Merge #505

505: Inherent methods r=matklad a=flodiebold

This adds resolution, type checking and completion for inherent methods.

The main open question here is the caching, I think. I'm not sure whether we should be caching method resolutions in a more fine grained way (currently we just build a hash map of types -> impl blocks, and iterate through all potential impl blocks when looking for a method).

Co-authored-by: Florian Diebold <[email protected]>

3 files changed, 64 insertions, 5 deletions

diff --git a/crates/ra_ide_api/src/completion/complete_dot.rs b/crates/ra_ide_api/src/completion/complete_dot.rs
index 80d0b1663..37985b398 100644
--- a/crates/ra_ide_api/src/completion/complete_dot.rs
+++ b/crates/ra_ide_api/src/completion/complete_dot.rs
@@ -17,8 +17,9 @@ pub(super) fn complete_dot(acc: &mut Completions, ctx: &CompletionContext) -> Ca
     };
     let receiver_ty = infer_result[expr].clone();
     if !ctx.is_call {
-        complete_fields(acc, ctx, receiver_ty)?;
+        complete_fields(acc, ctx, receiver_ty.clone())?;
     }
+    complete_methods(acc, ctx, receiver_ty)?;
     Ok(())
 }
 
@@ -55,6 +56,24 @@ fn complete_fields(acc: &mut Completions, ctx: &CompletionContext, receiver: Ty)
     Ok(())
 }
 
+fn complete_methods(
+    acc: &mut Completions,
+    ctx: &CompletionContext,
+    receiver: Ty,
+) -> Cancelable<()> {
+    receiver.iterate_methods(ctx.db, |func| {
+        let sig = func.signature(ctx.db);
+        if sig.has_self_param() {
+            CompletionItem::new(CompletionKind::Reference, sig.name().to_string())
+                .from_function(ctx, func)
+                .kind(CompletionItemKind::Method)
+                .add_to(acc);
+        }
+        Ok(None::<()>)
+    })?;
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use crate::completion::*;
@@ -87,7 +106,8 @@ mod tests {
                 }
             }
             ",
-            r#"the_field "(u32,)""#,
+            r#"the_field "(u32,)"
+               foo "foo($0)""#,
         );
     }
 
@@ -102,7 +122,8 @@ mod tests {
                 }
             }
             ",
-            r#"the_field "(u32, i32)""#,
+            r#"the_field "(u32, i32)"
+               foo "foo($0)""#,
         );
     }
 
@@ -118,4 +139,36 @@ mod tests {
             r#""#,
         );
     }
+
+    #[test]
+    fn test_method_completion() {
+        check_ref_completion(
+            r"
+            struct A {}
+            impl A {
+                fn the_method(&self) {}
+            }
+            fn foo(a: A) {
+               a.<|>
+            }
+            ",
+            r#"the_method "the_method($0)""#,
+        );
+    }
+
+    #[test]
+    fn test_no_non_self_method() {
+        check_ref_completion(
+            r"
+            struct A {}
+            impl A {
+                fn the_method() {}
+            }
+            fn foo(a: A) {
+               a.<|>
+            }
+            ",
+            r#""#,
+        );
+    }
 }
diff --git a/crates/ra_ide_api/src/completion/completion_item.rs b/crates/ra_ide_api/src/completion/completion_item.rs
index e7fa967a0..b75d65de3 100644
--- a/crates/ra_ide_api/src/completion/completion_item.rs
+++ b/crates/ra_ide_api/src/completion/completion_item.rs
@@ -37,6 +37,7 @@ pub enum CompletionItemKind {
     Const,
     Trait,
     TypeAlias,
+    Method,
 }
 
 #[derive(Debug, PartialEq, Eq)]
@@ -183,10 +184,14 @@ impl Builder {
         self
     }
 
-    fn from_function(mut self, ctx: &CompletionContext, function: hir::Function) -> Builder {
+    pub(super) fn from_function(
+        mut self,
+        ctx: &CompletionContext,
+        function: hir::Function,
+    ) -> Builder {
         // If not an import, add parenthesis automatically.
         if ctx.use_item_syntax.is_none() && !ctx.is_call {
-            if function.signature(ctx.db).args().is_empty() {
+            if function.signature(ctx.db).params().is_empty() {
                 self.snippet = Some(format!("{}()$0", self.label));
             } else {
                 self.snippet = Some(format!("{}($0)", self.label));
diff --git a/crates/ra_ide_api/src/db.rs b/crates/ra_ide_api/src/db.rs
index efdf261be..60f84675d 100644
--- a/crates/ra_ide_api/src/db.rs
+++ b/crates/ra_ide_api/src/db.rs
@@ -124,6 +124,7 @@ salsa::database_storage! {
             fn enum_data() for hir::db::EnumDataQuery;
             fn enum_variant_data() for hir::db::EnumVariantDataQuery;
             fn impls_in_module() for hir::db::ImplsInModuleQuery;
+            fn impls_in_crate() for hir::db::ImplsInCrateQuery;
             fn body_hir() for hir::db::BodyHirQuery;
             fn body_syntax_mapping() for hir::db::BodySyntaxMappingQuery;
             fn fn_signature() for hir::db::FnSignatureQuery;