3 files changed, 114 insertions, 15 deletions

diff --git a/crates/ra_ssr/src/matching.rs b/crates/ra_ssr/src/matching.rs
index 125bf3895..6e0b92352 100644
--- a/crates/ra_ssr/src/matching.rs
+++ b/crates/ra_ssr/src/matching.rs
@@ -3,7 +3,7 @@
 
 use crate::{
     parsing::{Constraint, NodeKind, Placeholder},
-    resolving::{ResolvedPattern, ResolvedRule},
+    resolving::{ResolvedPattern, ResolvedRule, UfcsCallInfo},
     SsrMatches,
 };
 use hir::Semantics;
@@ -190,11 +190,12 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
             return Ok(());
         }
         // We allow a UFCS call to match a method call, provided they resolve to the same function.
-        if let Some(pattern_function) = self.rule.pattern.ufcs_function_calls.get(pattern) {
-            if let (Some(pattern), Some(code)) =
-                (ast::CallExpr::cast(pattern.clone()), ast::MethodCallExpr::cast(code.clone()))
-            {
-                return self.attempt_match_ufcs(phase, &pattern, &code, *pattern_function);
+        if let Some(pattern_ufcs) = self.rule.pattern.ufcs_function_calls.get(pattern) {
+            if let Some(code) = ast::MethodCallExpr::cast(code.clone()) {
+                return self.attempt_match_ufcs_to_method_call(phase, pattern_ufcs, &code);
+            }
+            if let Some(code) = ast::CallExpr::cast(code.clone()) {
+                return self.attempt_match_ufcs_to_ufcs(phase, pattern_ufcs, &code);
             }
         }
         if pattern.kind() != code.kind() {
@@ -521,23 +522,28 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
         Ok(())
     }
 
-    fn attempt_match_ufcs(
+    fn attempt_match_ufcs_to_method_call(
         &self,
         phase: &mut Phase,
-        pattern: &ast::CallExpr,
+        pattern_ufcs: &UfcsCallInfo,
         code: &ast::MethodCallExpr,
-        pattern_function: hir::Function,
     ) -> Result<(), MatchFailed> {
         use ast::ArgListOwner;
         let code_resolved_function = self
             .sema
             .resolve_method_call(code)
             .ok_or_else(|| match_error!("Failed to resolve method call"))?;
-        if pattern_function != code_resolved_function {
+        if pattern_ufcs.function != code_resolved_function {
             fail_match!("Method call resolved to a different function");
         }
+        if code_resolved_function.has_self_param(self.sema.db) {
+            if let (Some(pattern_type), Some(expr)) = (&pattern_ufcs.qualifier_type, &code.expr()) {
+                self.check_expr_type(pattern_type, expr)?;
+            }
+        }
         // Check arguments.
-        let mut pattern_args = pattern
+        let mut pattern_args = pattern_ufcs
+            .call_expr
             .arg_list()
             .ok_or_else(|| match_error!("Pattern function call has no args"))?
             .args();
@@ -552,6 +558,45 @@ impl<'db, 'sema> Matcher<'db, 'sema> {
         }
     }
 
+    fn attempt_match_ufcs_to_ufcs(
+        &self,
+        phase: &mut Phase,
+        pattern_ufcs: &UfcsCallInfo,
+        code: &ast::CallExpr,
+    ) -> Result<(), MatchFailed> {
+        use ast::ArgListOwner;
+        // Check that the first argument is the expected type.
+        if let (Some(pattern_type), Some(expr)) = (
+            &pattern_ufcs.qualifier_type,
+            &code.arg_list().and_then(|code_args| code_args.args().next()),
+        ) {
+            self.check_expr_type(pattern_type, expr)?;
+        }
+        self.attempt_match_node_children(phase, pattern_ufcs.call_expr.syntax(), code.syntax())
+    }
+
+    fn check_expr_type(
+        &self,
+        pattern_type: &hir::Type,
+        expr: &ast::Expr,
+    ) -> Result<(), MatchFailed> {
+        use hir::HirDisplay;
+        let code_type = self.sema.type_of_expr(&expr).ok_or_else(|| {
+            match_error!("Failed to get receiver type for `{}`", expr.syntax().text())
+        })?;
+        if !code_type
+            .autoderef(self.sema.db)
+            .any(|deref_code_type| *pattern_type == deref_code_type)
+        {
+            fail_match!(
+                "Pattern type `{}` didn't match code type `{}`",
+                pattern_type.display(self.sema.db),
+                code_type.display(self.sema.db)
+            );
+        }
+        Ok(())
+    }
+
     fn get_placeholder(&self, element: &SyntaxElement) -> Option<&Placeholder> {
         only_ident(element.clone()).and_then(|ident| self.rule.get_placeholder(&ident))
     }
diff --git a/crates/ra_ssr/src/resolving.rs b/crates/ra_ssr/src/resolving.rs
index 7e7585c8b..bfc20705b 100644
--- a/crates/ra_ssr/src/resolving.rs
+++ b/crates/ra_ssr/src/resolving.rs
@@ -25,7 +25,7 @@ pub(crate) struct ResolvedPattern {
     pub(crate) node: SyntaxNode,
     // Paths in `node` that we've resolved.
     pub(crate) resolved_paths: FxHashMap<SyntaxNode, ResolvedPath>,
-    pub(crate) ufcs_function_calls: FxHashMap<SyntaxNode, hir::Function>,
+    pub(crate) ufcs_function_calls: FxHashMap<SyntaxNode, UfcsCallInfo>,
     pub(crate) contains_self: bool,
 }
 
@@ -35,6 +35,12 @@ pub(crate) struct ResolvedPath {
     pub(crate) depth: u32,
 }
 
+pub(crate) struct UfcsCallInfo {
+    pub(crate) call_expr: ast::CallExpr,
+    pub(crate) function: hir::Function,
+    pub(crate) qualifier_type: Option<hir::Type>,
+}
+
 impl ResolvedRule {
     pub(crate) fn new(
         rule: parsing::ParsedRule,
@@ -70,6 +76,7 @@ struct Resolver<'a, 'db> {
 
 impl Resolver<'_, '_> {
     fn resolve_pattern_tree(&self, pattern: SyntaxNode) -> Result<ResolvedPattern, SsrError> {
+        use syntax::ast::AstNode;
         use syntax::{SyntaxElement, T};
         let mut resolved_paths = FxHashMap::default();
         self.resolve(pattern.clone(), 0, &mut resolved_paths)?;
@@ -77,11 +84,15 @@ impl Resolver<'_, '_> {
             .iter()
             .filter_map(|(path_node, resolved)| {
                 if let Some(grandparent) = path_node.parent().and_then(|parent| parent.parent()) {
-                    if grandparent.kind() == SyntaxKind::CALL_EXPR {
+                    if let Some(call_expr) = ast::CallExpr::cast(grandparent.clone()) {
                         if let hir::PathResolution::AssocItem(hir::AssocItem::Function(function)) =
-                            &resolved.resolution
+                            resolved.resolution
                         {
-                            return Some((grandparent, *function));
+                            let qualifier_type = self.resolution_scope.qualifier_type(path_node);
+                            return Some((
+                                grandparent,
+                                UfcsCallInfo { call_expr, function, qualifier_type },
+                            ));
                         }
                     }
                 }
@@ -226,6 +237,20 @@ impl<'db> ResolutionScope<'db> {
             None
         }
     }
+
+    fn qualifier_type(&self, path: &SyntaxNode) -> Option<hir::Type> {
+        use syntax::ast::AstNode;
+        if let Some(path) = ast::Path::cast(path.clone()) {
+            if let Some(qualifier) = path.qualifier() {
+                if let Some(resolved_qualifier) = self.resolve_path(&qualifier) {
+                    if let hir::PathResolution::Def(hir::ModuleDef::Adt(adt)) = resolved_qualifier {
+                        return Some(adt.ty(self.scope.db));
+                    }
+                }
+            }
+        }
+        None
+    }
 }
 
 fn is_self(path: &ast::Path) -> bool {
diff --git a/crates/ra_ssr/src/tests.rs b/crates/ra_ssr/src/tests.rs
index 7d4d470c0..4bc09c1e4 100644
--- a/crates/ra_ssr/src/tests.rs
+++ b/crates/ra_ssr/src/tests.rs
@@ -1143,3 +1143,32 @@ fn replace_self() {
         "#]],
     );
 }
+
+#[test]
+fn match_trait_method_call() {
+    // `Bar::foo` and `Bar2::foo` resolve to the same function. Make sure we only match if the type
+    // matches what's in the pattern. Also checks that we handle autoderef.
+    let code = r#"
+        pub struct Bar {}
+        pub struct Bar2 {}
+        pub trait Foo {
+            fn foo(&self, _: i32) {}
+        }
+        impl Foo for Bar {}
+        impl Foo for Bar2 {}
+        fn main() {
+            let v1 = Bar {};
+            let v2 = Bar2 {};
+            let v1_ref = &v1;
+            let v2_ref = &v2;
+            v1.foo(1);
+            v2.foo(2);
+            Bar::foo(&v1, 3);
+            Bar2::foo(&v2, 4);
+            v1_ref.foo(5);
+            v2_ref.foo(6);
+        }
+        "#;
+    assert_matches("Bar::foo($a, $b)", code, &["v1.foo(1)", "Bar::foo(&v1, 3)", "v1_ref.foo(5)"]);
+    assert_matches("Bar2::foo($a, $b)", code, &["v2.foo(2)", "Bar2::foo(&v2, 4)", "v2_ref.foo(6)"]);
+}