Declare lint.

Author: xiongmao86

clippy_lints/src/utils/internal_lints.rs

@@ -142,6 +142,12 @@ declare_clippy_lint! {
     "found 'default lint description' in a lint declaration"
 }
 
+declare_clippy_lint! {
+    pub COLLAPSIBLE_SPAN_LINT_CALLS,
+    internal,
+    "found collapsible `span_lint_and_then` calls"
+}
+
 declare_lint_pass!(ClippyLintsInternal => [CLIPPY_LINTS_INTERNAL]);
 
 impl EarlyLintPass for ClippyLintsInternal {
@@ -391,3 +397,11 @@ fn is_trigger_fn(fn_kind: FnKind<'_>) -> bool {
         FnKind::Closure(..) => false,
     }
 }
+
+declare_lint_pass!(CollapsibleCalls => [COLLAPSIBLE_SPAN_LINT_CALLS]);
+
+impl EarlyLintPass for CollapsibleCalls {
+    fn check_expr(&mut self, cx: &EarlyContext<'_>, expr: &ast::Expr) {
+        span_lint_and_help(cx, COLLAPSIBLE_SPAN_LINT_CALLS, expr.span, "lint_message", "help_message");
+    }
+}