Add exhaustive_structs lint

clippy_lints/src/exhaustive_items.rs

@@ -1,7 +1,7 @@
 use crate::utils::{snippet_opt, span_lint_and_help, span_lint_and_sugg};
 use if_chain::if_chain;
-use rustc_hir::{Item, ItemKind};
 use rustc_errors::Applicability;
+use rustc_hir::{Item, ItemKind};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 use rustc_span::sym;
@@ -10,7 +10,8 @@ declare_clippy_lint! {
     /// **What it does:** Warns on any exported `enum`s that are not tagged `#[non_exhaustive]`
     ///
     /// **Why is this bad?** Exhaustive enums are typically fine, but a project which does
-    /// not wish to make a stability commitment around enums may wish to disable them by default.
+    /// not wish to make a stability commitment around exported enums may wish to
+    /// disable them by default.
     ///
     /// **Known problems:** None.
     ///
@@ -28,25 +29,62 @@ declare_clippy_lint! {
     /// enum Foo {
     ///     Bar,
     ///     Baz
-    /// }    /// ```
+    /// }
+    /// ```
     pub EXHAUSTIVE_ENUMS,
     restriction,
-    "default lint description"
+    "detects exported enums that have not been marked #[non_exhaustive]"
 }
 
-declare_lint_pass!(ExhaustiveItems => [EXHAUSTIVE_ENUMS]);
+declare_clippy_lint! {
+    /// **What it does:** Warns on any exported `structs`s that are not tagged `#[non_exhaustive]`
+    ///
+    /// **Why is this bad?** Exhaustive structs are typically fine, but a project which does
+    /// not wish to make a stability commitment around exported structs may wish to
+    /// disable them by default.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust
+    /// struct Foo {
+    ///     bar: u8,
+    ///     baz: String,
+    /// }
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// #[non_exhaustive]
+    /// struct Foo {
+    ///     bar: u8,
+    ///     baz: String,
+    /// }
+    /// ```
+    pub EXHAUSTIVE_STRUCTS,
+    restriction,
+    "detects exported structs that have not been marked #[non_exhaustive]"
+}
+
+declare_lint_pass!(ExhaustiveItems => [EXHAUSTIVE_ENUMS, EXHAUSTIVE_STRUCTS]);
 
 impl LateLintPass<'_> for ExhaustiveItems {
     fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) {
         if_chain! {
-            if let ItemKind::Enum(..) = item.kind;
+            if let ItemKind::Enum(..) | ItemKind::Struct(..) = item.kind;
             if cx.access_levels.is_exported(item.hir_id);
             if !item.attrs.iter().any(|a| a.has_name(sym::non_exhaustive));
             then {
+                let lint = if let ItemKind::Enum(..) = item.kind {
+                    EXHAUSTIVE_ENUMS
+                } else {
+                    EXHAUSTIVE_STRUCTS
+                };
+
                 if let Some(snippet) = snippet_opt(cx, item.span) {
                     span_lint_and_sugg(
                         cx,
-                        EXHAUSTIVE_ENUMS,
+                        lint,
                         item.span,
                         "enums should not be exhaustive",
                         "try adding #[non_exhaustive]",
@@ -56,7 +94,7 @@ impl LateLintPass<'_> for ExhaustiveItems {
                 } else {
                     span_lint_and_help(
                         cx,
-                        EXHAUSTIVE_ENUMS,
+                        lint,
                         item.span,
                         "enums should not be exhaustive",
                         None,

clippy_lints/src/lib.rs

@@ -613,6 +613,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &excessive_bools::FN_PARAMS_EXCESSIVE_BOOLS,
         &excessive_bools::STRUCT_EXCESSIVE_BOOLS,
         &exhaustive_items::EXHAUSTIVE_ENUMS,
+        &exhaustive_items::EXHAUSTIVE_STRUCTS,
         &exit::EXIT,
         &explicit_write::EXPLICIT_WRITE,
         &fallible_impl_from::FALLIBLE_IMPL_FROM,
@@ -1250,6 +1251,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&dbg_macro::DBG_MACRO),
         LintId::of(&else_if_without_else::ELSE_IF_WITHOUT_ELSE),
         LintId::of(&exhaustive_items::EXHAUSTIVE_ENUMS),
+        LintId::of(&exhaustive_items::EXHAUSTIVE_STRUCTS),
         LintId::of(&exit::EXIT),
         LintId::of(&float_literal::LOSSY_FLOAT_LITERAL),
         LintId::of(&implicit_return::IMPLICIT_RETURN),