Rollup merge of #83092 - petrochenkov:qspan, r=estebank

[rust.git] / clippy_lints / src / redundant_field_names.rs

diff --git a/clippy_lints/src/redundant_field_names.rs b/clippy_lints/src/redundant_field_names.rs
index 27f890ccd90fc5e6db0e035d43631ee9d10fe514..38dcf7a192c823beadf6e5a07e43f3c013eac754 100644 (file)
--- a/clippy_lints/src/redundant_field_names.rs
+++ b/clippy_lints/src/redundant_field_names.rs
@@ -1,64 +1,86 @@
-use rustc::lint::*;
-use rustc::{declare_lint, lint_array};
-use rustc::hir::*;
-use crate::utils::{in_macro, match_var, span_lint_and_sugg};
+use crate::utils::{meets_msrv, span_lint_and_sugg};
+use rustc_ast::ast::{Expr, ExprKind};
+use rustc_errors::Applicability;
+use rustc_lint::{EarlyContext, EarlyLintPass};
+use rustc_middle::lint::in_external_macro;
+use rustc_semver::RustcVersion;
+use rustc_session::{declare_tool_lint, impl_lint_pass};
+
+const REDUNDANT_FIELD_NAMES_MSRV: RustcVersion = RustcVersion::new(1, 17, 0);
 
-/// **What it does:** Checks for fields in struct literals where shorthands
-/// could be used.
-///
-/// **Why is this bad?** If the field and variable names are the same,
-/// the field name is redundant.
-///
-/// **Known problems:** None.
-///
-/// **Example:**
-/// ```rust
-/// let bar: u8 = 123;
-///
-/// struct Foo {
-///     bar: u8,
-/// }
-///
-/// let foo = Foo{ bar: bar }
-/// ```
 declare_clippy_lint! {
+    /// **What it does:** Checks for fields in struct literals where shorthands
+    /// could be used.
+    ///
+    /// **Why is this bad?** If the field and variable names are the same,
+    /// the field name is redundant.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    /// ```rust
+    /// let bar: u8 = 123;
+    ///
+    /// struct Foo {
+    ///     bar: u8,
+    /// }
+    ///
+    /// let foo = Foo { bar: bar };
+    /// ```
+    /// the last line can be simplified to
+    /// ```ignore
+    /// let foo = Foo { bar };
+    /// ```
     pub REDUNDANT_FIELD_NAMES,
     style,
     "checks for fields in struct literals where shorthands could be used"
 }
 
-pub struct RedundantFieldNames;
+pub struct RedundantFieldNames {
+    msrv: Option<RustcVersion>,
+}
 
-impl LintPass for RedundantFieldNames {
-    fn get_lints(&self) -> LintArray {
-        lint_array!(REDUNDANT_FIELD_NAMES)
+impl RedundantFieldNames {
+    #[must_use]
+    pub fn new(msrv: Option<RustcVersion>) -> Self {
+        Self { msrv }
     }
 }
 
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for RedundantFieldNames {
-    fn check_expr(&mut self, cx: &LateContext<'a, 'tcx>, expr: &'tcx Expr) {
-        // Ignore all macros including range expressions.
-        // They can have redundant field names when expanded.
-        // e.g. range expression `start..end` is desugared to `Range { start: start, end: end }`
-        if in_macro(expr.span) {
+impl_lint_pass!(RedundantFieldNames => [REDUNDANT_FIELD_NAMES]);
+
+impl EarlyLintPass for RedundantFieldNames {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
+        if !meets_msrv(self.msrv.as_ref(), &REDUNDANT_FIELD_NAMES_MSRV) {
             return;
         }
 
-        if let ExprKind::Struct(_, ref fields, _) = expr.node {
+        if in_external_macro(cx.sess, expr.span) {
+            return;
+        }
+        if let ExprKind::Struct(_, ref fields, _) = expr.kind {
             for field in fields {
-                let name = field.ident.name;
-
-                if match_var(&field.expr, name) && !field.is_shorthand {
-                    span_lint_and_sugg (
-                        cx,
-                        REDUNDANT_FIELD_NAMES,
-                        field.span,
-                        "redundant field names in struct initialization",
-                        "replace it with",
-                        name.to_string()
-                    );
+                if field.is_shorthand {
+                    continue;
+                }
+                if let ExprKind::Path(None, path) = &field.expr.kind {
+                    if path.segments.len() == 1
+                        && path.segments[0].ident == field.ident
+                        && path.segments[0].args.is_none()
+                    {
+                        span_lint_and_sugg(
+                            cx,
+                            REDUNDANT_FIELD_NAMES,
+                            field.span,
+                            "redundant field names in struct initialization",
+                            "replace it with",
+                            field.ident.to_string(),
+                            Applicability::MachineApplicable,
+                        );
+                    }
                 }
             }
         }
     }
+    extract_msrv_attr!(EarlyContext);
 }