Merge #5007

5007: SSR: Allow matching within macro calls r=matklad a=davidlattimore

#3186 

Co-authored-by: David Lattimore <dml@google.com>

crates/ra_ssr/src/lib.rs

@@ -12,7 +12,7 @@ mod tests;
 use crate::matching::Match;
 use hir::Semantics;
 use ra_db::{FileId, FileRange};
-use ra_syntax::{AstNode, SmolStr, SyntaxNode};
+use ra_syntax::{ast, AstNode, SmolStr, SyntaxNode};
 use ra_text_edit::TextEdit;
 use rustc_hash::FxHashMap;
 
@@ -107,6 +107,22 @@ impl<'db> MatchFinder<'db> {
                 return;
             }
         }
+        // If we've got a macro call, we already tried matching it pre-expansion, which is the only
+        // way to match the whole macro, now try expanding it and matching the expansion.
+        if let Some(macro_call) = ast::MacroCall::cast(code.clone()) {
+            if let Some(expanded) = self.sema.expand(&macro_call) {
+                if let Some(tt) = macro_call.token_tree() {
+                    // When matching within a macro expansion, we only want to allow matches of
+                    // nodes that originated entirely from within the token tree of the macro call.
+                    // i.e. we don't want to match something that came from the macro itself.
+                    self.find_matches(
+                        &expanded,
+                        &Some(self.sema.original_range(tt.syntax())),
+                        matches_out,
+                    );
+                }
+            }
+        }
         for child in code.children() {
             self.find_matches(&child, restrict_range, matches_out);
         }

crates/ra_ssr/src/matching.rs

@@ -343,7 +343,9 @@ impl<'db, 'sema> MatchState<'db, 'sema> {
     }
 
     /// Outside of token trees, a placeholder can only match a single AST node, whereas in a token
-    /// tree it can match a sequence of tokens.
+    /// tree it can match a sequence of tokens. Note, that this code will only be used when the
+    /// pattern matches the macro invocation. For matches within the macro call, we'll already have
+    /// expanded the macro.
     fn attempt_match_token_tree(
         &mut self,
         match_inputs: &MatchInputs,

crates/ra_ssr/src/tests.rs

@@ -209,6 +209,11 @@ fn assert_ssr_transform(rule: &str, input: &str, result: &str) {
     assert_ssr_transforms(&[rule], input, result);
 }
 
+fn normalize_code(code: &str) -> String {
+    let (db, file_id) = single_file(code);
+    db.file_text(file_id).to_string()
+}
+
 fn assert_ssr_transforms(rules: &[&str], input: &str, result: &str) {
     let (db, file_id) = single_file(input);
     let mut match_finder = MatchFinder::new(&db);
@@ -217,8 +222,13 @@ fn assert_ssr_transforms(rules: &[&str], input: &str, result: &str) {
         match_finder.add_rule(rule);
     }
     if let Some(edits) = match_finder.edits_for_file(file_id) {
-        let mut after = input.to_string();
+        // Note, db.file_text is not necessarily the same as `input`, since fixture parsing alters
+        // stuff.
+        let mut after = db.file_text(file_id).to_string();
         edits.apply(&mut after);
+        // Likewise, we need to make sure that whatever transformations fixture parsing applies,
+        // also get appplied to our expected result.
+        let result = normalize_code(result);
         assert_eq!(after, result);
     } else {
         panic!("No edits were made");
@@ -355,6 +365,18 @@ fn match_nested_method_calls() {
     );
 }
 
+// Make sure that our node matching semantics don't differ within macro calls.
+#[test]
+fn match_nested_method_calls_with_macro_call() {
+    assert_matches(
+        "$a.z().z().z()",
+        r#"
+            macro_rules! m1 { ($a:expr) => {$a}; }
+            fn f() {m1!(h().i().j().z().z().z().d().e())}"#,
+        &["h().i().j().z().z().z()"],
+    );
+}
+
 #[test]
 fn match_complex_expr() {
     let code = "fn f() -> i32 {foo(bar(40, 2), 42)}";
@@ -547,3 +569,40 @@ fn multiple_rules() {
         "fn f() -> i32 {add_one(add(3, 2))}",
     )
 }
+
+#[test]
+fn match_within_macro_invocation() {
+    let code = r#"
+            macro_rules! foo {
+                ($a:stmt; $b:expr) => {
+                    $b
+                };
+            }
+            struct A {}
+            impl A {
+                fn bar() {}
+            }
+            fn f1() {
+                let aaa = A {};
+                foo!(macro_ignores_this(); aaa.bar());
+            }
+        "#;
+    assert_matches("$a.bar()", code, &["aaa.bar()"]);
+}
+
+#[test]
+fn replace_within_macro_expansion() {
+    assert_ssr_transform(
+        "$a.foo() ==>> bar($a)",
+        r#"
+            macro_rules! macro1 {
+                ($a:expr) => {$a}
+            }
+            fn f() {macro1!(5.x().foo().o2())}"#,
+        r#"
+            macro_rules! macro1 {
+                ($a:expr) => {$a}
+            }
+            fn f() {macro1!(bar(5.x()).o2())}"#,
+    )
+}