4 files changed, 322 insertions, 0 deletions

diff --git a/crates/ide/src/diagnostics/inactive_code.rs b/crates/ide/src/diagnostics/inactive_code.rs
new file mode 100644
index 000000000..afe333204
--- /dev/null
+++ b/crates/ide/src/diagnostics/inactive_code.rs
@@ -0,0 +1,117 @@
+use cfg::DnfExpr;
+use stdx::format_to;
+
+use crate::{
+    diagnostics::{Diagnostic, DiagnosticsContext},
+    Severity,
+};
+
+// Diagnostic: inactive-code
+//
+// This diagnostic is shown for code with inactive `#[cfg]` attributes.
+pub(super) fn inactive_code(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::InactiveCode,
+) -> Option<Diagnostic> {
+    // If there's inactive code somewhere in a macro, don't propagate to the call-site.
+    if d.node.file_id.expansion_info(ctx.sema.db).is_some() {
+        return None;
+    }
+
+    let inactive = DnfExpr::new(d.cfg.clone()).why_inactive(&d.opts);
+    let mut message = "code is inactive due to #[cfg] directives".to_string();
+
+    if let Some(inactive) = inactive {
+        format_to!(message, ": {}", inactive);
+    }
+
+    let res = Diagnostic::new(
+        "inactive-code",
+        message,
+        ctx.sema.diagnostics_display_range(d.node.clone()).range,
+    )
+    .severity(Severity::WeakWarning)
+    .with_unused(true);
+    Some(res)
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostics::tests::check_diagnostics_with_inactive_code;
+
+    #[test]
+    fn cfg_diagnostics() {
+        check_diagnostics_with_inactive_code(
+            r#"
+fn f() {
+    // The three g̶e̶n̶d̶e̶r̶s̶ statements:
+
+    #[cfg(a)] fn f() {}  // Item statement
+  //^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+    #[cfg(a)] {}         // Expression statement
+  //^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+    #[cfg(a)] let x = 0; // let statement
+  //^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+
+    abc(#[cfg(a)] 0);
+      //^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+    let x = Struct {
+        #[cfg(a)] f: 0,
+      //^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+    };
+    match () {
+        () => (),
+        #[cfg(a)] () => (),
+      //^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+    }
+
+    #[cfg(a)] 0          // Trailing expression of block
+  //^^^^^^^^^^^ code is inactive due to #[cfg] directives: a is disabled
+}
+        "#,
+            true,
+        );
+    }
+
+    #[test]
+    fn inactive_item() {
+        // Additional tests in `cfg` crate. This only tests disabled cfgs.
+
+        check_diagnostics_with_inactive_code(
+            r#"
+    #[cfg(no)] pub fn f() {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no is disabled
+
+    #[cfg(no)] #[cfg(no2)] mod m;
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no and no2 are disabled
+
+    #[cfg(all(not(a), b))] enum E {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: b is disabled
+
+    #[cfg(feature = "std")] use std;
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: feature = "std" is disabled
+"#,
+            true,
+        );
+    }
+
+    /// Tests that `cfg` attributes behind `cfg_attr` is handled properly.
+    #[test]
+    fn inactive_via_cfg_attr() {
+        cov_mark::check!(cfg_attr_active);
+        check_diagnostics_with_inactive_code(
+            r#"
+    #[cfg_attr(not(never), cfg(no))] fn f() {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no is disabled
+
+    #[cfg_attr(not(never), cfg(not(no)))] fn f() {}
+
+    #[cfg_attr(never, cfg(no))] fn g() {}
+
+    #[cfg_attr(not(never), inline, cfg(no))] fn h() {}
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ code is inactive due to #[cfg] directives: no is disabled
+"#,
+            true,
+        );
+    }
+}
diff --git a/crates/ide/src/diagnostics/macro_error.rs b/crates/ide/src/diagnostics/macro_error.rs
new file mode 100644
index 000000000..8cc8cfb48
--- /dev/null
+++ b/crates/ide/src/diagnostics/macro_error.rs
@@ -0,0 +1,163 @@
+use crate::diagnostics::{Diagnostic, DiagnosticsContext};
+
+// Diagnostic: macro-error
+//
+// This diagnostic is shown for macro expansion errors.
+pub(super) fn macro_error(ctx: &DiagnosticsContext<'_>, d: &hir::MacroError) -> Diagnostic {
+    Diagnostic::new(
+        "macro-error",
+        d.message.clone(),
+        ctx.sema.diagnostics_display_range(d.node.clone()).range,
+    )
+    .experimental()
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostics::tests::{check_diagnostics, check_no_diagnostics};
+
+    #[test]
+    fn builtin_macro_fails_expansion() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+
+  include!("doesntexist");
+//^^^^^^^^^^^^^^^^^^^^^^^^ failed to load file `doesntexist`
+            "#,
+        );
+    }
+
+    #[test]
+    fn include_macro_should_allow_empty_content() {
+        check_diagnostics(
+            r#"
+//- /lib.rs
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+
+include!("foo/bar.rs");
+//- /foo/bar.rs
+// empty
+"#,
+        );
+    }
+
+    #[test]
+    fn good_out_dir_diagnostic() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! include { () => {} }
+#[rustc_builtin_macro]
+macro_rules! env { () => {} }
+#[rustc_builtin_macro]
+macro_rules! concat { () => {} }
+
+  include!(concat!(env!("OUT_DIR"), "/out.rs"));
+//^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
+"#,
+        );
+    }
+
+    #[test]
+    fn register_attr_and_tool() {
+        cov_mark::check!(register_attr);
+        cov_mark::check!(register_tool);
+        check_no_diagnostics(
+            r#"
+#![register_tool(tool)]
+#![register_attr(attr)]
+
+#[tool::path]
+#[attr]
+struct S;
+"#,
+        );
+        // NB: we don't currently emit diagnostics here
+    }
+
+    #[test]
+    fn macro_diag_builtin() {
+        check_diagnostics(
+            r#"
+#[rustc_builtin_macro]
+macro_rules! env {}
+
+#[rustc_builtin_macro]
+macro_rules! include {}
+
+#[rustc_builtin_macro]
+macro_rules! compile_error {}
+
+#[rustc_builtin_macro]
+macro_rules! format_args { () => {} }
+
+fn main() {
+    // Test a handful of built-in (eager) macros:
+
+    include!(invalid);
+  //^^^^^^^^^^^^^^^^^ could not convert tokens
+    include!("does not exist");
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^ failed to load file `does not exist`
+
+    env!(invalid);
+  //^^^^^^^^^^^^^ could not convert tokens
+
+    env!("OUT_DIR");
+  //^^^^^^^^^^^^^^^ `OUT_DIR` not set, enable "run build scripts" to fix
+
+    compile_error!("compile_error works");
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ compile_error works
+
+    // Lazy:
+
+    format_args!();
+  //^^^^^^^^^^^^^^ no rule matches input tokens
+}
+"#,
+        );
+    }
+
+    #[test]
+    fn macro_rules_diag() {
+        check_diagnostics(
+            r#"
+macro_rules! m {
+    () => {};
+}
+fn f() {
+    m!();
+
+    m!(hi);
+  //^^^^^^ leftover tokens
+}
+      "#,
+        );
+    }
+    #[test]
+    fn dollar_crate_in_builtin_macro() {
+        check_diagnostics(
+            r#"
+#[macro_export]
+#[rustc_builtin_macro]
+macro_rules! format_args {}
+
+#[macro_export]
+macro_rules! arg { () => {} }
+
+#[macro_export]
+macro_rules! outer {
+    () => {
+        $crate::format_args!( "", $crate::arg!(1) )
+    };
+}
+
+fn f() {
+    outer!();
+} //^^^^^^^^ leftover tokens
+"#,
+        )
+    }
+}
diff --git a/crates/ide/src/diagnostics/unresolved_macro_call.rs b/crates/ide/src/diagnostics/unresolved_macro_call.rs
index a3af332a4..15b6a2730 100644
--- a/crates/ide/src/diagnostics/unresolved_macro_call.rs
+++ b/crates/ide/src/diagnostics/unresolved_macro_call.rs
@@ -35,6 +35,18 @@ mod tests {
     use crate::diagnostics::tests::check_diagnostics;
 
     #[test]
+    fn unresolved_macro_diag() {
+        check_diagnostics(
+            r#"
+fn f() {
+    m!();
+} //^ unresolved macro `m!`
+
+"#,
+        );
+    }
+
+    #[test]
     fn test_unresolved_macro_range() {
         check_diagnostics(
             r#"
diff --git a/crates/ide/src/diagnostics/unresolved_proc_macro.rs b/crates/ide/src/diagnostics/unresolved_proc_macro.rs
new file mode 100644
index 000000000..3dc6ab451
--- /dev/null
+++ b/crates/ide/src/diagnostics/unresolved_proc_macro.rs
@@ -0,0 +1,30 @@
+use crate::{
+    diagnostics::{Diagnostic, DiagnosticsContext},
+    Severity,
+};
+
+// Diagnostic: unresolved-proc-macro
+//
+// This diagnostic is shown when a procedural macro can not be found. This usually means that
+// procedural macro support is simply disabled (and hence is only a weak hint instead of an error),
+// but can also indicate project setup problems.
+//
+// If you are seeing a lot of "proc macro not expanded" warnings, you can add this option to the
+// `rust-analyzer.diagnostics.disabled` list to prevent them from showing. Alternatively you can
+// enable support for procedural macros (see `rust-analyzer.procMacro.enable`).
+pub(super) fn unresolved_proc_macro(
+    ctx: &DiagnosticsContext<'_>,
+    d: &hir::UnresolvedProcMacro,
+) -> Diagnostic {
+    // Use more accurate position if available.
+    let display_range = d
+        .precise_location
+        .unwrap_or_else(|| ctx.sema.diagnostics_display_range(d.node.clone()).range);
+    // FIXME: it would be nice to tell the user whether proc macros are currently disabled
+    let message = match &d.macro_name {
+        Some(name) => format!("proc macro `{}` not expanded", name),
+        None => "proc macro not expanded".to_string(),
+    };
+
+    Diagnostic::new("unresolved-proc-macro", message, display_range).severity(Severity::WeakWarning)
+}