Auto merge of #3946 - rchaser53:issue-3920, r=flip1995

[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 e63e978e26b76d90df12997d7d183e9dd097c9b5..7e53035d9dce6c518be83cb90a7cea96ae979d19 100644 (file)
--- a/clippy_lints/src/redundant_field_names.rs
+++ b/clippy_lints/src/redundant_field_names.rs
@@ -1,26 +1,32 @@
-use rustc::lint::*;
-use rustc::hir::*;
-use crate::utils::{in_macro, is_range_expression, match_var, span_lint_and_sugg};
+use crate::utils::span_lint_and_sugg;
+use rustc::lint::{EarlyContext, EarlyLintPass, LintArray, LintPass};
+use rustc::{declare_tool_lint, lint_array};
+use rustc_errors::Applicability;
+use syntax::ast::*;
 
-/// **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"
@@ -32,30 +38,34 @@ impl LintPass for RedundantFieldNames {
     fn get_lints(&self) -> LintArray {
         lint_array!(REDUNDANT_FIELD_NAMES)
     }
-}
 
-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) || is_range_expression(expr.span) {
-            return;
-        }
+    fn name(&self) -> &'static str {
+        "RedundantFieldNames"
+    }
+}
 
-        if let ExprStruct(_, ref fields, _) = expr.node {
+impl EarlyLintPass for RedundantFieldNames {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &Expr) {
+        if let ExprKind::Struct(_, ref fields, _) = expr.node {
             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.node {
+                    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,
+                        );
+                    }
                 }
             }
         }