testsuite: adds some tests for ice 4375

Added new tests.

Addresses #4375

gcc/testsuite/ChangeLog:

	* rust/compile/issue-4375-ice-regression.rs: New test.
	* rust/compile/issue-4375-multiple-errors.rs: New test.
	* rust/compile/issue-4375-tuple-pattern.rs: New test.

Signed-off-by: lenny.chiadmi-delage <[email protected]>

Author: Villosse

gcc/testsuite/rust/compile/issue-4375-ice-regression.rs

@@ -0,0 +1,8 @@
+fn get_forty_two() -> i32 {
+    return 42;
+}
+
+fn main() {
+    let myname = get_forty_two() else { return () };
+    // { dg-warning "unused name" "" { target *-*-* } .-1 }
+}

gcc/testsuite/rust/compile/issue-4375-multiple-errors.rs

@@ -0,0 +1,24 @@
+fn foo() -> i32 {
+    1
+}
+fn bar() -> i32 {
+    2
+}
+fn baz() -> i32 {
+    3
+}
+
+fn main() {
+    let a = foo() else {
+        // { dg-warning "unused name" "" { target *-*-* } .-1 }
+        return ();
+    };
+    let b = bar() else {
+        // { dg-warning "unused name" "" { target *-*-* } .-1 }
+        return ();
+    };
+    let c = baz() else {
+        // { dg-warning "unused name" "" { target *-*-* } .-1 }
+        return ();
+    };
+}

gcc/testsuite/rust/compile/issue-4375-tuple-pattern.rs

@@ -0,0 +1,10 @@
+fn get_tuple() -> (i32, i32) {
+    (5, 10)
+}
+
+fn main() {
+    let (x, y) = get_tuple() else {
+        // { dg-warning "unused name" "" { target *-*-* } .-1 }
+        return;
+    };
+}