[Refactoring] Only rename variables in capture lists once

Inside capture lists like `{ [test] in }`, `test` refers to both the newly declared, captured variable and the referenced variable it is initialized from. We currently try to rename it twice, yielding invalid, confusing results. Make sure to only record this situation once.

Fixes rdar://78522816 [SR-14661]

Author: ahoppen

lib/IDE/Refactoring.cpp

@@ -654,7 +654,22 @@ class RenameRangeCollector : public IndexDataConsumer {
   Action startSourceEntity(const IndexSymbol &symbol) override {
     if (symbol.USR == USR) {
       if (auto loc = indexSymbolToRenameLoc(symbol, newName)) {
-        locations.push_back(std::move(*loc));
+        // Inside capture lists like `{ [test] in }`, 'test' refers to both the
+        // newly declared, captured variable and the referenced variable it is
+        // initialized from. Make sure to only rename it once.
+        auto existingLoc = llvm::find_if(locations, [&](RenameLoc searchLoc) {
+          return searchLoc.Line == loc->Line && searchLoc.Column == loc->Column;
+        });
+        if (existingLoc == locations.end()) {
+          locations.push_back(std::move(*loc));
+        } else {
+          assert(existingLoc->OldName == loc->OldName &&
+                 existingLoc->NewName == loc->NewName &&
+                 existingLoc->IsFunctionLike == loc->IsFunctionLike &&
+                 existingLoc->IsNonProtocolType ==
+                     existingLoc->IsNonProtocolType &&
+                 "Asked to do a different rename for the same location?");
+        }
       }
     }
     return IndexDataConsumer::Continue;

test/refactoring/rename/Outputs/local/captured_variable.swift.expected

@@ -0,0 +1,57 @@
+func test1() {
+  if true {
+    let x = 1
+    print(x)
+  } else {
+    let x = 2
+    print(x)
+  }
+}
+
+func test2(arg1: Int?, arg2: (Int, String)?) {
+  if let x = arg1 {
+    print(x)
+  } else if let (x, y) = arg2 {
+    print(x, y)
+  }
+}
+
+func test3(arg: Int?) {
+  switch arg {
+  case let .some(x) where x == 0:
+    print(x)
+  case let .some(x) where x == 1,
+       let .some(x) where x == 2:
+    print(x)
+    fallthrough
+  case let .some(x) where x == 3:
+    print(x)
+  default:
+    break
+  }
+}
+
+struct Err1 : Error { }
+func test4(arg: () throws -> Void) {
+  do {
+    try arg()
+  } catch let x as Err1 {
+    print(x)
+  } catch let x {
+    print(x)
+  }
+}
+
+func test5(_ x: Int) {
+  let x = x 
+  print(x)
+}
+
+func testCaputreVariable() {
+  let capturedVariableRenamed = 0
+
+  _ = { [capturedVariableRenamed] in
+    print(capturedVariableRenamed)
+  }
+}
+

test/refactoring/rename/Outputs/local/casebind_1.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+

test/refactoring/rename/Outputs/local/casebind_2.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+

test/refactoring/rename/Outputs/local/catch_1.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+

test/refactoring/rename/Outputs/local/catch_2.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+

test/refactoring/rename/Outputs/local/ifbind_1.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+

test/refactoring/rename/Outputs/local/ifbind_2.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+

test/refactoring/rename/Outputs/local/localvar_1.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+

test/refactoring/rename/Outputs/local/localvar_2.swift.expected

@@ -47,3 +47,11 @@ func test5(_ x: Int) {
   print(x)
 }
 
+func testCaputreVariable() {
+  let capturedVariable = 0
+
+  _ = { [capturedVariable] in
+    print(capturedVariable)
+  }
+}
+