Fix a bug found by inspection and add some regression tests

lib/Sema/CSApply.cpp

@@ -4748,31 +4748,10 @@ Expr *ExprRewriter::coerceExistential(Expr *expr, Type toType,
                                       cs.getType(result)));
   }
 
-  // If the type we are trying to coerce is a tuple, let's look through
-  // its elements to see if there are any LValue types present, such requires
-  // load or address-of operation first before proceeding with erasure.
+  // Load tuples with lvalue elements.
   if (auto tupleType = fromType->getAs<TupleType>()) {
-    bool coerceToRValue = false;
-    for (auto element : tupleType->getElements()) {
-      if (element.getType()->is<LValueType>()) {
-        coerceToRValue = true;
-        break;
-      }
-    }
-
-    // Tuple has one or more LValue types associated with it,
-    // which requires coercion to RValue, let's perform it here by creating
-    // new tuple type with LValue(s) stripped off and coercing
-    // expression to that type, which would do required transformation.
-    if (coerceToRValue) {
-      SmallVector<TupleTypeElt, 2> elements;
-      for (auto &element : tupleType->getElements())
-        elements.push_back(TupleTypeElt(element.getType()->getRValueType(),
-                                        element.getName(),
-                                        element.getParameterFlags()));
-
-      // New type is guaranteed to be a tuple because source type is one.
-      auto toTuple = TupleType::get(elements, ctx)->castTo<TupleType>();
+    if (tupleType->isLValueType()) {
+      auto toTuple = tupleType->getRValueType()->castTo<TupleType>();
       SmallVector<int, 4> sources;
       SmallVector<unsigned, 4> variadicArgs;
       bool failed = computeTupleShuffle(tupleType, toTuple,

test/Constraints/tuple.swift

@@ -202,3 +202,14 @@ func f(a : r25271859<(Float, Int)>) {
   }
 }
 
+// LValue to rvalue conversions.
+
+func takesRValue(_: (Int, (Int, Int))) {}
+func takesAny(_: Any) {}
+
+var x = 0
+var y = 0
+
+let _ = (x, (y, 0))
+takesRValue((x, (y, 0)))
+takesAny((x, (y, 0)))

validation-test/IDE/crashers_2/0001-complete-typeloc-in-generic-signature.swift

@@ -0,0 +1,6 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+func matched<C: Collection>(atStartOf c: C)
+  where C.Index#^A^# == Index {
+}

validation-test/IDE/crashers_2/0002-complete-unbound-generic-type.swift

@@ -0,0 +1,4 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+let bounds: Range#^A^#

validation-test/IDE/crashers_2/0003-complete-default-argument-closure.swift

@@ -0,0 +1,4 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+func searchTest(format: ()->String = { "" }#^A^#) {}

validation-test/IDE/crashers_2/0004-unmapped-dependent-type.swift

@@ -0,0 +1,8 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+func _thread() {
+  _ = #^A^#
+}
+
+func run<InputCollection : Collection, Result>(_: InputCollection) -> Result {}

validation-test/IDE/crashers_2/0005-should-have-found-non-type-context-by-now.swift

@@ -0,0 +1,22 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A1 -source-filename=%s
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=B1 -source-filename=%s
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=C1 -source-filename=%s
+
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A2 -source-filename=%s
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=B2 -source-filename=%s
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=C2 -source-filename=%s
+
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A3 -source-filename=%s
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=B3 -source-filename=%s
+// REQUIRES: asserts
+
+class a1<b#^A1^#> {}
+struct a2<b#^B1^#> {}
+enum a3<b#^C1^#> {}
+
+class a4<b> where c == b#^A2^# {}
+struct a5<b> where c == b#^B2^# {}
+enum a6<b> where c == b#^C2^# {}yt
+
+func f1<b#^A3^#> {}
+func f2<b>() where c == b#^B3^# {}

validation-test/IDE/crashers_2/0006-crazy-associated-types.swift

@@ -0,0 +1,12 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+protocol a {
+  associatedtype b
+}
+protocol c {
+  associatedtype d : a
+}
+
+struct e<f : c> where f == f.g.b {
+  #^A^#

validation-test/IDE/crashers_2/0007-archetype-not-in-context.swift

@@ -0,0 +1,11 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+class D<X, Y>() {}
+
+class C<T> {
+  func f<U>() -> D<U, T> {}
+  func g() {
+    f#^A^#
+  }
+}

validation-test/IDE/crashers_2/0008-must-conform-to-literal-protocol.swift

@@ -0,0 +1,4 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+.a != nil #^A^#

validation-test/IDE/crashers_2/0010-reference-to-self-in-extension-init.swift

@@ -0,0 +1,7 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+extension Integer { 
+#^A^#
+  extension {
+        var : Self   

validation-test/IDE/crashers_2/0011-complete-protocol-with-initializer.swift

@@ -0,0 +1,4 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+Integer#^A^#

validation-test/IDE/crashers_2/0012-protocol-where-clause.swift

@@ -0,0 +1,4 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+protocol a where #^A^#

validation-test/IDE/crashers_2/0013-unmapped-dependent-type-2.swift

@@ -0,0 +1,6 @@
+// RUN: not --crash %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+// REQUIRES: asserts
+
+func a<b>(() -> b) -> b {
+  a {}#^A^#
+}

validation-test/IDE/crashers_2_fixed/0009-protocol-extension-self-assign.swift

@@ -0,0 +1,7 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+
+extension Integer {
+  init() {
+    self = #^A^#
+  }
+}

validation-test/IDE/crashers_2_fixed/0014-sr4560.swift

@@ -0,0 +1,14 @@
+// RUN: %target-swift-ide-test -code-completion -code-completion-token=A -source-filename=%s
+
+protocol MyDelegate: AnyObject {
+	func mySweetDelegateFunction()
+}
+
+class Foo {
+	weak var delegate: MyDelegate?
+
+	func bar() {
+		self.delegate.#^A^#
+			// ^--- type "." here -> crash
+	}
+}