-use crate::utils::{in_macro, snippet_with_applicability, span_lint_and_sugg};
+use crate::utils::{in_macro, snippet, snippet_with_applicability, span_lint_and_sugg};
use if_chain::if_chain;
use rustc_errors::Applicability;
use rustc_hir::{
def::{DefKind, Res},
- Item, ItemKind, UseKind,
+ Item, ItemKind, PathSegment, UseKind,
};
use rustc_lint::{LateContext, LateLintPass};
-use rustc_session::{declare_lint_pass, declare_tool_lint};
-use rustc_span::BytePos;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+use rustc_span::symbol::kw;
+use rustc_span::{sym, BytePos};
declare_clippy_lint! {
/// **What it does:** Checks for `use Enum::*`.
/// still around.
///
/// **Example:**
- /// ```rust
+ /// ```rust,ignore
+ /// // Bad
/// use std::cmp::Ordering::*;
+ /// foo(Less);
+ ///
+ /// // Good
+ /// use std::cmp::Ordering;
+ /// foo(Ordering::Less)
/// ```
pub ENUM_GLOB_USE,
pedantic,
declare_clippy_lint! {
/// **What it does:** Checks for wildcard imports `use _::*`.
///
- /// **Why is this bad?** wildcard imports can polute the namespace. This is especially bad if
+ /// **Why is this bad?** wildcard imports can pollute the namespace. This is especially bad if
/// you try to import something through a wildcard, that already has been imported by name from
/// a different source:
///
///
/// This can lead to confusing error messages at best and to unexpected behavior at worst.
///
+ /// **Exceptions:**
+ ///
+ /// Wildcard imports are allowed from modules named `prelude`. Many crates (including the standard library)
+ /// provide modules named "prelude" specifically designed for wildcard import.
+ ///
+ /// `use super::*` is allowed in test modules. This is defined as any module with "test" in the name.
+ ///
+ /// These exceptions can be disabled using the `warn-on-all-wildcard-imports` configuration flag.
+ ///
/// **Known problems:** If macros are imported through the wildcard, this macro is not included
/// by the suggestion and has to be added by hand.
///
+ /// Applying the suggestion when explicit imports of the things imported with a glob import
+ /// exist, may result in `unused_imports` warnings.
+ ///
/// **Example:**
///
- /// Bad:
/// ```rust,ignore
+ /// // Bad
/// use crate1::*;
///
/// foo();
/// ```
///
- /// Good:
/// ```rust,ignore
+ /// // Good
/// use crate1::foo;
///
/// foo();
"lint `use _::*` statements"
}
-declare_lint_pass!(WildcardImports => [ENUM_GLOB_USE, WILDCARD_IMPORTS]);
+#[derive(Default)]
+pub struct WildcardImports {
+ warn_on_all: bool,
+ test_modules_deep: u32,
+}
-impl LateLintPass<'_, '_> for WildcardImports {
- fn check_item(&mut self, cx: &LateContext<'_, '_>, item: &Item<'_>) {
+impl WildcardImports {
+ pub fn new(warn_on_all: bool) -> Self {
+ Self {
+ warn_on_all,
+ test_modules_deep: 0,
+ }
+ }
+}
+
+impl_lint_pass!(WildcardImports => [ENUM_GLOB_USE, WILDCARD_IMPORTS]);
+
+impl LateLintPass<'_> for WildcardImports {
+ fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
+ if is_test_module_or_function(item) {
+ self.test_modules_deep = self.test_modules_deep.saturating_add(1);
+ }
if item.vis.node.is_pub() || item.vis.node.is_pub_restricted() {
return;
}
if_chain! {
- if !in_macro(item.span);
if let ItemKind::Use(use_path, UseKind::Glob) = &item.kind;
- // don't lint prelude glob imports
- if !use_path.segments.iter().last().map_or(false, |ps| ps.ident.as_str() == "prelude");
- let used_imports = cx.tcx.names_imported_by_glob_use(item.hir_id.owner_def_id());
+ if self.warn_on_all || !self.check_exceptions(item, use_path.segments);
+ let used_imports = cx.tcx.names_imported_by_glob_use(item.def_id);
if !used_imports.is_empty(); // Already handled by `unused_imports`
then {
let mut applicability = Applicability::MachineApplicable;
- let import_source = snippet_with_applicability(cx, use_path.span, "..", &mut applicability);
- let (span, braced_glob) = if import_source.is_empty() {
+ let import_source_snippet = snippet_with_applicability(cx, use_path.span, "..", &mut applicability);
+ let (span, braced_glob) = if import_source_snippet.is_empty() {
// This is a `_::{_, *}` import
+ // In this case `use_path.span` is empty and ends directly in front of the `*`,
+ // so we need to extend it by one byte.
(
use_path.span.with_hi(use_path.span.hi() + BytePos(1)),
true,
)
} else {
+ // In this case, the `use_path.span` ends right before the `::*`, so we need to
+ // extend it up to the `*`. Since it is hard to find the `*` in weird
+ // formattings like `use _ :: *;`, we extend it up to, but not including the
+ // `;`. In nested imports, like `use _::{inner::*, _}` there is no `;` and we
+ // can just use the end of the item span
+ let mut span = use_path.span.with_hi(item.span.hi());
+ if snippet(cx, span, "").ends_with(';') {
+ span = use_path.span.with_hi(item.span.hi() - BytePos(1));
+ }
(
- use_path.span.with_hi(use_path.span.hi() + BytePos(3)),
- false,
+ span, false,
)
};
}
};
- let sugg = if import_source.is_empty() {
+ let sugg = if braced_glob {
imports_string
} else {
- format!("{}::{}", import_source, imports_string)
+ format!("{}::{}", import_source_snippet, imports_string)
};
let (lint, message) = if let Res::Def(DefKind::Enum, _) = use_path.res {
}
}
}
+
+ fn check_item_post(&mut self, _: &LateContext<'_>, item: &Item<'_>) {
+ if is_test_module_or_function(item) {
+ self.test_modules_deep = self.test_modules_deep.saturating_sub(1);
+ }
+ }
+}
+
+impl WildcardImports {
+ fn check_exceptions(&self, item: &Item<'_>, segments: &[PathSegment<'_>]) -> bool {
+ in_macro(item.span)
+ || is_prelude_import(segments)
+ || (is_super_only_import(segments) && self.test_modules_deep > 0)
+ }
+}
+
+// Allow "...prelude::..::*" imports.
+// Many crates have a prelude, and it is imported as a glob by design.
+fn is_prelude_import(segments: &[PathSegment<'_>]) -> bool {
+ segments.iter().any(|ps| ps.ident.name == sym::prelude)
+}
+
+// Allow "super::*" imports in tests.
+fn is_super_only_import(segments: &[PathSegment<'_>]) -> bool {
+ segments.len() == 1 && segments[0].ident.name == kw::Super
+}
+
+fn is_test_module_or_function(item: &Item<'_>) -> bool {
+ matches!(item.kind, ItemKind::Mod(..)) && item.ident.name.as_str().contains("test")
}
projects / rust.git / blobdiff