Rust: Add example from discussion.

Author: geoffw0

rust/ql/test/query-tests/unusedentities/UnreachableCode.expected

@@ -10,17 +10,19 @@
 | unreachable.rs:20:3:20:17 | ExprStmt | This code is never reached. |
 | unreachable.rs:32:3:32:17 | ExprStmt | This code is never reached. |
 | unreachable.rs:39:3:39:17 | ExprStmt | This code is never reached. |
-| unreachable.rs:48:2:48:16 | ExprStmt | This code is never reached. |
-| unreachable.rs:89:3:89:17 | ExprStmt | This code is never reached. |
-| unreachable.rs:97:3:97:17 | ExprStmt | This code is never reached. |
-| unreachable.rs:105:3:107:3 | MatchArm | This code is never reached. |
-| unreachable.rs:108:3:110:3 | MatchArm | This code is never reached. |
-| unreachable.rs:112:2:112:16 | ExprStmt | This code is never reached. |
-| unreachable.rs:115:3:117:3 | MatchArm | This code is never reached. |
-| unreachable.rs:118:3:120:3 | MatchArm | This code is never reached. |
-| unreachable.rs:122:2:122:16 | ExprStmt | This code is never reached. |
-| unreachable.rs:129:3:129:17 | ExprStmt | This code is never reached. |
-| unreachable.rs:138:4:138:18 | ExprStmt | This code is never reached. |
-| unreachable.rs:144:3:144:17 | ExprStmt | This code is never reached. |
+| unreachable.rs:46:6:46:8 | ParenExpr | This code is never reached. |
+| unreachable.rs:48:7:48:10 | ParenExpr | This code is never reached. |
+| unreachable.rs:60:2:60:16 | ExprStmt | This code is never reached. |
+| unreachable.rs:101:3:101:17 | ExprStmt | This code is never reached. |
+| unreachable.rs:109:3:109:17 | ExprStmt | This code is never reached. |
+| unreachable.rs:117:3:119:3 | MatchArm | This code is never reached. |
+| unreachable.rs:120:3:122:3 | MatchArm | This code is never reached. |
+| unreachable.rs:124:2:124:16 | ExprStmt | This code is never reached. |
+| unreachable.rs:127:3:129:3 | MatchArm | This code is never reached. |
+| unreachable.rs:130:3:132:3 | MatchArm | This code is never reached. |
+| unreachable.rs:134:2:134:16 | ExprStmt | This code is never reached. |
+| unreachable.rs:141:3:141:17 | ExprStmt | This code is never reached. |
 | unreachable.rs:150:4:150:18 | ExprStmt | This code is never reached. |
-| unreachable.rs:153:2:153:16 | ExprStmt | This code is never reached. |
+| unreachable.rs:156:3:156:17 | ExprStmt | This code is never reached. |
+| unreachable.rs:162:4:162:18 | ExprStmt | This code is never reached. |
+| unreachable.rs:165:2:165:16 | ExprStmt | This code is never reached. |

rust/ql/test/query-tests/unusedentities/unreachable.rs

@@ -40,6 +40,18 @@ fn unreachable_if() {
 	}
 	do_something();
 
+	if cond() {
+		bool x = cond();
+
+		if (x) { // SPURIOUS: unreachable
+			do_something();
+			if (!x) { // SPURIOUS: unreachable
+				do_something(); // BAD: unreachable code [NOT DETECTED]
+			}
+			do_something();
+		}
+	}
+
 	if cond() {
 		return;
 	} else {