transpile: Remove static_initializer_is_unsafe (#1745)

- Depends on #1644.

This was already slated for removal in a TODO comment, and it doesn't
seem like it's actually needed. `WithStmts` is handling everything
already. Removing this function helps a little towards #1736 as well.

Author: ahomescu

c2rust-transpile/src/translator/mod.rs

@@ -1631,53 +1631,6 @@ impl<'c> Translation<'c> {
         }
     }
 
-    fn static_initializer_is_unsafe(&self, expr_id: Option<CExprId>, qty: CQualTypeId) -> bool {
-        // SIMD types are always unsafe in statics
-        match self.ast_context.resolve_type(qty.ctype).kind {
-            CTypeKind::Vector(..) => return true,
-            CTypeKind::ConstantArray(ctype, ..) => {
-                let kind = &self.ast_context.resolve_type(ctype).kind;
-
-                if let CTypeKind::Vector(..) = kind {
-                    return true;
-                }
-            }
-            _ => {}
-        }
-
-        // Get the initializer if there is one
-        let expr_id = match expr_id {
-            Some(expr_id) => expr_id,
-            None => return false,
-        };
-
-        // Look for code which can only be translated unsafely
-        let iter = DFExpr::new(&self.ast_context, expr_id.into());
-
-        for i in iter {
-            let expr_id = match i {
-                SomeId::Expr(expr_id) => expr_id,
-                _ => unreachable!("Found static initializer type other than expr"),
-            };
-
-            use CExprKind::*;
-            match self.ast_context[expr_id].kind {
-                ImplicitCast(_, _, cast_kind, _, _) | ExplicitCast(_, _, cast_kind, _, _) => {
-                    use CastKind::*;
-                    match cast_kind {
-                        IntegralToPointer | FunctionToPointerDecay | PointerToIntegral => {
-                            return true;
-                        }
-                        _ => {}
-                    }
-                }
-                _ => {}
-            }
-        }
-
-        false
-    }
-
     /// The purpose of this function is to decide on whether or not a static initializer's
     /// translation is able to be compiled as a valid rust static initializer
     fn static_initializer_is_uncompilable(
@@ -2126,12 +2079,6 @@ impl<'c> Translation<'c> {
                     let mut items = init.stmts_to_items().ok_or_else(|| {
                         format_err!("Expected only item statements in static initializer")
                     })?;
-
-                    // TODO: Replace this by relying entirely on
-                    // WithStmts.is_unsafe() of the translated variable
-                    if self.static_initializer_is_unsafe(initializer, typ) {
-                        init.set_unsafe()
-                    }
                     let init = init.wrap_unsafe().to_pure_expr().unwrap();
                     let item = static_def.span(span).static_item(new_name, ty, init);
                     items.push(item);

c2rust-transpile/src/translator/simd.rs

@@ -295,11 +295,13 @@ impl<'c> Translation<'c> {
     ) -> TranslationResult<WithStmts<Box<Expr>>> {
         let param_translation = self.convert_exprs(ctx, ids, None)?;
         param_translation.and_then_try(|mut params| {
+            let mut is_unsafe = false;
+
             // When used in a const context, we cannot call the standard functions since they
             // are not const and so we are forced to transmute
             let call = if ctx.is_const {
+                is_unsafe = true;
                 let tuple = mk().tuple_expr(params);
-
                 transmute_expr(mk().infer_ty(), mk().infer_ty(), tuple)
             } else {
                 let fn_call_name = match (&self.ast_context[ctype].kind, len) {
@@ -332,14 +334,17 @@ impl<'c> Translation<'c> {
                 mk().call_expr(mk().ident_expr(fn_call_name), params)
             };
 
-            if ctx.is_used() {
-                Ok(WithStmts::new_val(call))
+            let mut val = if ctx.is_used() {
+                WithStmts::new_val(call)
             } else {
-                Ok(WithStmts::new(
+                WithStmts::new(
                     vec![mk().expr_stmt(call)],
                     self.panic_or_err("No value for unused shuffle vector return"),
-                ))
-            }
+                )
+            };
+            val.merge_unsafe(is_unsafe);
+
+            Ok(val)
         })
     }