Merge pull request swiftlang#34294 from CodaFi/patterns-as-compiler-bugs

Author: swift-ci

lib/Sema/DerivedConformanceCodable.cpp

@@ -799,8 +799,10 @@ deriveBodyDecodable_init(AbstractFunctionDecl *initDecl, void *) {
               diag::decodable_property_init_or_codingkeys_explicit,
               varDecl->getName());
         }
-        varDecl->diagnose(diag::decodable_make_property_mutable)
-            .fixItReplace(varDecl->getAttributeInsertionLoc(true), "var");
+        if (auto *PBD = varDecl->getParentPatternBinding()) {
+          varDecl->diagnose(diag::decodable_make_property_mutable)
+              .fixItReplace(PBD->getLoc(), "var");
+        }
 
         continue;
       }

test/decl/protocol/special/coding/immutable_property.swift

@@ -0,0 +1,28 @@
+// RUN: %target-typecheck-verify-swift -verify-ignore-unknown
+
+struct Foo : Codable {
+  let x1: String = ""
+  // expected-warning@-1 {{immutable property will not be decoded because it is declared with an initial value which cannot be overwritten}}
+  // expected-note@-2 {{set the initial value via the initializer or explicitly define a CodingKeys enum including a 'x1' case to silence this warning}}
+  // expected-note@-3 {{make the property mutable instead}}{{3-6=var}}
+
+  public let x2: String = ""
+  // expected-warning@-1 {{immutable property will not be decoded because it is declared with an initial value which cannot be overwritten}}
+  // expected-note@-2 {{set the initial value via the initializer or explicitly define a CodingKeys enum including a 'x2' case to silence this warning}}
+  // expected-note@-3 {{make the property mutable instead}}{{10-13=var}}
+
+  internal let x3: String = ""
+  // expected-warning@-1 {{immutable property will not be decoded because it is declared with an initial value which cannot be overwritten}}
+  // expected-note@-2 {{set the initial value via the initializer or explicitly define a CodingKeys enum including a 'x3' case to silence this warning}}
+  // expected-note@-3 {{make the property mutable instead}}{{12-15=var}}
+
+  fileprivate let x4: String = ""
+  // expected-warning@-1 {{immutable property will not be decoded because it is declared with an initial value which cannot be overwritten}}
+  // expected-note@-2 {{set the initial value via the initializer or explicitly define a CodingKeys enum including a 'x4' case to silence this warning}}
+  // expected-note@-3 {{make the property mutable instead}}{{15-18=var}}
+
+  private let x5: String = ""
+  // expected-warning@-1 {{immutable property will not be decoded because it is declared with an initial value which cannot be overwritten}}
+  // expected-note@-2 {{set the initial value via the initializer or explicitly define a CodingKeys enum including a 'x5' case to silence this warning}}
+  // expected-note@-3 {{make the property mutable instead}}{{11-14=var}}
+}