Fixed macro edge case for semicolon_if_nothing_returned lint

Author: 1c3t3a

clippy_lints/src/semicolon_if_nothing_returned.rs

@@ -1,9 +1,8 @@
-use crate::utils::{match_def_path, paths, span_lint_and_then, sugg};
+use crate::utils::{in_macro, span_lint_and_then, sugg};
 use if_chain::if_chain;
 use rustc_errors::Applicability;
 use rustc_hir::*;
 use rustc_lint::{LateContext, LateLintPass};
-use rustc_middle::ty;
 use rustc_session::{declare_lint_pass, declare_tool_lint};
 
 declare_clippy_lint! {
@@ -20,13 +19,13 @@ declare_clippy_lint! {
     ///
     /// ```rust
     /// fn main() {
-    /// println!("Hello world")
+    ///     println!("Hello world")
     /// }
     /// ```
     /// Use instead:
     /// ```rust
     /// fn main() {
-    /// println!("Hello world");
+    ///     println!("Hello world");
     /// }
     /// ```
     pub SEMICOLON_IF_NOTHING_RETURNED,
@@ -39,10 +38,19 @@ declare_lint_pass!(SemicolonIfNothingReturned => [SEMICOLON_IF_NOTHING_RETURNED]
 impl LateLintPass<'_> for SemicolonIfNothingReturned {
     fn check_block(&mut self, cx: &LateContext<'tcx>, block: &'tcx Block<'tcx>) {
         if_chain! {
+            if !in_macro(block.span);
             if let Some(expr) = block.expr;
             let t_expr = cx.typeck_results().expr_ty(expr);
             if t_expr.is_unit();
             then {
+                match expr.kind {
+                    ExprKind::Loop(..) | 
+                    ExprKind::Match(..) | 
+                    ExprKind::Block(..) | 
+                    ExprKind::If(..) if !in_macro(expr.span) => return,
+                   _ => (),
+                }
+
                 let sugg = sugg::Sugg::hir(cx, &expr, "..");
                 let suggestion = format!("{0};", sugg);
                 span_lint_and_then(

tests/ui/semicolon_if_nothing_returned.rs

@@ -1,4 +1,5 @@
 #![warn(clippy::semicolon_if_nothing_returned)]
+#![feature(label_break_value)]
 
 fn get_unit() {}
 
@@ -11,8 +12,37 @@ fn hello() {
     get_unit()
 }
 
+fn basic101(x: i32) {
+    let y: i32;
+    y = x + 1
+}
+
 // this is fine
 fn print_sum(a: i32, b: i32) {
     println!("{}", a + b);
     assert_eq!(true, false);
 }
+
+fn foo(x: i32) {
+    let y: i32;
+    if x < 1 {
+        y = 4;
+    } else {
+        y = 5;
+    }
+}
+
+fn bar(x: i32) {
+    let y: i32;
+    match x {
+        1 => y = 4,
+        _ => y = 32,
+    }
+}
+
+fn foobar(x: i32) {
+    let y: i32;
+    'label: {
+        y = x + 1;
+    }
+}

tests/ui/semicolon_if_nothing_returned.stderr

@@ -1,5 +1,5 @@
 error: add `;` to terminate block
-  --> $DIR/semicolon_if_nothing_returned.rs:7:5
+  --> $DIR/semicolon_if_nothing_returned.rs:8:5
    |
 LL |     println!("Hello")
    |     ^^^^^^^^^^^^^^^^^
@@ -8,10 +8,16 @@ LL |     println!("Hello")
    = note: this error originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: add `;` to terminate block
-  --> $DIR/semicolon_if_nothing_returned.rs:11:5
+  --> $DIR/semicolon_if_nothing_returned.rs:12:5
    |
 LL |     get_unit()
    |     ^^^^^^^^^^ help: add `;`: `get_unit();`
 
-error: aborting due to 2 previous errors
+error: add `;` to terminate block
+  --> $DIR/semicolon_if_nothing_returned.rs:17:5
+   |
+LL |     y = x + 1
+   |     ^^^^^^^^^ help: add `;`: `y = x + 1;`
+
+error: aborting due to 3 previous errors