transpile: Cast assignment result to expected type if needed

Author: Rua

c2rust-transpile/src/translator/operators.rs

@@ -318,8 +318,8 @@ impl<'c> Translation<'c> {
     fn convert_assignment_operator_with_rhs(
         &self,
         ctx: ExprContext,
-        _expected_type_id: Option<CQualTypeId>,
-        _result_type_id: CQualTypeId,
+        expected_type_id: Option<CQualTypeId>,
+        result_type_id: CQualTypeId,
         op: CBinOp,
         lhs: CExprId,
         rhs_type_id: CQualTypeId,
@@ -485,9 +485,18 @@ impl<'c> Translation<'c> {
                     }
                 };
 
-                Ok(assign_stmt.and_then(|assign_stmt| {
-                    WithStmts::new(vec![mk().semi_stmt(assign_stmt)], read)
-                }))
+                let assign_result = self.make_cast(
+                    ctx,
+                    result_type_id,
+                    expected_type_id.unwrap_or(result_type_id),
+                    WithStmts::new_val(read),
+                )?;
+
+                Ok(assign_stmt
+                    .zip(assign_result)
+                    .and_then(|(assign_stmt, assign_result)| {
+                        WithStmts::new(vec![mk().semi_stmt(assign_stmt)], assign_result)
+                    }))
             })
     }
 

c2rust-transpile/tests/snapshots.rs

@@ -391,7 +391,7 @@ fn test_empty_init() {
 
 #[test]
 fn test_exprs() {
-    transpile("exprs.c").expect_compile_error(true).run();
+    transpile("exprs.c").run();
 }
 
 #[test]

c2rust-transpile/tests/snapshots/snapshots__transpile@exprs.c.2021.clang15.snap

@@ -139,7 +139,7 @@ pub unsafe extern "C" fn pointer_arithmetic() {
 pub unsafe extern "C" fn assign_result() {
     let mut l: ::core::ffi::c_ulong = 0 as ::core::ffi::c_ulong;
     l = 1 as ::core::ffi::c_ulong;
-    let mut s1: size_t = l;
+    let mut s1: size_t = l as size_t;
     l = l.wrapping_add(2 as ::core::ffi::c_ulong);
-    let mut s2: size_t = l;
+    let mut s2: size_t = l as size_t;
 }

c2rust-transpile/tests/snapshots/snapshots__transpile@exprs.c.2024.clang15.snap

@@ -139,7 +139,7 @@ pub unsafe extern "C" fn pointer_arithmetic() {
 pub unsafe extern "C" fn assign_result() {
     let mut l: ::core::ffi::c_ulong = 0 as ::core::ffi::c_ulong;
     l = 1 as ::core::ffi::c_ulong;
-    let mut s1: size_t = l;
+    let mut s1: size_t = l as size_t;
     l = l.wrapping_add(2 as ::core::ffi::c_ulong);
-    let mut s2: size_t = l;
+    let mut s2: size_t = l as size_t;
 }