Merge #5197

5197: SSR internal refactorings r=davidlattimore a=davidlattimore

- Extract error code out to a separate module
- Improve error reporting when a test fails
- Refactor matching code
- Update tests so that all paths in search patterns can be resolved

Co-authored-by: David Lattimore <[email protected]>

Author: bors[bot]

crates/ra_ssr/src/errors.rs

@@ -0,0 +1,29 @@
+//! Code relating to errors produced by SSR.
+
+/// Constructs an SsrError taking arguments like the format macro.
+macro_rules! _error {
+    ($fmt:expr) => {$crate::SsrError::new(format!($fmt))};
+    ($fmt:expr, $($arg:tt)+) => {$crate::SsrError::new(format!($fmt, $($arg)+))}
+}
+pub(crate) use _error as error;
+
+/// Returns from the current function with an error, supplied by arguments as for format!
+macro_rules! _bail {
+    ($($tokens:tt)*) => {return Err(crate::errors::error!($($tokens)*))}
+}
+pub(crate) use _bail as bail;
+
+#[derive(Debug, PartialEq)]
+pub struct SsrError(pub(crate) String);
+
+impl std::fmt::Display for SsrError {
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "Parse error: {}", self.0)
+    }
+}
+
+impl SsrError {
+    pub(crate) fn new(message: impl Into<String>) -> SsrError {
+        SsrError(message.into())
+    }
+}

crates/ra_ssr/src/lib.rs

@@ -6,9 +6,12 @@
 mod matching;
 mod parsing;
 mod replacing;
+#[macro_use]
+mod errors;
 #[cfg(test)]
 mod tests;
 
+pub use crate::errors::SsrError;
 pub use crate::matching::Match;
 use crate::matching::{record_match_fails_reasons_scope, MatchFailureReason};
 use hir::Semantics;
@@ -41,9 +44,6 @@ pub struct SsrPattern {
     pattern: Option<SyntaxNode>,
 }
 
-#[derive(Debug, PartialEq)]
-pub struct SsrError(String);
-
 #[derive(Debug, Default)]
 pub struct SsrMatches {
     pub matches: Vec<Match>,
@@ -201,9 +201,8 @@ impl<'db> MatchFinder<'db> {
                         );
                     }
                 }
-            } else {
-                self.output_debug_for_nodes_at_range(&node, range, restrict_range, out);
             }
+            self.output_debug_for_nodes_at_range(&node, range, restrict_range, out);
         }
     }
 }
@@ -216,33 +215,28 @@ pub struct MatchDebugInfo {
     matched: Result<Match, MatchFailureReason>,
 }
 
-impl std::fmt::Display for SsrError {
-    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
-        write!(f, "Parse error: {}", self.0)
-    }
-}
-
 impl std::fmt::Debug for MatchDebugInfo {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        write!(f, "========= PATTERN ==========\n")?;
+        match &self.matched {
+            Ok(_) => writeln!(f, "Node matched")?,
+            Err(reason) => writeln!(f, "Node failed to match because: {}", reason.reason)?,
+        }
+        writeln!(
+            f,
+            "============ AST ===========\n\
+            {:#?}",
+            self.node
+        )?;
+        writeln!(f, "========= PATTERN ==========")?;
         match &self.pattern {
             Ok(pattern) => {
-                write!(f, "{:#?}", pattern)?;
+                writeln!(f, "{:#?}", pattern)?;
             }
             Err(err) => {
-                write!(f, "{}", err.reason)?;
+                writeln!(f, "{}", err.reason)?;
             }
         }
-        write!(
-            f,
-            "\n============ AST ===========\n\
-            {:#?}\n============================\n",
-            self.node
-        )?;
-        match &self.matched {
-            Ok(_) => write!(f, "Node matched")?,
-            Err(reason) => write!(f, "Node failed to match because: {}", reason.reason)?,
-        }
+        writeln!(f, "============================")?;
         Ok(())
     }
 }