Fix the condition for warning about implicit capture of self captures.

lib/Sema/MiscDiagnostics.cpp

@@ -1615,6 +1615,15 @@ static void diagnoseImplicitSelfUseInClosure(const Expr *E,
       // Diagnostics should correct the innermost closure
       auto *ACE = Closures[Closures.size() - 1];
       assert(ACE);
+
+      // Until Swift 6, only emit a warning when we get this with an
+      // explicit capture, since we used to not diagnose this at all.
+      auto shouldOnlyWarn = [&](Expr *selfRef) {
+        // We know that isImplicitSelfParamUseLikelyToCauseCycle is true,
+        // which means all these casts are valid.
+        return !cast<VarDecl>(cast<DeclRefExpr>(selfRef)->getDecl())
+                  ->isSelfParameter();
+      };
 
       SourceLoc memberLoc = SourceLoc();
       if (auto *MRE = dyn_cast<MemberRefExpr>(E))
@@ -1624,7 +1633,7 @@ static void diagnoseImplicitSelfUseInClosure(const Expr *E,
           Diags.diagnose(memberLoc,
                          diag::property_use_in_closure_without_explicit_self,
                          baseName.getIdentifier())
-               .warnUntilSwiftVersionIf(Closures.size() > 1, 6);
+               .warnUntilSwiftVersionIf(shouldOnlyWarn(MRE->getBase()), 6);
         }
 
       // Handle method calls with a specific diagnostic + fixit.
@@ -1636,7 +1645,7 @@ static void diagnoseImplicitSelfUseInClosure(const Expr *E,
           Diags.diagnose(DSCE->getLoc(),
                          diag::method_call_in_closure_without_explicit_self,
                          MethodExpr->getDecl()->getBaseIdentifier())
-               .warnUntilSwiftVersionIf(Closures.size() > 1, 6);
+               .warnUntilSwiftVersionIf(shouldOnlyWarn(DSCE->getBase()), 6);
         }
 
       if (memberLoc.isValid()) {
@@ -1647,7 +1656,7 @@ static void diagnoseImplicitSelfUseInClosure(const Expr *E,
       // Catch any other implicit uses of self with a generic diagnostic.
       if (isImplicitSelfParamUseLikelyToCauseCycle(E, ACE))
         Diags.diagnose(E->getLoc(), diag::implicit_use_of_self_in_closure)
-             .warnUntilSwiftVersionIf(Closures.size() > 1, 6);
+             .warnUntilSwiftVersionIf(shouldOnlyWarn(E), 6);
 
       return { true, E };
     }

test/attr/attr_noescape.swift

@@ -91,25 +91,25 @@ class SomeClass {
 
     let _: () -> Void = {  // expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{26-26= [self] in}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{26-26= [self] in}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{26-26= [self] in}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{26-26= [self] in}}
       func inner() { foo() } // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{22-22=self.}}
-      let inner2 = { foo() } // expected-warning {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{21-21= [self] in}} expected-note{{reference 'self.' explicitly}} {{22-22=self.}}
+      let inner2 = { foo() } // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{21-21= [self] in}} expected-note{{reference 'self.' explicitly}} {{22-22=self.}}
       let _ = inner2
       func multi() -> Int { foo(); return 0 } // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{29-29=self.}}
       let multi2: () -> Int = { foo(); return 0 } // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{32-32= [self] in}} expected-note{{reference 'self.' explicitly}} {{33-33=self.}}
       let _ = multi2
-      doesEscape { foo() }  // expected-warning {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{19-19= [self] in}} expected-note{{reference 'self.' explicitly}} {{20-20=self.}}
+      doesEscape { foo() }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{19-19= [self] in}} expected-note{{reference 'self.' explicitly}} {{20-20=self.}}
       takesNoEscapeClosure { foo() }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{30-30=self.}}
       doesEscape { foo(); return 0 }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{19-19= [self] in}} expected-note{{reference 'self.' explicitly}} {{20-20=self.}}
       takesNoEscapeClosure { foo(); return 0 }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{30-30=self.}}
     }
 
     doesEscape {  //expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{17-17= [self] in}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{17-17= [self] in}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{17-17= [self] in}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{17-17= [self] in}}
       func inner() { foo() }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{22-22=self.}}
-      let inner2 = { foo() }  // expected-warning {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{21-21= [self] in}} expected-note{{reference 'self.' explicitly}} {{22-22=self.}}
+      let inner2 = { foo() }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{21-21= [self] in}} expected-note{{reference 'self.' explicitly}} {{22-22=self.}}
       _ = inner2
       func multi() -> Int { foo(); return 0 }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{29-29=self.}}
       let multi2: () -> Int = { foo(); return 0 }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{32-32= [self] in}} expected-note{{reference 'self.' explicitly}} {{33-33=self.}}
       _ = multi2
-      doesEscape { foo() }  // expected-warning {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{19-19= [self] in}} expected-note{{reference 'self.' explicitly}} {{20-20=self.}}
+      doesEscape { foo() }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{19-19= [self] in}} expected-note{{reference 'self.' explicitly}} {{20-20=self.}}
       takesNoEscapeClosure { foo() }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{30-30=self.}}
       doesEscape { foo(); return 0 }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{19-19= [self] in}} expected-note{{reference 'self.' explicitly}} {{20-20=self.}}
       takesNoEscapeClosure { foo(); return 0 }  // expected-error {{call to method 'foo' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{reference 'self.' explicitly}} {{30-30=self.}}

test/expr/closure/closures.swift

@@ -172,7 +172,7 @@ class ExplicitSelfRequiredTest {
     doStuff({ [unowned(unsafe) self] in x+1 })
     doStuff({ [unowned self = self] in x+1 })
     doStuff({ x+1 })    // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{14-14= [self] in}} expected-note{{reference 'self.' explicitly}} {{15-15=self.}}
-    doVoidStuff({ doStuff({ x+1 })}) // expected-warning {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{28-28= [self] in}} expected-note{{reference 'self.' explicitly}} {{29-29=self.}}
+    doVoidStuff({ doStuff({ x+1 })}) // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{28-28= [self] in}} expected-note{{reference 'self.' explicitly}} {{29-29=self.}}
     doVoidStuff({ x += 1 })    // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{18-18= [self] in}} expected-note{{reference 'self.' explicitly}} {{19-19=self.}}
     doVoidStuff({ _ = "\(x)"}) // expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{18-18= [self] in}} expected-note{{reference 'self.' explicitly}} {{26-26=self.}}
     doVoidStuff({ [y = self] in x += 1 }) // expected-warning {{capture 'y' was never used}} expected-error {{reference to property 'x' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note{{capture 'self' explicitly to enable implicit 'self' in this closure}} {{20-20=self, }} expected-note{{reference 'self.' explicitly}} {{33-33=self.}}
@@ -694,3 +694,18 @@ func testSR13239_Variadic_Twos() -> Int {
     print("hello")
   })
 }
+
+// rdar://82545600: this should just be a warning until Swift 6
+public class TestImplicitCaptureOfExplicitCaptureOfSelfInEscapingClosure {
+    var property = false
+
+    private init() {
+        doVoidStuff { [unowned self] in
+            doVoidStuff {}
+            doVoidStuff { // expected-note {{capture 'self' explicitly to enable implicit 'self' in this closure}}
+                doVoidStuff {}
+                property = false // expected-warning {{reference to property 'property' in closure requires explicit use of 'self' to make capture semantics explicit}} expected-note {{reference 'self.' explicitly}}
+            }
+        }
+    }
+}