add assert(true/false, some message) tests

clippy_lints/src/assertions_on_constants.rs

@@ -7,17 +7,18 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+use crate::consts::{constant, Constant};
 use crate::rustc::hir::{Expr, ExprKind};
 use crate::rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
 use crate::rustc::{declare_tool_lint, lint_array};
 use crate::syntax::ast::LitKind;
-use crate::utils::{is_direct_expn_of, span_lint, span_lint_and_sugg};
+use crate::utils::{is_direct_expn_of, span_help_and_lint};
-use rustc_errors::Applicability;
 use if_chain::if_chain;
 
-/// **What it does:** Check explicit call assert!(true/false)
+/// **What it does:** Check to call assert!(true/false)
 ///
-/// **Why is this bad?** Will be optimized out by the compiler or should probably be replaced by a panic!() or unreachable!()
+/// **Why is this bad?** Will be optimized out by the compiler or should probably be replaced by a
+/// panic!() or unreachable!()
 ///
 /// **Known problems:** None
 ///
@@ -49,22 +50,33 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
         if_chain! {
             if is_direct_expn_of(e.span, "assert").is_some();
             if let ExprKind::Unary(_, ref lit) = e.node;
-            if let ExprKind::Lit(ref inner) = lit.node;
             then {
+                if let ExprKind::Lit(ref inner) = lit.node {
                     match inner.node {
                         LitKind::Bool(true) => {
-                        span_lint(cx, ASSERTIONS_ON_CONSTANTS, e.span,
+                            span_help_and_lint(cx, ASSERTIONS_ON_CONSTANTS, e.span,
-                            "assert!(true) will be optimized out by the compiler");
+                                "assert!(true) will be optimized out by the compiler",
+                                "remove it");
                         },
                         LitKind::Bool(false) => {
-                        span_lint_and_sugg(
+                            span_help_and_lint(
-                            cx,
+                                cx, ASSERTIONS_ON_CONSTANTS, e.span,
-                            ASSERTIONS_ON_CONSTANTS,
-                            e.span,
                                 "assert!(false) should probably be replaced",
-                            "try",
+                                "use panic!() or unreachable!()");
-                            "panic!()".to_string(),
+                        },
-                            Applicability::MachineApplicable);
+                        _ => (),
+                    }
+                } else if let Some(bool_const) = constant(cx, cx.tables, lit) {
+                    match bool_const.0 {
+                        Constant::Bool(true) => {
+                            span_help_and_lint(cx, ASSERTIONS_ON_CONSTANTS, e.span,
+                                "assert!(const: true) will be optimized out by the compiler",
+                                "remove it");
+                        },
+                        Constant::Bool(false) => {
+                            span_help_and_lint(cx, ASSERTIONS_ON_CONSTANTS, e.span,
+                                "assert!(const: false) should probably be replaced",
+                                "use panic!() or unreachable!()");
                         },
                         _ => (),
                     }
@@ -72,3 +84,4 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for AssertionsOnConstants {
             }
         }
     }
+}

tests/ui/assertions_on_constants.rs

@@ -10,4 +10,12 @@
 fn main() {
     assert!(true);
     assert!(false);
+    assert!(true, "true message");
+    assert!(false, "false message");
+
+    const B: bool = true;
+    assert!(B);
+
+    const C: bool = false;
+    assert!(C);
 }

tests/ui/assertions_on_constants.stderr

@@ -5,12 +5,47 @@ LL |     assert!(true);
    |     ^^^^^^^^^^^^^^
    |
    = note: `-D clippy::assertions-on-constants` implied by `-D warnings`
+   = help: remove it
 
 error: assert!(false) should probably be replaced
   --> $DIR/assertions_on_constants.rs:12:5
    |
 LL |     assert!(false);
-   |     ^^^^^^^^^^^^^^^ help: try: `panic!()`
+   |     ^^^^^^^^^^^^^^^
+   |
+   = help: use panic!() or unreachable!()
 
-error: aborting due to 2 previous errors
+error: assert!(true) will be optimized out by the compiler
+  --> $DIR/assertions_on_constants.rs:13:5
+   |
+LL |     assert!(true, "true message");
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: remove it
+
+error: assert!(false) should probably be replaced
+  --> $DIR/assertions_on_constants.rs:14:5
+   |
+LL |     assert!(false, "false message");
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = help: use panic!() or unreachable!()
+
+error: assert!(const: true) will be optimized out by the compiler
+  --> $DIR/assertions_on_constants.rs:17:5
+   |
+LL |     assert!(B);
+   |     ^^^^^^^^^^^
+   |
+   = help: remove it
+
+error: assert!(const: false) should probably be replaced
+  --> $DIR/assertions_on_constants.rs:20:5
+   |
+LL |     assert!(C);
+   |     ^^^^^^^^^^^
+   |
+   = help: use panic!() or unreachable!()
+
+error: aborting due to 6 previous errors