Merge pull request RustPython#4274 from youknowone/let-else

Apply let-else statements

Author: DimitrisJim

README.md

@@ -20,7 +20,7 @@ A Python-3 (CPython >= 3.10.0) Interpreter written in Rust :snake: :scream:
 
 #### Check out our [online demo](https://rustpython.github.io/demo/) running on WebAssembly.
 
-RustPython requires Rust latest stable version (e.g 1.43.0 at May 24th 2020). 
+RustPython requires Rust latest stable version (e.g 1.65.0 at November 10th 2022).
 To check Rust version: `rustc --version` If you wish to update,
 `rustup update stable`.
 

compiler/codegen/src/compile.rs

@@ -1412,9 +1412,7 @@ impl Compiler {
     ) -> CompileResult<()> {
         let with_location = self.current_source_location;
 
-        let (item, items) = if let Some(parts) = items.split_first() {
-            parts
-        } else {
+        let Some((item, items)) = items.split_first() else {
             return Err(self.error(CodegenErrorType::EmptyWithItems));
         };
 

compiler/parser/build.rs

@@ -17,9 +17,7 @@ fn main() -> anyhow::Result<()> {
 }
 
 fn requires_lalrpop(source: &str, target: &str) -> Option<String> {
-    let target = if let Ok(target) = File::open(target) {
-        target
-    } else {
+    let Ok(target) = File::open(target) else {
         return Some("python.rs doesn't exist. regenerate.".to_owned());
     };
 
@@ -71,9 +69,7 @@ fn requires_lalrpop(source: &str, target: &str) -> Option<String> {
 }
 
 fn try_lalrpop(source: &str, target: &str) -> anyhow::Result<()> {
-    let _message = if let Some(msg) = requires_lalrpop(source, target) {
-        msg
-    } else {
+    let Some(_message) = requires_lalrpop(source, target) else {
         return Ok(());
     };
 

stdlib/src/scproxy.rs

@@ -33,9 +33,7 @@ mod _scproxy {
 
     #[pyfunction]
     fn _get_proxy_settings(vm: &VirtualMachine) -> PyResult<Option<PyDictRef>> {
-        let proxy_dict = if let Some(p) = proxy_dict() {
-            p
-        } else {
+        let Some(proxy_dict) = proxy_dict() else {
             return Ok(None);
         };
 
@@ -73,9 +71,7 @@ mod _scproxy {
 
     #[pyfunction]
     fn _get_proxies(vm: &VirtualMachine) -> PyResult<Option<PyDictRef>> {
-        let proxy_dict = if let Some(p) = proxy_dict() {
-            p
-        } else {
+        let Some(proxy_dict) = proxy_dict() else {
             return Ok(None);
         };
 

vm/src/builtins/function.rs

@@ -392,13 +392,12 @@ impl PyFunction {
     fn set_qualname(&self, value: PySetterValue, vm: &VirtualMachine) -> PyResult<()> {
         match value {
             PySetterValue::Assign(value) => {
-                if let Ok(qualname) = value.downcast::<PyStr>() {
-                    *self.qualname.lock() = qualname;
-                } else {
+                let Ok(qualname) = value.downcast::<PyStr>() else {
                     return Err(vm.new_type_error(
                         "__qualname__ must be set to a string object".to_string(),
                     ));
-                }
+                };
+                *self.qualname.lock() = qualname;
             }
             PySetterValue::Delete => {
                 return Err(

vm/src/builtins/type.rs

@@ -959,9 +959,7 @@ impl GetAttr for PyType {
             ))
         }
 
-        let name = if let Some(name) = vm.ctx.interned_str(&*name_str) {
-            name
-        } else {
+        let Some(name) = vm.ctx.interned_str(&*name_str) else {
             return Err(attribute_error(zelf, name_str.as_str(), vm));
         };
         vm_trace!("type.__getattribute__({:?}, {:?})", zelf, name);

vm/src/dictdatatype.rs

@@ -586,9 +586,7 @@ impl<T: Clone> Dict<T> {
         pred: impl Fn(&T) -> Result<bool, E>,
     ) -> Result<PopInnerResult<T>, E> {
         let (entry_index, index_index) = lookup;
-        let entry_index = if let Some(entry_index) = entry_index.index() {
-            entry_index
-        } else {
+        let Some(entry_index) = entry_index.index() else {
             return Ok(ControlFlow::Break(None));
         };
         let inner = &mut *self.write();

vm/src/exceptions.rs

@@ -524,9 +524,9 @@ impl PyBaseException {
     #[pymethod(magic)]
     fn reduce(zelf: PyRef<Self>, vm: &VirtualMachine) -> PyTupleRef {
         if let Some(dict) = zelf.as_object().dict().filter(|x| !x.is_empty()) {
-            return vm.new_tuple((zelf.class().to_owned(), zelf.args(), dict));
+            vm.new_tuple((zelf.class().to_owned(), zelf.args(), dict))
         } else {
-            return vm.new_tuple((zelf.class().to_owned(), zelf.args()));
+            vm.new_tuple((zelf.class().to_owned(), zelf.args()))
         }
     }
 }

vm/src/protocol/number.rs

@@ -243,9 +243,7 @@ impl PyNumber<'_> {
 
     // PyNumber_Check
     pub fn check(obj: &PyObject) -> bool {
-        let methods = if let Some(m) = Self::find_methods(obj) {
-            m
-        } else {
+        let Some(methods) = Self::find_methods(obj) else {
             return false;
         };
         let methods = methods.as_ref();

vm/src/stdlib/itertools.rs

@@ -110,9 +110,7 @@ mod decl {
     impl IterNextIterable for PyItertoolsChain {}
     impl IterNext for PyItertoolsChain {
         fn next(zelf: &Py<Self>, vm: &VirtualMachine) -> PyResult<PyIterReturn> {
-            let source = if let Some(source) = zelf.source.read().clone() {
-                source
-            } else {
+            let Some(source) = zelf.source.read().clone() else {
                 return Ok(PyIterReturn::StopIteration(None));
             };
             let next = loop {