[ClangImporter] Don't import compatibility methods named 'print'. (#10928)

...because they make things harder for people trying to use
Swift.print. Before:

  error: 'print' has been renamed to 'printDocument(_:)'

After:

  error: use of 'print' nearly matches global function
    'print(_:separator:terminator:)' in module 'Swift'
    rather than instance method 'print(_:extra:)'

(This actually occurs with AppKit's NSDocument, so it's not just a
hypothetical concern.)

rdar://problem/32839733

lib/ClangImporter/ImportDecl.cpp

@@ -1868,6 +1868,23 @@ applyPropertyOwnership(VarDecl *prop,
   }
 }
 
+/// Does this name refer to a method that might shadow Swift.print?
+///
+/// As a heuristic, methods that have a base name of 'print' but more than
+/// one argument are left alone. These can still shadow Swift.print but are
+/// less likely to be confused for it, at least.
+static bool isPrintLikeMethod(DeclName name, const DeclContext *dc) {
+  if (!name || name.isSpecial() || name.isSimpleName())
+    return false;
+  if (name.getBaseIdentifier().str() != "print")
+    return false;
+  if (!dc->isTypeContext())
+    return false;
+  if (name.getArgumentNames().size() > 1)
+    return false;
+  return true;
+}
+
 using MirroredMethodEntry =
   std::pair<const clang::ObjCMethodDecl*, ProtocolDecl*>;
 
@@ -3681,6 +3698,14 @@ namespace {
       if (forceClassMethod && decl->hasRelatedResultType())
         return nullptr;
 
+      // Hack: avoid importing methods named "print" that aren't available in
+      // the current version of Swift. We'd rather just let the user use
+      // Swift.print in that case.
+      if (!isActiveSwiftVersion() &&
+          isPrintLikeMethod(importedName.getDeclName(), dc)) {
+        return nullptr;
+      }
+
       // Add the implicit 'self' parameter patterns.
       bool isInstance = decl->isInstanceMethod() && !forceClassMethod;
       SmallVector<ParameterList *, 4> bodyParams;
@@ -7114,15 +7139,10 @@ void ClangImporter::Implementation::importAttributes(
   // Hack: mark any method named "print" with less than two parameters as
   // warn_unqualified_access.
   if (auto MD = dyn_cast<FuncDecl>(MappedDecl)) {
-    if (!MD->getName().empty() && MD->getName().str() == "print" &&
+    if (isPrintLikeMethod(MD->getFullName(), MD->getDeclContext())) {
-        MD->getDeclContext()->isTypeContext()) {
+      // Use a non-implicit attribute so it shows up in the generated
-      auto *formalParams = MD->getParameterList(1);
+      // interface.
-      if (formalParams->size() <= 1) {
+      MD->getAttrs().add(new (C) WarnUnqualifiedAccessAttr(/*implicit*/false));
-        // Use a non-implicit attribute so it shows up in the generated
-        // interface.
-        MD->getAttrs().add(
-            new (C) WarnUnqualifiedAccessAttr(/*implicit*/false));
-      }
     }
   }
 

test/APINotes/Inputs/custom-frameworks/APINotesFrameworkTest.framework/Headers/APINotesFrameworkTest.apinotes

@@ -2,6 +2,31 @@ Name: APINotesFrameworkTest
 Classes:
   - Name: A
     SwiftObjCMembers: true
+  - Name: PrintingInterference
+    Methods:
+      - Selector: 'print:'
+        MethodKind: Instance
+        SwiftName: 'printDocument(_:)'
+  - Name: PrintingRenamed
+    Methods:
+      - Selector: 'print'
+        MethodKind: Instance
+        SwiftName: 'printDocument()'
+      - Selector: 'print:'
+        MethodKind: Instance
+        SwiftName: 'printDocument(_:)'
+      - Selector: 'print:options:'
+        MethodKind: Instance
+        SwiftName: 'printDocument(_:options:)'
+      - Selector: 'print'
+        MethodKind: Class
+        SwiftName: 'printDocument()'
+      - Selector: 'print:'
+        MethodKind: Class
+        SwiftName: 'printDocument(_:)'
+      - Selector: 'print:options:'
+        MethodKind: Class
+        SwiftName: 'printDocument(_:options:)'
   - Name: TestProperties
     Properties:
       - Name: accessorsOnly
@@ -43,6 +68,31 @@ Tags:
 SwiftVersions:
   - Version: 3.0
     Classes:
+      - Name: PrintingInterference
+        Methods:
+          - Selector: 'print:'
+            MethodKind: Instance
+            SwiftName: 'print(_:)'
+      - Name: PrintingRenamed
+        Methods:
+          - Selector: 'print'
+            MethodKind: Instance
+            SwiftName: 'print()'
+          - Selector: 'print:'
+            MethodKind: Instance
+            SwiftName: 'print(_:)'
+          - Selector: 'print:options:'
+            MethodKind: Instance
+            SwiftName: 'print(_:options:)'
+          - Selector: 'print'
+            MethodKind: Class
+            SwiftName: 'print()'
+          - Selector: 'print:'
+            MethodKind: Class
+            SwiftName: 'print(_:)'
+          - Selector: 'print:options:'
+            MethodKind: Class
+            SwiftName: 'print(_:options:)'
       - Name: TestProperties
         Methods:
           - Selector: accessorsOnlyRenamedRetyped

test/APINotes/Inputs/custom-frameworks/APINotesFrameworkTest.framework/Headers/Classes.h

@@ -17,5 +17,20 @@
 @property (nullable) id importantInstanceProperty __attribute__((swift_name("finalInstanceProperty")));
 @end
 
+@interface PrintingRenamed : Base
+- (void)print;
+- (void)print:(id)thing;
+- (void)print:(id)thing options:(id)options;
+
++ (void)print;
++ (void)print:(id)thing;
++ (void)print:(id)thing options:(id)options;
+@end
+
+@interface PrintingInterference : Base
+- (void)print:(id)thing; // Only this one gets renamed.
+- (void)print:(id)thing extra:(id)options;
+@end
+
 #pragma clang assume_nonnull end
 #endif // __OBJC__

test/APINotes/versioned-objc.swift

@@ -140,4 +140,46 @@ func testRenamedProtocolMembers(obj: ProtoWithManyRenames) {
   // CHECK-DIAGS-4-NOT: :[[@LINE-1]]:{{[0-9]+}}:
 }
 
+extension PrintingRenamed {
+  func testDroppingRenamedPrints() {
+    // CHECK-DIAGS-3: [[@LINE+1]]:{{[0-9]+}}: warning: use of 'print' treated as a reference to instance method
+    print()
+    // CHECK-DIAGS-4-NOT: [[@LINE-1]]:{{[0-9]+}}:
+
+    // CHECK-DIAGS-3: [[@LINE+1]]:{{[0-9]+}}: warning: use of 'print' treated as a reference to instance method
+    print(self)
+    // CHECK-DIAGS-4-NOT: [[@LINE-1]]:{{[0-9]+}}:
+
+    // CHECK-DIAGS-3-NOT: [[@LINE+1]]:{{[0-9]+}}:
+    print(self, options: self)
+    // CHECK-DIAGS-4: [[@LINE-1]]:{{[0-9]+}}: error: argument labels '(_:, options:)' do not match any available overloads
+  }
+
+  static func testDroppingRenamedPrints() {
+    // CHECK-DIAGS-3: [[@LINE+1]]:{{[0-9]+}}: warning: use of 'print' treated as a reference to class method
+    print()
+    // CHECK-DIAGS-4-NOT: [[@LINE-1]]:{{[0-9]+}}:
+
+    // CHECK-DIAGS-3: [[@LINE+1]]:{{[0-9]+}}: warning: use of 'print' treated as a reference to class method
+    print(self)
+    // CHECK-DIAGS-4-NOT: [[@LINE-1]]:{{[0-9]+}}:
+
+    // CHECK-DIAGS-3-NOT: [[@LINE+1]]:{{[0-9]+}}:
+    print(self, options: self)
+    // CHECK-DIAGS-4: [[@LINE-1]]:{{[0-9]+}}: error: argument labels '(_:, options:)' do not match any available overloads
+  }
+}
+
+extension PrintingInterference {
+  func testDroppingRenamedPrints() {
+    // CHECK-DIAGS-3: [[@LINE+1]]:{{[0-9]+}}: warning: use of 'print' treated as a reference to instance method
+    print(self)
+    // CHECK-DIAGS-4: [[@LINE-1]]:{{[0-9]+}}: error: use of 'print' nearly matches global function 'print(_:separator:terminator:)' in module 'Swift' rather than instance method 'print(_:extra:)'
+
+    // CHECK-DIAGS-3-NOT: [[@LINE+1]]:{{[0-9]+}}:
+    print(self, extra: self)
+    // CHECK-DIAGS-4-NOT: [[@LINE-1]]:{{[0-9]+}}:
+  }
+}
+
 let unrelatedDiagnostic: Int = nil