Added checking for hir_dir

Author: Dominic-Moser

clippy_lints/src/always_true_conditions.rs

@@ -1,5 +1,6 @@
 use clippy_utils::diagnostics::span_lint;
-use rustc_hir::{BinOpKind, Expr, ExprKind};
+use rustc_hir::def::Res;
+use rustc_hir::{BinOpKind, Expr, ExprKind, QPath};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_session::declare_lint_pass;
 
@@ -30,18 +31,27 @@ declare_clippy_lint! {
 
 declare_lint_pass!(AlwaysTrueConditions => [ALWAYS_TRUE_CONDITIONS]);
 
-fn context_applicable(expr: &Expr<'_>) -> bool {
+fn context_applicable(expr: &Expr<'_>) -> Option<Res> {
     if let ExprKind::Binary(new_op, new_f, new_l) = expr.kind {
         if new_op.node == BinOpKind::Or {
-            //only continue DOWN if its an or.give me the zuck
             let f = context_applicable(new_f);
             let l = context_applicable(new_l);
-            l && f
+            if l == f { l } else { None }
+        } else if new_op.node == BinOpKind::Ne {
+            find_path(new_f)
         } else {
-            new_op.node == BinOpKind::Ne
+            None
         }
     } else {
-        false
+        None
+    }
+}
+
+fn find_path(expr: &Expr<'_>) -> Option<Res> {
+    if let ExprKind::Path(QPath::Resolved(_, path)) = expr.kind {
+        Some(path.res)
+    } else {
+        None
     }
 }
 
@@ -53,7 +63,7 @@ impl LateLintPass<'_> for AlwaysTrueConditions {
             && let BinOpKind::Or = f_op_kind.node
         {
             let msg = "expression will always be true, did you mean &&?";
-            if context_applicable(f_cond) && context_applicable(l_cond) {
+            if context_applicable(f_cond) == context_applicable(l_cond) {
                 span_lint(cx, ALWAYS_TRUE_CONDITIONS, e.span, msg);
             }
         }

tests/ui/always_true_conditions.rs

@@ -28,9 +28,16 @@ fn foo_s(name: &str) {
     }
 }
 
-fn catch_fails(input: &str) {
+fn catch_or_failure(input: &str) {
     let b = true;
     if b || input != "foo" {
         println!("should not fire!");
     }
 }
+
+fn catch_diff_var_failure(input: &str) {
+    let b = "value";
+    if b != "bar" || input != "foo" {
+        println!("should not fire!");
+    }
+}