Return None more consistently, see also #150

Author: davidhalter

crates/zuban_python/src/file/inference.rs

@@ -780,10 +780,13 @@ impl<'db, 'file> Inference<'db, 'file, '_> {
                     }
                     if let Some(return_type) = other.return_type {
                         Inferred::from_type(return_type)
-                    } else if result_context.expect_not_none() {
-                        from.add_issue(i_s, IssueKind::DoesNotReturnAValue("Function".into()));
-                        Inferred::new_any_from_error()
                     } else {
+                        if result_context.expect_not_none() {
+                            from.add_issue(i_s, IssueKind::DoesNotReturnAValue("Function".into()));
+                            if i_s.db.project.settings.mypy_compatible {
+                                return Inferred::new_any_from_error();
+                            }
+                        }
                         Inferred::new_none()
                     }
                 } else {
@@ -4778,10 +4781,11 @@ pub fn await_(
     }
     if expect_not_none && matches!(t, Type::None) {
         from.add_issue(i_s, IssueKind::DoesNotReturnAValue("Function".into()));
-        Inferred::new_any_from_error()
-    } else {
-        Inferred::from_type(t)
+        if i_s.db.project.settings.mypy_compatible {
+            return Inferred::new_any_from_error();
+        }
     }
+    Inferred::from_type(t)
 }
 
 fn targets_len_infos(targets: TargetIterator) -> (usize, TupleLenInfos) {

crates/zuban_python/src/name.rs

@@ -2,8 +2,7 @@ use std::borrow::Cow;
 
 use lsp_types::SymbolKind;
 use parsa_python_cst::{
-    AssignmentContent, ClassDef, DefiningStmt, FunctionDef, Name as CSTName, NameParent, NodeIndex,
-    PrimaryTargetOrAtom, Scope, Target, TypeLike,
+    ClassDef, DefiningStmt, FunctionDef, Name as CSTName, NameParent, NodeIndex, Scope, TypeLike,
 };
 use vfs::NormalizedPath;
 

crates/zuban_python/src/type_helpers/callable.rs

@@ -74,7 +74,9 @@ impl<'a> Callable<'a> {
                         .into(),
                 ),
             );
-            return Inferred::new_any_from_error();
+            if i_s.db.project.settings.mypy_compatible {
+                return Inferred::new_any_from_error();
+            }
         }
         self.execute_for_custom_return_type(
             i_s,

crates/zuban_python/tests/mypylike/tests/functions.test

@@ -409,9 +409,27 @@ def four(*args: int) -> int: ...
 [case function_no_return_should_not_result_in_any_no_mypy_compatible]
 # flags: --no-mypy-compatible
 # From GH #150, see also the discussion there, Mypy returns Any, Pyright None
-from typing import assert_type
+from typing import assert_type, Callable, Generator, Iterator
 
 def foo() -> None: ...
 
+def bar(c: Callable[[], None]):
+    val = c()  # E: Function does not return a value (it only ever returns None)
+    assert_type(val, None)
+
+async def asyn(depth: int) -> None:
+    if depth > 0:
+        val = await asyn(depth - 1)  # E: Function does not return a value (it only ever returns None)
+        assert_type(val, None)
+
+def generator():
+    def gen() -> Iterator[int]:
+        yield 1
+        return None
+
+    val = yield from gen()  # E: Function does not return a value (it only ever returns None)
+    assert_type(val, None)
+
+
 val = foo()  # E: "foo" does not return a value (it only ever returns None)
 assert_type(val, None)