Auto merge of #29402 - sanxiyn:if-let, r=steveklabnik

Author: bors

src/librustc_lint/types.rs

@@ -659,18 +659,15 @@ impl LateLintPass for ImproperCTypes {
             }
         }
 
-        match it.node {
-            hir::ItemForeignMod(ref nmod)
-                if nmod.abi != abi::RustIntrinsic &&
-                   nmod.abi != abi::PlatformIntrinsic => {
+        if let hir::ItemForeignMod(ref nmod) = it.node {
+            if nmod.abi != abi::RustIntrinsic && nmod.abi != abi::PlatformIntrinsic {
                 for ni in &nmod.items {
                     match ni.node {
                         hir::ForeignItemFn(ref decl, _) => check_foreign_fn(cx, &**decl),
                         hir::ForeignItemStatic(ref t, _) => check_ty(cx, &**t)
                     }
                 }
             }
-            _ => (),
         }
     }
 }

src/librustc_lint/unused.rs

@@ -220,15 +220,11 @@ impl LintPass for PathStatements {
 
 impl LateLintPass for PathStatements {
     fn check_stmt(&mut self, cx: &LateContext, s: &hir::Stmt) {
-        match s.node {
-            hir::StmtSemi(ref expr, _) => {
-                match expr.node {
-                    hir::ExprPath(..) => cx.span_lint(PATH_STATEMENTS, s.span,
-                                                      "path statement with no effect"),
-                    _ => ()
-                }
+        if let hir::StmtSemi(ref expr, _) = s.node {
+            if let hir::ExprPath(..) = expr.node {
+                cx.span_lint(PATH_STATEMENTS, s.span,
+                             "path statement with no effect");
             }
-            _ => ()
         }
     }
 }