Deny imports after non-item statements.

Author: eddyb

src/librustc/diagnostics.rs

@@ -52,6 +52,7 @@ register_diagnostics! {
     E0140,
     E0152,
     E0153,
+    E0154,
     E0157,
     E0158,
     E0161,

src/librustc_resolve/lib.rs

@@ -3505,6 +3505,26 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             }
         }
 
+        // Check for imports appearing after non-item statements.
+        let mut found_non_item = false;
+        for statement in block.stmts.iter() {
+            if let ast::StmtDecl(ref declaration, _) = statement.node {
+                if let ast::DeclItem(ref i) = declaration.node {
+                    match i.node {
+                        ItemExternCrate(_) | ItemUse(_) if found_non_item => {
+                            span_err!(self.session, i.span, E0154,
+                                "imports are not allowed after non-item statements");
+                        }
+                        _ => {}
+                    }
+                } else {
+                    found_non_item = true
+                }
+            } else {
+                found_non_item = true;
+            }
+        }
+
         // Descend into the block.
         visit::walk_block(self, block);
 

src/test/compile-fail/blind-item-block-middle.rs

@@ -14,4 +14,5 @@ fn main() {
     let bar = 5;
     //~^ ERROR declaration of `bar` shadows an enum variant or unit-like struct in scope
     use foo::bar;
+    //~^ ERROR imports are not allowed after non-item statements
 }

src/test/run-pass/blind-item-local-shadow.rs renamed to src/test/compile-fail/blind-item-local-shadow.rs

@@ -9,11 +9,12 @@
 // except according to those terms.
 
 mod bar {
-    pub fn foo() -> uint { 42 }
+    pub fn foo() -> bool { true }
 }
 
 fn main() {
-    let foo = |&:| 5u;
+    let foo = |&:| false;
     use bar::foo;
-    assert_eq!(foo(), 5u);
+    //~^ ERROR imports are not allowed after non-item statements
+    assert_eq!(foo(), false);
 }