Merge pull request #81675 from DougGregor/unsafe-pattern-match

[Strict memory safety] Lift "unsafe" in pattern match expressions

Author: DougGregor

lib/Sema/TypeCheckPattern.cpp

@@ -768,13 +768,27 @@ ExprPatternMatchRequest::evaluate(Evaluator &evaluator,
       DeclNameLoc(EP->getLoc()));
   matchOp->setImplicit();
 
+  auto subExpr = EP->getSubExpr();
+
+  // Pull off the outer "unsafe" expression.
+  UnsafeExpr *unsafeExpr = dyn_cast<UnsafeExpr>(subExpr);
+  if (unsafeExpr) {
+    subExpr = unsafeExpr->getSubExpr();
+  }
+
   // Note we use getEndLoc here to have the BinaryExpr source range be the same
   // as the expr pattern source range.
   auto *matchVarRef =
       new (ctx) DeclRefExpr(matchVar, DeclNameLoc(EP->getEndLoc()),
                             /*Implicit=*/true);
-  auto *matchCall = BinaryExpr::create(ctx, EP->getSubExpr(), matchOp,
+  Expr *matchCall = BinaryExpr::create(ctx, subExpr, matchOp,
                                        matchVarRef, /*implicit*/ true);
+
+  // If there was an "unsafe", put it outside of the match call.
+  if (unsafeExpr) {
+    matchCall = UnsafeExpr::createImplicit(ctx, unsafeExpr->getLoc(), matchCall);
+  }
+
   return {matchVar, matchCall};
 }
 

lib/Sema/TypeCheckUnsafe.cpp

@@ -165,20 +165,20 @@ void swift::diagnoseUnsafeUse(const UnsafeUse &use) {
         ctx.Diags.diagnose(
             loc,
             diag::note_unsafe_call_decl_argument_indexed,
-            calleeDecl, argumentIndex, paramType)
+            calleeDecl, argumentIndex, argument->getType())
           .highlight(argument->getSourceRange());
       } else {
         ctx.Diags.diagnose(
             loc,
             diag::note_unsafe_call_decl_argument_named,
-            calleeDecl, argumentName, paramType)
+            calleeDecl, argumentName, argument->getType())
           .highlight(argument->getSourceRange());
       }
     } else {
       ctx.Diags.diagnose(
           loc,
           diag::note_unsafe_call_argument_indexed,
-          argumentIndex, paramType)
+          argumentIndex, argument->getType())
         .highlight(argument->getSourceRange());
     }
 

test/Unsafe/safe.swift

@@ -317,3 +317,35 @@ extension Slice {
     }
   }
 }
+
+@unsafe enum SomeEnum {
+  case first
+  case second
+}
+
+@unsafe var someEnumValue: SomeEnum = unsafe .first
+
+func testSwitch(se: SomeEnum) {
+  switch unsafe se {
+  case unsafe someEnumValue: break
+  default: break
+  }
+
+  switch unsafe se {
+  case someEnumValue: break
+    // expected-warning@-1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{8-8=unsafe }}
+    // expected-note@-2{{argument #0 in call to operator function '~=' has unsafe type 'SomeEnum'}}
+    // expected-note@-3{{argument #1 in call to operator function '~=' has unsafe type 'SomeEnum'}}
+    // expected-note@-4{{reference to unsafe type 'SomeEnum'}}
+    // expected-note@-5{{reference to unsafe var 'someEnumValue'}}
+    // expected-note@-6{{reference to let '$match' involves unsafe type 'SomeEnum'}}
+  default: break
+  }
+
+  // expected-note@+2{{reference to parameter 'se' involves unsafe type 'SomeEnum'}}
+  // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{10-10=unsafe }}
+  switch se {
+  case unsafe someEnumValue: break
+  default: break
+  }
+}

test/Unsafe/unsafe.swift

@@ -49,7 +49,7 @@ extension ConformsToMultiP: MultiP {
   // expected-note@-1{{unsafe type 'UnsafeSuper' cannot satisfy safe associated type 'Ptr'}}
   @unsafe func f() -> UnsafeSuper {
     .init() // expected-warning{{expression uses unsafe constructs but is not marked with 'unsafe'}}
-    // expected-note@-1{{argument 'self' in call to initializer 'init' has unsafe type 'UnsafeSuper'}}
+    // expected-note@-1{{argument 'self' in call to initializer 'init' has unsafe type 'UnsafeSuper.Type'}}
   }
 }
 

test/Unsafe/unsafe_stdlib.swift

@@ -9,7 +9,7 @@ func test(
 ) {
   var array = [1, 2, 3]
   // expected-warning@+2{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{3-3=unsafe }}
-  // expected-note@+1{{argument #0 in call to instance method 'withUnsafeBufferPointer' has unsafe type '(UnsafeBufferPointer<Element>) throws(E) -> R'}}
+  // expected-note@+1{{argument #0 in call to instance method 'withUnsafeBufferPointer' has unsafe type '(UnsafeBufferPointer<Int>) -> ()'}}
   array.withUnsafeBufferPointer{ buffer in
   // expected-warning@+1{{expression uses unsafe constructs but is not marked with 'unsafe'}}{{5-5=unsafe }}
     print(buffer) // expected-note{{reference to parameter 'buffer' involves unsafe type 'UnsafeBufferPointer<Int>'}}