Add multiple regression test in name resolution

Local variables and functions or global variables have different
resolution when binded to a variable. This was not covered before, even
though it was handled by the new name resolution. This commit highlight
this behavior from the new name resolution mechanism.

gcc/testsuite/ChangeLog:

	* rust/compile/name_resolution11.rs: New test.
	* rust/compile/name_resolution12.rs: New test.
	* rust/compile/name_resolution13.rs: New test.

Signed-off-by: Pierre-Emmanuel Patry <[email protected]>

gcc/testsuite/rust/compile/name_resolution11.rs

@@ -0,0 +1,7 @@
+// { dg-additional-options "-frust-name-resolution-2.0 -frust-compile-until=lowering" }
+fn foo() {
+    let b = 10;
+    fn bar() {
+        let a = foo;
+    }
+}

gcc/testsuite/rust/compile/name_resolution12.rs

@@ -0,0 +1,10 @@
+// { dg-additional-options "-frust-name-resolution-2.0 -frust-compile-until=lowering" }
+
+const TOTO: i32 = 10;
+
+fn foo() {
+    let b = 10;
+    fn bar() {
+        let e = TOTO;
+    }
+}

gcc/testsuite/rust/compile/name_resolution13.rs

@@ -0,0 +1,9 @@
+// { dg-additional-options "-frust-name-resolution-2.0 -frust-compile-until=lowering" }
+
+fn foo() {
+    let b = 10;
+    fn bar() {
+        let c = b;
+        // { dg-error "cannot find value .b. in this scope .E0425." "" { target *-*-* } .-1 }
+    }
+}