Expose coercions for patterns and expressions in semantics

Author: Veykril

crates/hir/src/semantics.rs

@@ -216,14 +216,18 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         self.imp.type_of_expr(expr)
     }
 
-    pub fn type_of_expr_with_coercion(&self, expr: &ast::Expr) -> Option<Type> {
+    pub fn type_of_expr_with_coercion(&self, expr: &ast::Expr) -> Option<(Type, Option<Type>)> {
         self.imp.type_of_expr_with_coercion(expr)
     }
 
     pub fn type_of_pat(&self, pat: &ast::Pat) -> Option<Type> {
         self.imp.type_of_pat(pat)
     }
 
+    pub fn type_of_pat_with_coercion(&self, expr: &ast::Pat) -> Option<(Type, Option<Type>)> {
+        self.imp.type_of_pat_with_coercion(expr)
+    }
+
     pub fn type_of_self(&self, param: &ast::SelfParam) -> Option<Type> {
         self.imp.type_of_self(param)
     }
@@ -564,14 +568,18 @@ impl<'db> SemanticsImpl<'db> {
         self.analyze(expr.syntax()).type_of_expr(self.db, expr)
     }
 
-    fn type_of_expr_with_coercion(&self, expr: &ast::Expr) -> Option<Type> {
+    fn type_of_expr_with_coercion(&self, expr: &ast::Expr) -> Option<(Type, Option<Type>)> {
         self.analyze(expr.syntax()).type_of_expr_with_coercion(self.db, expr)
     }
 
     fn type_of_pat(&self, pat: &ast::Pat) -> Option<Type> {
         self.analyze(pat.syntax()).type_of_pat(self.db, pat)
     }
 
+    fn type_of_pat_with_coercion(&self, pat: &ast::Pat)-> Option<(Type, Option<Type>)> {
+        self.analyze(pat.syntax()).type_of_pat_with_coercion(self.db, pat)
+    }
+
     fn type_of_self(&self, param: &ast::SelfParam) -> Option<Type> {
         self.analyze(param.syntax()).type_of_self(self.db, param)
     }

crates/hir/src/source_analyzer.rs

@@ -126,15 +126,15 @@ impl SourceAnalyzer {
         &self,
         db: &dyn HirDatabase,
         expr: &ast::Expr,
-    ) -> Option<Type> {
+    ) -> Option<(Type, Option<Type>)> {
         let expr_id = self.expr_id(db, expr)?;
         let infer = self.infer.as_ref()?;
         let ty = infer
             .expr_adjustments
             .get(&expr_id)
-            .and_then(|adjusts| adjusts.last().map(|adjust| &adjust.target))
-            .unwrap_or_else(|| &infer[expr_id]);
-        Type::new_with_resolver(db, &self.resolver, ty.clone())
+            .and_then(|adjusts| adjusts.last().map(|adjust| &adjust.target));
+        let mk_ty = |ty: &hir_ty::Ty| Type::new_with_resolver(db, &self.resolver, ty.clone());
+        mk_ty(&infer[expr_id]).map(|it| (it, ty.and_then(mk_ty)))
     }
 
     pub(crate) fn type_of_pat(&self, db: &dyn HirDatabase, pat: &ast::Pat) -> Option<Type> {
@@ -143,6 +143,21 @@ impl SourceAnalyzer {
         Type::new_with_resolver(db, &self.resolver, ty)
     }
 
+    pub(crate) fn type_of_pat_with_coercion(
+        &self,
+        db: &dyn HirDatabase,
+        pat: &ast::Pat,
+    ) -> Option<(Type, Option<Type>)> {
+        let pat_id = self.pat_id(pat)?;
+        let infer = self.infer.as_ref()?;
+        let ty = infer
+            .pat_adjustments
+            .get(&pat_id)
+            .and_then(|adjusts| adjusts.last().map(|adjust| &adjust.target));
+        let mk_ty = |ty: &hir_ty::Ty| Type::new_with_resolver(db, &self.resolver, ty.clone());
+        mk_ty(&infer[pat_id]).map(|it| (it, ty.and_then(mk_ty)))
+    }
+
     pub(crate) fn type_of_self(
         &self,
         db: &dyn HirDatabase,

crates/ide_assists/src/handlers/add_explicit_type.rs

@@ -55,7 +55,8 @@ pub(crate) fn add_explicit_type(acc: &mut Assists, ctx: &AssistContext) -> Optio
     }
 
     // Infer type
-    let ty = ctx.sema.type_of_expr_with_coercion(&expr)?;
+    let (ty, coerced) = ctx.sema.type_of_expr_with_coercion(&expr)?;
+    let ty = coerced.unwrap_or(ty);
     if ty.contains_unknown() || ty.is_closure() {
         cov_mark::hit!(add_explicit_type_not_applicable_if_ty_not_inferred);
         return None;