[pylint] Implement import-outside-toplevel (C0415)

crates/ruff_linter/resources/test/fixtures/pylint/import_outside_toplevel.py

@@ -0,0 +1,20 @@
+def print_python_version():
+    import sys  # C0415
+
+    print(sys.version_info)
+
+def print_python_version():
+    import sys, string  # C0415
+
+    print(sys.version_info, string.ascii.digits)
+
+# OK
+import sys 
+
+
+def print_python_version():
+    print(sys.version_info)
+
+# OK
+if True:
+    import sys

crates/ruff_linter/src/checkers/ast/analyze/statement.rs

@@ -530,6 +530,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.enabled(Rule::ModuleImportNotAtTopOfFile) {
                 pycodestyle::rules::module_import_not_at_top_of_file(checker, stmt);
             }
+            if checker.enabled(Rule::ImportOutsideToplevel) {
+                pylint::rules::import_outside_toplevel(checker, stmt, names);
+            }
             if checker.enabled(Rule::GlobalStatement) {
                 for name in names {
                     if let Some(asname) = name.asname.as_ref() {

crates/ruff_linter/src/codes.rs

@@ -211,6 +211,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Pylint, "C0205") => (RuleGroup::Stable, rules::pylint::rules::SingleStringSlots),
         (Pylint, "C0208") => (RuleGroup::Stable, rules::pylint::rules::IterationOverSet),
         (Pylint, "C0414") => (RuleGroup::Stable, rules::pylint::rules::UselessImportAlias),
+        (Pylint, "C0415") => (RuleGroup::Preview, rules::pylint::rules::ImportOutsideToplevel),
         (Pylint, "C2401") => (RuleGroup::Preview, rules::pylint::rules::NonAsciiName),
         (Pylint, "C2403") => (RuleGroup::Preview, rules::pylint::rules::NonAsciiImportName),
         #[allow(deprecated)]

crates/ruff_linter/src/rules/pylint/mod.rs

@@ -142,6 +142,7 @@ mod tests {
     #[test_case(Rule::UnnecessaryLambda, Path::new("unnecessary_lambda.py"))]
     #[test_case(Rule::NonAsciiImportName, Path::new("non_ascii_module_import.py"))]
     #[test_case(Rule::NonAsciiName, Path::new("non_ascii_name.py"))]
+    #[test_case(Rule::ImportOutsideToplevel, Path::new("import_outside_toplevel.py"))]
     fn rules(rule_code: Rule, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", rule_code.noqa_code(), path.to_string_lossy());
         let diagnostics = test_path(

crates/ruff_linter/src/rules/pylint/rules/import_outside_toplevel.rs

@@ -0,0 +1,43 @@
+use ruff_diagnostics::{Diagnostic, Violation};
+use ruff_macros::{derive_message_formats, violation};
+use ruff_python_ast::{Alias, Stmt};
+use ruff_text_size::Ranged;
+
+use crate::checkers::ast::Checker;
+
+/// ## What it does
+/// Checks for import statements outside of the module level.
+///
+/// ## Why is this bad?
+/// Module imports should be grouped at the top of the file at the module level
+/// as required by PEP-8.
+///
+/// https://peps.python.org/pep-0008/#imports
+#[violation]
+pub struct ImportOutsideToplevel {
+    names: String,
+}
+
+impl Violation for ImportOutsideToplevel {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        let Self { names } = self;
+        format!("Import outside toplevel ({names})")
+    }
+}
+
+/// C0415
+pub(crate) fn import_outside_toplevel(checker: &mut Checker, stmt: &Stmt, names: &[Alias]) {
+    if !checker.semantic().current_scope().kind.is_module() {
+        let names: String = names
+            .iter()
+            .map(|name| name.name.clone().to_string())
+            .collect::<Vec<String>>()
+            .join(", ");
+
+        checker.diagnostics.push(Diagnostic::new(
+            ImportOutsideToplevel { names },
+            stmt.range(),
+        ));
+    }
+}

crates/ruff_linter/src/rules/pylint/rules/mod.rs

@@ -17,6 +17,7 @@ pub(crate) use eq_without_hash::*;
 pub(crate) use global_at_module_level::*;
 pub(crate) use global_statement::*;
 pub(crate) use global_variable_not_assigned::*;
+pub(crate) use import_outside_toplevel::*;
 pub(crate) use import_self::*;
 pub(crate) use invalid_all_format::*;
 pub(crate) use invalid_all_object::*;
@@ -85,6 +86,7 @@ mod eq_without_hash;
 mod global_at_module_level;
 mod global_statement;
 mod global_variable_not_assigned;
+mod import_outside_toplevel;
 mod import_self;
 mod invalid_all_format;
 mod invalid_all_object;

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLC0415_import_outside_toplevel.py.snap

@@ -0,0 +1,22 @@
+---
+source: crates/ruff_linter/src/rules/pylint/mod.rs
+---
+import_outside_toplevel.py:2:5: PLC0415 Import outside toplevel (sys)
+  |
+1 | def print_python_version():
+2 |     import sys  # C0415
+  |     ^^^^^^^^^^ PLC0415
+3 | 
+4 |     print(sys.version_info)
+  |
+
+import_outside_toplevel.py:7:5: PLC0415 Import outside toplevel (sys, string)
+  |
+6 | def print_python_version():
+7 |     import sys, string  # C0415
+  |     ^^^^^^^^^^^^^^^^^^ PLC0415
+8 | 
+9 |     print(sys.version_info, string.ascii.digits)
+  |
+
+