 : 2;

rs_bindings_from_cc/test/golden/bitfields_rs_api.rs

@@ -51,32 +51,14 @@ impl Default for WithBitfields {
     }
 }
 
-// Error while generating bindings for constructor 'WithBitfields::WithBitfields':
-// Can't generate bindings for WithBitfields::WithBitfields, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for WithBitfields::WithBitfields (the type of __param_0 (parameter #1): references are not supported)
-
-// Error while generating bindings for constructor 'WithBitfields::WithBitfields':
-// Can't generate bindings for WithBitfields::WithBitfields, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for WithBitfields::WithBitfields (the type of __param_0 (parameter #1): references are not supported)
-
-// Error while generating bindings for function 'WithBitfields::operator=':
-// Can't generate bindings for WithBitfields::operator=, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for WithBitfields::operator= (return type: references are not supported)
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for WithBitfields::operator= (the type of __param_0 (parameter #1): references are not supported)
-
-// Error while generating bindings for function 'WithBitfields::operator=':
-// Can't generate bindings for WithBitfields::operator=, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for WithBitfields::operator= (return type: references are not supported)
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for WithBitfields::operator= (the type of __param_0 (parameter #1): references are not supported)
-
 /// This is a regression test for b/283835873 where the alignment of the
 /// generated struct was wrong/missing.
 ///
 /// # Safety
 ///
 /// To call a function that accepts this type, you must uphold these requirements:
 /// * Document why the following public unsafe fields of this type cannot be misused by callee:
-///   * `status`: Rust type is unknown; safety requirements cannot be automatically generated: Unsupported type 'enum AlignmentRegressionTest::(unnamed at ./rs_bindings_from_cc/test/golden/bitfields.h:26:3)': No generated bindings found for ''
+///   * `status`: Rust type is unknown; safety requirements cannot be automatically generated: Unsupported type 'enum AlignmentRegressionTest::(unnamed at ./rs_bindings_from_cc/test/golden/bitfields.h:25:3)': No generated bindings found for ''
 #[derive(Clone, Copy, ::ctor::MoveAndAssignViaCopy)]
 #[repr(C, align(4))]
 ///CRUBIT_ANNOTATE: cpp_type=AlignmentRegressionTest
@@ -103,24 +85,6 @@ impl Default for AlignmentRegressionTest {
     }
 }
 
-// Error while generating bindings for constructor 'AlignmentRegressionTest::AlignmentRegressionTest':
-// Can't generate bindings for AlignmentRegressionTest::AlignmentRegressionTest, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for AlignmentRegressionTest::AlignmentRegressionTest (the type of __param_0 (parameter #1): references are not supported)
-
-// Error while generating bindings for constructor 'AlignmentRegressionTest::AlignmentRegressionTest':
-// Can't generate bindings for AlignmentRegressionTest::AlignmentRegressionTest, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for AlignmentRegressionTest::AlignmentRegressionTest (the type of __param_0 (parameter #1): references are not supported)
-
-// Error while generating bindings for function 'AlignmentRegressionTest::operator=':
-// Can't generate bindings for AlignmentRegressionTest::operator=, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for AlignmentRegressionTest::operator= (return type: references are not supported)
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for AlignmentRegressionTest::operator= (the type of __param_0 (parameter #1): references are not supported)
-
-// Error while generating bindings for function 'AlignmentRegressionTest::operator=':
-// Can't generate bindings for AlignmentRegressionTest::operator=, because of missing required features (crubit.rs-features):
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for AlignmentRegressionTest::operator= (return type: references are not supported)
-// //rs_bindings_from_cc/test/golden:bitfields_cc needs [//features:experimental] for AlignmentRegressionTest::operator= (the type of __param_0 (parameter #1): references are not supported)
-
 pub mod alignment_regression_test {
     #[allow(unused_imports)]
     use super::*;

rs_bindings_from_cc/test/golden/clang_attrs.h

@@ -5,7 +5,6 @@
 #ifndef CRUBIT_RS_BINDINGS_FROM_CC_TEST_GOLDEN_CLANG_ATTRS_H_
 #define CRUBIT_RS_BINDINGS_FROM_CC_TEST_GOLDEN_CLANG_ATTRS_H_
 
-#pragma clang lifetime_elision
 
 struct alignas(64) HasCustomAlignment {};