Add TestCases::full_build() to force full builds.

src/cargo.rs

@@ -80,7 +80,7 @@ pub(crate) fn build_dependencies(project: &mut Project) -> Result<()> {
 
     let mut command = cargo(project);
     command
-        .arg(if project.has_pass { "build" } else { "check" })
+        .arg(if project.full_build { "build" } else { "check" })
         .args(target())
         .arg("--bin")
         .arg(&project.name)
@@ -114,7 +114,7 @@ pub(crate) fn build_test(project: &Project, name: &Name) -> Result<Output> {
         .status();
 
     cargo(project)
-        .arg(if project.has_pass { "build" } else { "check" })
+        .arg(if project.full_build { "build" } else { "check" })
         .args(target())
         .arg("--bin")
         .arg(name)
@@ -137,7 +137,7 @@ pub(crate) fn build_all_tests(project: &Project) -> Result<Output> {
         .status();
 
     cargo(project)
-        .arg(if project.has_pass { "build" } else { "check" })
+        .arg(if project.full_build { "build" } else { "check" })
         .args(target())
         .arg("--bins")
         .args(features(project))

src/lib.rs

@@ -294,6 +294,7 @@ pub struct TestCases {
 #[derive(Debug)]
 struct Runner {
     tests: Vec<Test>,
+    full_build: bool,
 }
 
 #[derive(Clone, Debug)]
@@ -312,23 +313,44 @@ impl TestCases {
     #[allow(clippy::new_without_default)]
     pub fn new() -> Self {
         TestCases {
-            runner: RefCell::new(Runner { tests: Vec::new() }),
+            runner: RefCell::new(Runner {
+                tests: Vec::new(),
+                full_build: false,
+            }),
         }
     }
 
+    /// Add one or more source files containing pass tests.
+    ///
+    /// You can use a [`glob`][glob::glob] patterns add multiple source files at once.
+    ///
+    /// Each source file must have a `main` function, and the test is considered to suceed if the `main` function does not panic.
     pub fn pass<P: AsRef<Path>>(&self, path: P) {
         self.runner.borrow_mut().tests.push(Test {
             path: path.as_ref().to_owned(),
             expected: Expected::Pass,
         });
     }
 
+    /// Add one or more source files containing compile-fail tests.
+    ///
+    /// You can use a [`glob`][glob::glob] patterns add multiple source files at once.
     pub fn compile_fail<P: AsRef<Path>>(&self, path: P) {
         self.runner.borrow_mut().tests.push(Test {
             path: path.as_ref().to_owned(),
             expected: Expected::CompileFail,
         });
     }
+
+    /// Enable or disable full builds of the test cases.
+    ///
+    /// To save time, `trybuild` runs `cargo check` instead of `cargo build` if there are no [`pass()`][Self::pass] tests.
+    /// However, some build failures (like assertions in const context) do not currently show up with `cargo check`.
+    ///
+    /// You can force `trybuild` to run a full build as a work-around.
+    pub fn full_build(&self, full: bool) {
+        self.runner.borrow_mut().full_build = full;
+    }
 }
 
 impl RefUnwindSafe for TestCases {}

src/run.rs

@@ -25,8 +25,9 @@ pub(crate) struct Project {
     pub target_dir: Directory,
     pub name: String,
     update: Update,
-    pub has_pass: bool,
+    has_pass: bool,
     has_compile_fail: bool,
+    pub full_build: bool,
     pub features: Option<Vec<String>>,
     pub workspace: Directory,
     pub path_dependencies: Vec<PathDependency>,
@@ -172,6 +173,7 @@ impl Runner {
             update: Update::env()?,
             has_pass,
             has_compile_fail,
+            full_build: self.full_build || has_pass,
             features,
             workspace,
             path_dependencies,

tests/test.rs

@@ -20,3 +20,10 @@ fn test() {
     t.compile_fail("tests/ui/compile-fail-2.rs");
     t.compile_fail("tests/ui/compile-fail-3.rs");
 }
+
+#[test]
+fn test_full_build() {
+    let t = trybuild::TestCases::new();
+    t.compile_fail("tests/ui/compile-fail-const-assert.rs");
+    t.full_build(true);
+}

tests/ui/compile-fail-const-assert.rs

@@ -0,0 +1,3 @@
+fn main() {
+    const { assert!(false) };
+}

tests/ui/compile-fail-const-assert.stderr

@@ -0,0 +1,13 @@
+error[E0080]: evaluation of `main::{constant#0}` failed
+ --> tests/ui/compile-fail-const-assert.rs:2:13
+  |
+2 |     const { assert!(false) };
+  |             ^^^^^^^^^^^^^^ the evaluated program panicked at 'assertion failed: false', $DIR/tests/ui/compile-fail-const-assert.rs:2:13
+  |
+  = note: this error originates in the macro `assert` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+note: erroneous constant encountered
+ --> tests/ui/compile-fail-const-assert.rs:2:5
+  |
+2 |     const { assert!(false) };
+  |     ^^^^^^^^^^^^^^^^^^^^^^^^