Add more regression tests

Author: tesuji

clippy_lints/src/misc_early.rs

@@ -390,10 +390,6 @@ impl EarlyLintPass for MiscEarlyLints {
 
 impl MiscEarlyLints {
     fn check_lit(self, cx: &EarlyContext<'_>, lit: &Lit) {
-        if in_external_macro(cx.sess(), lit.span) {
-            return;
-        }
-
         if let LitKind::Int(value, lit_int_type) = lit.node {
             if let Some(src) = snippet_opt(cx, lit.span) {
                 let suffix = match lit_int_type {

tests/ui/unseparated_prefix_literals.rs

@@ -3,6 +3,10 @@
 #![warn(clippy::unseparated_literal_suffix)]
 #![allow(dead_code)]
 
+macro_rules! lit_from_macro {
+    () => {42};
+}
+
 fn main() {
     let _ok1 = 1234_i32;
     let _ok2 = 1234_isize;
@@ -17,4 +21,8 @@ fn main() {
     let _okf2 = 1_f32;
     let _failf1 = 1.5f32;
     let _failf2 = 1f32;
+
+    // Counter example
+    let _ = line!();
+    let _ = lit_from_macro!();
 }