Merge #1734

1734: Strip indents and empty lines in check_apply_diagnostic_fix_from_position r=matklad a=matklad



Co-authored-by: Phil Ellison <[email protected]>

4 files changed, 98 insertions, 4 deletions

diff --git a/crates/ra_hir/src/diagnostics.rs b/crates/ra_hir/src/diagnostics.rs
index 301109cb8..475dd5766 100644
--- a/crates/ra_hir/src/diagnostics.rs
+++ b/crates/ra_hir/src/diagnostics.rs
@@ -143,3 +143,31 @@ impl AstDiagnostic for MissingFields {
         ast::RecordFieldList::cast(node).unwrap()
     }
 }
+
+#[derive(Debug)]
+pub struct MissingOkInTailExpr {
+    pub file: HirFileId,
+    pub expr: AstPtr<ast::Expr>,
+}
+
+impl Diagnostic for MissingOkInTailExpr {
+    fn message(&self) -> String {
+        "wrap return expression in Ok".to_string()
+    }
+    fn source(&self) -> Source<SyntaxNodePtr> {
+        Source { file_id: self.file, ast: self.expr.into() }
+    }
+    fn as_any(&self) -> &(dyn Any + Send + 'static) {
+        self
+    }
+}
+
+impl AstDiagnostic for MissingOkInTailExpr {
+    type AST = ast::Expr;
+
+    fn ast(&self, db: &impl HirDatabase) -> Self::AST {
+        let root = db.parse_or_expand(self.file).unwrap();
+        let node = self.source().ast.to_node(&root);
+        ast::Expr::cast(node).unwrap()
+    }
+}
diff --git a/crates/ra_hir/src/expr/validation.rs b/crates/ra_hir/src/expr/validation.rs
index 62f7d41f5..5d9d59ff8 100644
--- a/crates/ra_hir/src/expr/validation.rs
+++ b/crates/ra_hir/src/expr/validation.rs
@@ -6,11 +6,14 @@ use ra_syntax::ast::{AstNode, RecordLit};
 use super::{Expr, ExprId, RecordLitField};
 use crate::{
     adt::AdtDef,
-    diagnostics::{DiagnosticSink, MissingFields},
+    diagnostics::{DiagnosticSink, MissingFields, MissingOkInTailExpr},
     expr::AstPtr,
-    ty::InferenceResult,
-    Function, HasSource, HirDatabase, Name, Path,
+    name,
+    path::{PathKind, PathSegment},
+    ty::{ApplicationTy, InferenceResult, Ty, TypeCtor},
+    Function, HasSource, HirDatabase, ModuleDef, Name, Path, PerNs, Resolution,
 };
+use ra_syntax::ast;
 
 pub(crate) struct ExprValidator<'a, 'b: 'a> {
     func: Function,
@@ -29,11 +32,17 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
 
     pub(crate) fn validate_body(&mut self, db: &impl HirDatabase) {
         let body = self.func.body(db);
+
         for e in body.exprs() {
             if let (id, Expr::RecordLit { path, fields, spread }) = e {
                 self.validate_record_literal(id, path, fields, *spread, db);
             }
         }
+
+        let body_expr = &body[body.body_expr()];
+        if let Expr::Block { statements: _, tail: Some(t) } = body_expr {
+            self.validate_results_in_tail_expr(*t, db);
+        }
     }
 
     fn validate_record_literal(
@@ -87,4 +96,42 @@ impl<'a, 'b> ExprValidator<'a, 'b> {
             })
         }
     }
+
+    fn validate_results_in_tail_expr(&mut self, id: ExprId, db: &impl HirDatabase) {
+        let mismatch = match self.infer.type_mismatch_for_expr(id) {
+            Some(m) => m,
+            None => return,
+        };
+
+        let std_result_path = Path {
+            kind: PathKind::Abs,
+            segments: vec![
+                PathSegment { name: name::STD, args_and_bindings: None },
+                PathSegment { name: name::RESULT_MOD, args_and_bindings: None },
+                PathSegment { name: name::RESULT_TYPE, args_and_bindings: None },
+            ],
+        };
+
+        let resolver = self.func.resolver(db);
+        let std_result_enum =
+            match resolver.resolve_path_segments(db, &std_result_path).into_fully_resolved() {
+                PerNs { types: Some(Resolution::Def(ModuleDef::Enum(e))), .. } => e,
+                _ => return,
+            };
+
+        let std_result_ctor = TypeCtor::Adt(AdtDef::Enum(std_result_enum));
+        let params = match &mismatch.expected {
+            Ty::Apply(ApplicationTy { ctor, parameters }) if ctor == &std_result_ctor => parameters,
+            _ => return,
+        };
+
+        if params.len() == 2 && &params[0] == &mismatch.actual {
+            let source_map = self.func.body_source_map(db);
+            let file_id = self.func.source(db).file_id;
+
+            if let Some(expr) = source_map.expr_syntax(id).and_then(|n| n.cast::<ast::Expr>()) {
+                self.sink.push(MissingOkInTailExpr { file: file_id, expr });
+            }
+        }
+    }
 }
diff --git a/crates/ra_hir/src/name.rs b/crates/ra_hir/src/name.rs
index 6d14eea8e..9c4822d91 100644
--- a/crates/ra_hir/src/name.rs
+++ b/crates/ra_hir/src/name.rs
@@ -120,6 +120,8 @@ pub(crate) const TRY: Name = Name::new(SmolStr::new_inline_from_ascii(3, b"Try")
 pub(crate) const OK: Name = Name::new(SmolStr::new_inline_from_ascii(2, b"Ok"));
 pub(crate) const FUTURE_MOD: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"future"));
 pub(crate) const FUTURE_TYPE: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"Future"));
+pub(crate) const RESULT_MOD: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"result"));
+pub(crate) const RESULT_TYPE: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"Result"));
 pub(crate) const OUTPUT: Name = Name::new(SmolStr::new_inline_from_ascii(6, b"Output"));
 
 fn resolve_name(text: &SmolStr) -> SmolStr {
diff --git a/crates/ra_hir/src/ty/infer.rs b/crates/ra_hir/src/ty/infer.rs
index b33de5687..d94e8154b 100644
--- a/crates/ra_hir/src/ty/infer.rs
+++ b/crates/ra_hir/src/ty/infer.rs
@@ -106,6 +106,13 @@ impl Default for BindingMode {
     }
 }
 
+/// A mismatch between an expected and an inferred type.
+#[derive(Clone, PartialEq, Eq, Debug, Hash)]
+pub struct TypeMismatch {
+    pub expected: Ty,
+    pub actual: Ty,
+}
+
 /// The result of type inference: A mapping from expressions and patterns to types.
 #[derive(Clone, PartialEq, Eq, Debug, Default)]
 pub struct InferenceResult {
@@ -120,6 +127,7 @@ pub struct InferenceResult {
     diagnostics: Vec<InferenceDiagnostic>,
     pub(super) type_of_expr: ArenaMap<ExprId, Ty>,
     pub(super) type_of_pat: ArenaMap<PatId, Ty>,
+    pub(super) type_mismatches: ArenaMap<ExprId, TypeMismatch>,
 }
 
 impl InferenceResult {
@@ -141,6 +149,9 @@ impl InferenceResult {
     pub fn assoc_resolutions_for_pat(&self, id: PatId) -> Option<ImplItem> {
         self.assoc_resolutions.get(&id.into()).copied()
     }
+    pub fn type_mismatch_for_expr(&self, expr: ExprId) -> Option<&TypeMismatch> {
+        self.type_mismatches.get(expr)
+    }
     pub(crate) fn add_diagnostics(
         &self,
         db: &impl HirDatabase,
@@ -1345,9 +1356,15 @@ impl<'a, D: HirDatabase> InferenceContext<'a, D> {
         };
         // use a new type variable if we got Ty::Unknown here
         let ty = self.insert_type_vars_shallow(ty);
-        self.unify(&ty, &expected.ty);
+        let could_unify = self.unify(&ty, &expected.ty);
         let ty = self.resolve_ty_as_possible(&mut vec![], ty);
         self.write_expr_ty(tgt_expr, ty.clone());
+        if !could_unify {
+            self.result.type_mismatches.insert(
+                tgt_expr,
+                TypeMismatch { expected: expected.ty.clone(), actual: ty.clone() },
+            );
+        }
         ty
     }