diff --git a/COVERAGE.md b/COVERAGE.md
new file mode 100644
index 0000000000..4c26787696
--- /dev/null
+++ b/COVERAGE.md
@@ -0,0 +1,35 @@
+# Code Coverage
+
+## Quick Start
+
+```bash
+# Install cargo-llvm-cov (first time only)
+cargo install cargo-llvm-cov
+
+# Run coverage and open HTML report
+cargo llvm-cov --html --open
+
+# Run coverage for specific tests
+cargo llvm-cov --html --open -- test_name
+```
+
+## Reports
+
+HTML report location: `target/llvm-cov/html/index.html`
+
+## Coverage Summary
+
+View text summary:
+```bash
+cargo llvm-cov report --summary-only
+```
+
+## Notes
+
+- Trybuild compile-time tests do not appear in coverage reports (they verify compile errors, not runtime behavior)
+- Coverage measures runtime test execution only
+- Current project coverage: ~74% lines, ~68% functions
+
+## Reference
+
+- [cargo-llvm-cov documentation](https://github.com/taiki-e/cargo-llvm-cov)
diff --git a/Cargo.lock b/Cargo.lock
index 9447fc2fec..4e904f9828 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1336,12 +1336,6 @@ dependencies = [
  "allocator-api2",
 ]
 
-[[package]]
-name = "hashbrown"
-version = "0.15.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "84b26c544d002229e640969970a2e74021aadf6e2f96372b9c58eff97de08eb3"
-
 [[package]]
 name = "hashbrown"
 version = "0.16.1"
@@ -1647,7 +1641,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4b0f83760fb341a774ed326568e19f5a863af4a952def8c39f9ab92fd95b88e5"
 dependencies = [
  "equivalent",
- "hashbrown 0.15.3",
+ "hashbrown 0.16.1",
 ]
 
 [[package]]
@@ -3375,6 +3369,15 @@ dependencies = [
  "serde_core",
 ]
 
+[[package]]
+name = "serde_spanned"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8bbf91e5a4d6315eee45e704372590b30e260ee83af6639d64557f51b067776"
+dependencies = [
+ "serde_core",
+]
+
 [[package]]
 name = "serde_urlencoded"
 version = "0.7.1"
@@ -3648,6 +3651,12 @@ version = "0.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7b2093cf4c8eb1e67749a6762251bc9cd836b6fc171623bd0a9d324d37af2417"
 
+[[package]]
+name = "target-triple"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "591ef38edfb78ca4771ee32cf494cb8771944bee237a9b91fc9c1424ac4b777b"
+
 [[package]]
 name = "tempfile"
 version = "3.21.0"
@@ -3864,6 +3873,45 @@ dependencies = [
  "tokio",
 ]
 
+[[package]]
+name = "toml"
+version = "0.9.11+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f3afc9a848309fe1aaffaed6e1546a7a14de1f935dc9d89d32afd9a44bab7c46"
+dependencies = [
+ "indexmap",
+ "serde_core",
+ "serde_spanned",
+ "toml_datetime",
+ "toml_parser",
+ "toml_writer",
+ "winnow",
+]
+
+[[package]]
+name = "toml_datetime"
+version = "0.7.5+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "92e1cfed4a3038bc5a127e35a2d360f145e1f4b971b551a2ba5fd7aedf7e1347"
+dependencies = [
+ "serde_core",
+]
+
+[[package]]
+name = "toml_parser"
+version = "1.0.6+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a3198b4b0a8e11f09dd03e133c0280504d0801269e9afa46362ffde1cbeebf44"
+dependencies = [
+ "winnow",
+]
+
+[[package]]
+name = "toml_writer"
+version = "1.0.6+spec-1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab16f14aed21ee8bfd8ec22513f7287cd4a91aa92e44edfe2c17ddd004e92607"
+
 [[package]]
 name = "tower"
 version = "0.5.2"
@@ -3998,6 +4046,21 @@ version = "0.2.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 
+[[package]]
+name = "trybuild"
+version = "1.0.114"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3e17e807bff86d2a06b52bca4276746584a78375055b6e45843925ce2802b335"
+dependencies = [
+ "glob",
+ "serde",
+ "serde_derive",
+ "serde_json",
+ "target-triple",
+ "termcolor",
+ "toml",
+]
+
 [[package]]
 name = "twox-hash"
 version = "2.1.2"
@@ -4256,6 +4319,7 @@ dependencies = [
  "tokio",
  "tracing",
  "tracing-test",
+ "trybuild",
  "ua-parser",
  "unicode-segmentation",
  "url",
@@ -4815,6 +4879,12 @@ version = "0.53.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "271414315aff87387382ec3d271b52d7ae78726f5d44ac98b4f4030c91880486"
 
+[[package]]
+name = "winnow"
+version = "0.7.14"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a5364e9d77fcdeeaa6062ced926ee3381faa2ee02d3eb83a5c27a8825540829"
+
 [[package]]
 name = "winsafe"
 version = "0.0.19"
diff --git a/Cargo.toml b/Cargo.toml
index dc6f403fdb..c8f1e53338 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -263,6 +263,7 @@ regex = { version = "1", default-features = false, features = ["std", "perf", "u
 paste = { version = "1", default-features = false }
 proptest = { version = "1" }
 proptest-derive = { version = "0.6" }
+trybuild = "1.0.114"
 
 [build-dependencies]
 lalrpop = { version = "0.22", default-features = false }
diff --git a/scripts/check_deny.sh b/scripts/check_deny.sh
index 0a5825c22f..842a1c8fbd 100755
--- a/scripts/check_deny.sh
+++ b/scripts/check_deny.sh
@@ -1,8 +1,8 @@
 #!/bin/bash
 
-if ! cargo install --list | grep -q "cargo-deny v0.18.3"; then
+if ! cargo install --list | grep -q "cargo-deny v0.19.0"; then
     echo "Install cargo-deny"
-    cargo install cargo-deny --version 0.18.3 --force --locked
+    cargo install cargo-deny --version 0.19.0 --force --locked
 fi
 
 echo "Check deny"
diff --git a/src/compiler/function.rs b/src/compiler/function.rs
index 0b416fd740..035bcec2f2 100644
--- a/src/compiler/function.rs
+++ b/src/compiler/function.rs
@@ -87,7 +87,55 @@ pub struct Example {
 /// Macro to create an `Example` with automatic source location tracking
 /// Accepts fields in any order: title, source, result
 /// Optional fields added to `Example` shouldn't be required to be added for the macro to work,
-/// mainting backwards compatibility
+/// maintaining backwards compatibility
+///
+/// # Examples
+///
+/// Valid usage:
+/// ```
+/// use vrl::example;
+///
+/// let ex = example! {
+///     title: "test",
+///     source: "code",
+///     result: Ok("output"),
+/// };
+/// ```
+///
+/// Missing required field should fail:
+/// ```compile_fail
+/// use vrl::example;
+///
+/// let ex = example! {
+///     title: "test",
+///     source: "code",
+///     // missing result field
+/// };
+/// ```
+///
+/// Duplicate field should fail:
+/// ```compile_fail
+/// use vrl::example;
+///
+/// let ex = example! {
+///     title: "test",
+///     source: "code",
+///     result: Ok("output"),
+///     title: "duplicate",
+/// };
+/// ```
+///
+/// Unknown field should fail:
+/// ```compile_fail
+/// use vrl::example;
+///
+/// let ex = example! {
+///     title: "test",
+///     source: "code",
+///     result: Ok("output"),
+///     unknown_field: "value",
+/// };
+/// ```
 #[macro_export]
 macro_rules! example {
     // Entry point - delegate to internal parser with empty state
@@ -97,6 +145,21 @@ macro_rules! example {
         $crate::example!(@internal [] [] [] [$($field: $value,)*])
     };
 
+    // Error: duplicate title field
+    (@internal [$title:expr] [$($source:tt)*] [$($result:tt)*] [title: $t:expr, $($rest:tt)*]) => {
+        compile_error!("duplicate 'title' field in example! macro")
+    };
+
+    // Error: duplicate source field
+    (@internal [$($title:tt)*] [$source:expr] [$($result:tt)*] [source: $s:expr, $($rest:tt)*]) => {
+        compile_error!("duplicate 'source' field in example! macro")
+    };
+
+    // Error: duplicate result field
+    (@internal [$($title:tt)*] [$($source:tt)*] [$result:expr] [result: $r:expr, $($rest:tt)*]) => {
+        compile_error!("duplicate 'result' field in example! macro")
+    };
+
     // Parse title field
     (@internal [$($title:tt)*] [$($source:tt)*] [$($result:tt)*] [title: $t:expr, $($rest:tt)*]) => {
         $crate::example!(@internal [$t] [$($source)*] [$($result)*] [$($rest)*])
@@ -714,4 +777,27 @@ mod tests {
         assert_eq!(ex3.source, "code3");
         assert_eq!(ex3.result, Err("error3"));
     }
+
+    #[test]
+    fn test_example_macro_trailing_commas() {
+        // Test with trailing comma
+        let ex_with_comma = example! {
+            title: "test",
+            source: "code",
+            result: Ok("ok"),
+        };
+        assert_eq!(ex_with_comma.title, "test");
+        assert_eq!(ex_with_comma.source, "code");
+        assert_eq!(ex_with_comma.result, Ok("ok"));
+
+        // Test without trailing comma
+        let ex_no_comma = example! {
+            title: "test",
+            source: "code",
+            result: Ok("ok")
+        };
+        assert_eq!(ex_no_comma.title, "test");
+        assert_eq!(ex_no_comma.source, "code");
+        assert_eq!(ex_no_comma.result, Ok("ok"));
+    }
 }
diff --git a/src/stdlib/parse_klog.rs b/src/stdlib/parse_klog.rs
index c1c86768d1..841f0b3b5f 100644
--- a/src/stdlib/parse_klog.rs
+++ b/src/stdlib/parse_klog.rs
@@ -89,7 +89,7 @@ impl Function for ParseKlog {
                     "level": "info",
                     "line": 70,
                     "message": "hello from klog",
-                    "timestamp": "2025-05-05T17:59:40.692994Z"
+                    "timestamp": "{CURRENT_YEAR}-05-05T17:59:40.692994Z"
                 }"#}),
         }]
     }
diff --git a/src/stdlib/parse_linux_authorization.rs b/src/stdlib/parse_linux_authorization.rs
index 7caef05741..009d312b5c 100644
--- a/src/stdlib/parse_linux_authorization.rs
+++ b/src/stdlib/parse_linux_authorization.rs
@@ -27,7 +27,7 @@ impl Function for ParseLinuxAuthorization {
                 "hostname": "localhost",
                 "message": "Accepted publickey for eng from 10.1.1.1 port 8888 ssh2: RSA SHA256:foobar",
                 "procid": 1111,
-                "timestamp": "2025-03-23T01:49:58Z"
+                "timestamp": "{CURRENT_YEAR}-03-23T01:49:58Z"
             }"#}),
         }]
     }
diff --git a/src/test/mod.rs b/src/test/mod.rs
index ceab7fdb8f..955bd5108a 100644
--- a/src/test/mod.rs
+++ b/src/test/mod.rs
@@ -208,7 +208,7 @@ fn process_result(
             let got_value = vrl_value_to_json_value(got);
             let mut failed = false;
 
-            let want = test.result.clone();
+            let want = replace_current_year_placeholder(test.result.clone());
             let want_value = if want.starts_with("r'") && want.ends_with('\'') {
                 match regex::Regex::new(&want[2..want.len() - 1].replace("\\'", "'")) {
                     Ok(regex) => regex.to_string().into(),
@@ -257,7 +257,7 @@ fn process_result(
         Err(err) => {
             let mut failed = false;
             let got = err.to_string().trim().to_owned();
-            let want = test.result.clone().trim().to_owned();
+            let want = replace_current_year_placeholder(test.result.clone().trim().to_owned());
 
             if (test.result_approx && compare_partial_diagnostic(&got, &want)) || got == want {
                 println!("{}{}", Colour::Green.bold().paint("OK"), timings);
@@ -319,7 +319,7 @@ fn process_compilation_diagnostics(
     let got = formatter.to_string();
     let got = got.trim();
 
-    let want = test.result.clone();
+    let want = replace_current_year_placeholder(test.result.clone());
     let want = want.trim();
 
     if (test.result_approx && compare_partial_diagnostic(got, want)) || got == want {
@@ -404,6 +404,11 @@ fn print_result(
     std::process::exit(code)
 }
 
+fn replace_current_year_placeholder(input: String) -> String {
+    let current_year = Utc::now().format("%Y").to_string();
+    input.replace("{CURRENT_YEAR}", &current_year)
+}
+
 fn compare_partial_diagnostic(got: &str, want: &str) -> bool {
     got.lines()
         .filter(|line| line.trim().starts_with("error[E"))
diff --git a/tests/README.md b/tests/README.md
new file mode 100644
index 0000000000..de766bbaaf
--- /dev/null
+++ b/tests/README.md
@@ -0,0 +1,46 @@
+# VRL Tests
+
+Some tests are organized to mirror source code structure:
+```
+src/compiler/function.rs  →  tests/compiler/function/*/
+src/parser/lex.rs  →  tests/parser/lex/*/
+```
+
+## Trybuild Tests (Compile-Time)
+
+Trybuild tests verify code fails to compile with correct error messages. Defined in `tests/trybuild.rs`.
+
+### Quick Workflow
+
+1. **Create test file**: `tests/compiler/function/example/my_test.rs`
+2. **Run tests**: `cargo test --test trybuild` (creates `wip/my_test.stderr`)
+3. **Review error**: `cat wip/my_test.stderr`
+4. **Accept (bless)**: `mv wip/my_test.stderr tests/compiler/function/example/`
+5. **Add to suite**: Edit `tests/trybuild.rs`, add `t.compile_fail("tests/.../my_test.rs")`
+6. **Commit both files**: `.rs` and `.stderr` files together
+
+### Important: Commit .stderr Files
+
+**Always commit `.stderr` files** - they define expected error messages and enable regression detection.
+
+### Update Error Messages
+
+```bash
+TRYBUILD=overwrite cargo test --test trybuild
+git diff tests/  # Review changes
+```
+
+## Commands
+
+```bash
+cargo test                                          # All tests
+cargo test --test trybuild                          # Trybuild only
+cargo test --test trybuild compiler_function_example # Specific test
+```
+
+Note: `trybuild` tests do not show up in code coverage reports.
+
+## Reference
+
+- [trybuild docs](https://docs.rs/trybuild/)
+- [Rust testing guide](https://doc.rust-lang.org/book/ch11-00-testing.html)
diff --git a/tests/compiler/function/example/duplicate_result.rs b/tests/compiler/function/example/duplicate_result.rs
new file mode 100644
index 0000000000..ae3371651c
--- /dev/null
+++ b/tests/compiler/function/example/duplicate_result.rs
@@ -0,0 +1,10 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        title: "test",
+        source: "code",
+        result: Ok("output"),
+        result: Err("duplicate"),
+    };
+}
diff --git a/tests/compiler/function/example/duplicate_result.stderr b/tests/compiler/function/example/duplicate_result.stderr
new file mode 100644
index 0000000000..92c8e7e535
--- /dev/null
+++ b/tests/compiler/function/example/duplicate_result.stderr
@@ -0,0 +1,13 @@
+error: duplicate 'result' field in example! macro
+ --> tests/compiler/function/example/duplicate_result.rs:4:15
+  |
+4 |       let _ex = example! {
+  |  _______________^
+5 | |         title: "test",
+6 | |         source: "code",
+7 | |         result: Ok("output"),
+8 | |         result: Err("duplicate"),
+9 | |     };
+  | |_____^
+  |
+  = note: this error originates in the macro `$crate::example` which comes from the expansion of the macro `example` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/compiler/function/example/duplicate_source.rs b/tests/compiler/function/example/duplicate_source.rs
new file mode 100644
index 0000000000..329503a1c2
--- /dev/null
+++ b/tests/compiler/function/example/duplicate_source.rs
@@ -0,0 +1,10 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        title: "test",
+        source: "code",
+        result: Ok("output"),
+        source: "duplicate",
+    };
+}
diff --git a/tests/compiler/function/example/duplicate_source.stderr b/tests/compiler/function/example/duplicate_source.stderr
new file mode 100644
index 0000000000..a62bcdabe0
--- /dev/null
+++ b/tests/compiler/function/example/duplicate_source.stderr
@@ -0,0 +1,13 @@
+error: duplicate 'source' field in example! macro
+ --> tests/compiler/function/example/duplicate_source.rs:4:15
+  |
+4 |       let _ex = example! {
+  |  _______________^
+5 | |         title: "test",
+6 | |         source: "code",
+7 | |         result: Ok("output"),
+8 | |         source: "duplicate",
+9 | |     };
+  | |_____^
+  |
+  = note: this error originates in the macro `$crate::example` which comes from the expansion of the macro `example` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/compiler/function/example/duplicate_title.rs b/tests/compiler/function/example/duplicate_title.rs
new file mode 100644
index 0000000000..910c8de49c
--- /dev/null
+++ b/tests/compiler/function/example/duplicate_title.rs
@@ -0,0 +1,10 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        title: "test",
+        source: "code",
+        result: Ok("output"),
+        title: "duplicate",
+    };
+}
diff --git a/tests/compiler/function/example/duplicate_title.stderr b/tests/compiler/function/example/duplicate_title.stderr
new file mode 100644
index 0000000000..11fd7abab6
--- /dev/null
+++ b/tests/compiler/function/example/duplicate_title.stderr
@@ -0,0 +1,13 @@
+error: duplicate 'title' field in example! macro
+ --> tests/compiler/function/example/duplicate_title.rs:4:15
+  |
+4 |       let _ex = example! {
+  |  _______________^
+5 | |         title: "test",
+6 | |         source: "code",
+7 | |         result: Ok("output"),
+8 | |         title: "duplicate",
+9 | |     };
+  | |_____^
+  |
+  = note: this error originates in the macro `$crate::example` which comes from the expansion of the macro `example` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/compiler/function/example/missing_result.rs b/tests/compiler/function/example/missing_result.rs
new file mode 100644
index 0000000000..48935f1235
--- /dev/null
+++ b/tests/compiler/function/example/missing_result.rs
@@ -0,0 +1,8 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        title: "test",
+        source: "code",
+    };
+}
diff --git a/tests/compiler/function/example/missing_result.stderr b/tests/compiler/function/example/missing_result.stderr
new file mode 100644
index 0000000000..ec3c48c884
--- /dev/null
+++ b/tests/compiler/function/example/missing_result.stderr
@@ -0,0 +1,16 @@
+error: no rules expected `]`
+ --> tests/compiler/function/example/missing_result.rs:4:15
+  |
+4 |       let _ex = example! {
+  |  _______________^
+5 | |         title: "test",
+6 | |         source: "code",
+7 | |     };
+  | |_____^ no rules expected this token in macro call
+  |
+note: while trying to match `title`
+ --> src/compiler/function.rs
+  |
+  |     (@internal [$title:expr] [$($source:tt)*] [$($result:tt)*] [title: $t:expr, $($rest:tt)*]) => {
+  |                                                                 ^^^^^
+  = note: this error originates in the macro `$crate::example` which comes from the expansion of the macro `example` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/compiler/function/example/missing_source.rs b/tests/compiler/function/example/missing_source.rs
new file mode 100644
index 0000000000..a555d79cbc
--- /dev/null
+++ b/tests/compiler/function/example/missing_source.rs
@@ -0,0 +1,8 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        title: "test",
+        result: Ok("output"),
+    };
+}
diff --git a/tests/compiler/function/example/missing_source.stderr b/tests/compiler/function/example/missing_source.stderr
new file mode 100644
index 0000000000..cc6ee25286
--- /dev/null
+++ b/tests/compiler/function/example/missing_source.stderr
@@ -0,0 +1,16 @@
+error: no rules expected `]`
+ --> tests/compiler/function/example/missing_source.rs:4:15
+  |
+4 |       let _ex = example! {
+  |  _______________^
+5 | |         title: "test",
+6 | |         result: Ok("output"),
+7 | |     };
+  | |_____^ no rules expected this token in macro call
+  |
+note: while trying to match `title`
+ --> src/compiler/function.rs
+  |
+  |     (@internal [$title:expr] [$($source:tt)*] [$($result:tt)*] [title: $t:expr, $($rest:tt)*]) => {
+  |                                                                 ^^^^^
+  = note: this error originates in the macro `$crate::example` which comes from the expansion of the macro `example` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/compiler/function/example/missing_title.rs b/tests/compiler/function/example/missing_title.rs
new file mode 100644
index 0000000000..eae56253dc
--- /dev/null
+++ b/tests/compiler/function/example/missing_title.rs
@@ -0,0 +1,8 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        source: "code",
+        result: Ok("output"),
+    };
+}
diff --git a/tests/compiler/function/example/missing_title.stderr b/tests/compiler/function/example/missing_title.stderr
new file mode 100644
index 0000000000..0bb8b05d07
--- /dev/null
+++ b/tests/compiler/function/example/missing_title.stderr
@@ -0,0 +1,16 @@
+error: no rules expected `]`
+ --> tests/compiler/function/example/missing_title.rs:4:15
+  |
+4 |       let _ex = example! {
+  |  _______________^
+5 | |         source: "code",
+6 | |         result: Ok("output"),
+7 | |     };
+  | |_____^ no rules expected this token in macro call
+  |
+note: while trying to match `source`
+ --> src/compiler/function.rs
+  |
+  |     (@internal [$($title:tt)*] [$source:expr] [$($result:tt)*] [source: $s:expr, $($rest:tt)*]) => {
+  |                                                                 ^^^^^^
+  = note: this error originates in the macro `$crate::example` which comes from the expansion of the macro `example` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/compiler/function/example/pass.rs b/tests/compiler/function/example/pass.rs
new file mode 100644
index 0000000000..4cc927de3a
--- /dev/null
+++ b/tests/compiler/function/example/pass.rs
@@ -0,0 +1,9 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        title: "test",
+        source: "code",
+        result: Ok("output"),
+    };
+}
diff --git a/tests/compiler/function/example/unknown_field.rs b/tests/compiler/function/example/unknown_field.rs
new file mode 100644
index 0000000000..a4b7f33113
--- /dev/null
+++ b/tests/compiler/function/example/unknown_field.rs
@@ -0,0 +1,10 @@
+use vrl::example;
+
+fn main() {
+    let _ex = example! {
+        title: "test",
+        source: "code",
+        result: Ok("output"),
+        unknown_field: "value",
+    };
+}
diff --git a/tests/compiler/function/example/unknown_field.stderr b/tests/compiler/function/example/unknown_field.stderr
new file mode 100644
index 0000000000..8f33b2e358
--- /dev/null
+++ b/tests/compiler/function/example/unknown_field.stderr
@@ -0,0 +1,18 @@
+error: no rules expected identifier `unknown_field`
+ --> tests/compiler/function/example/unknown_field.rs:4:15
+  |
+4 |       let _ex = example! {
+  |  _______________^
+5 | |         title: "test",
+6 | |         source: "code",
+7 | |         result: Ok("output"),
+8 | |         unknown_field: "value",
+9 | |     };
+  | |_____^ no rules expected this token in macro call
+  |
+note: while trying to match `title`
+ --> src/compiler/function.rs
+  |
+  |     (@internal [$title:expr] [$($source:tt)*] [$($result:tt)*] [title: $t:expr, $($rest:tt)*]) => {
+  |                                                                 ^^^^^
+  = note: this error originates in the macro `example` (in Nightly builds, run with -Z macro-backtrace for more info)
diff --git a/tests/trybuild.rs b/tests/trybuild.rs
new file mode 100644
index 0000000000..5a32f5ab86
--- /dev/null
+++ b/tests/trybuild.rs
@@ -0,0 +1,53 @@
+//! Compile-time tests using trybuild.
+//!
+//! These tests verify that macros and other compile-time constructs correctly
+//! reject invalid usage with appropriate error messages.
+//!
+//! # Organization
+//!
+//! Test files are organized to mirror the source code structure:
+//! - `src/compiler/function.rs` → `tests/compiler/function/*/`
+//! - `src/parser/foo.rs` → `tests/parser/foo/*/`
+//!
+//! # Adding New Tests
+//!
+//! 1. Create test files in the appropriate directory matching the source structure
+//! 2. Add a new test function following the naming pattern: `{module}_{submodule}_{feature}`
+//! 3. Use `t.pass()` for tests that should compile successfully
+//! 4. Use `t.compile_fail()` for tests that should fail with specific error messages
+
+/// Tests for the example! macro defined in src/compiler/function.rs
+///
+/// The example! macro accepts fields in any order and validates:
+/// - All required fields are present (title, source, result)
+/// - No duplicate fields
+/// - No unknown fields
+#[test]
+fn compiler_function_example() {
+    let t = trybuild::TestCases::new();
+
+    // Valid usage
+    t.pass("tests/compiler/function/example/pass.rs");
+
+    // Duplicate field errors
+    t.compile_fail("tests/compiler/function/example/duplicate_title.rs");
+    t.compile_fail("tests/compiler/function/example/duplicate_source.rs");
+    t.compile_fail("tests/compiler/function/example/duplicate_result.rs");
+
+    // Missing field errors
+    t.compile_fail("tests/compiler/function/example/missing_title.rs");
+    t.compile_fail("tests/compiler/function/example/missing_source.rs");
+    t.compile_fail("tests/compiler/function/example/missing_result.rs");
+
+    // Unknown field errors
+    t.compile_fail("tests/compiler/function/example/unknown_field.rs");
+}
+
+// Add more test functions here as needed:
+//
+// #[test]
+// fn parser_something() {
+//     let t = trybuild::TestCases::new();
+//     t.pass("tests/parser/something/pass.rs");
+//     t.compile_fail("tests/parser/something/fail.rs");
+// }