[QoI] Cleanup AST after trying to shrink constraint system of invalid expression

Since `ConstraintSystem::shrink` is going to attempt to type-check
sub-expressions separately it's essential to clean-up AST if constraint
generation or solving of the such expressions fails, otherwise if
such solving resulted in creation of implicit expression type variables
might leak to the outside.

Author: xedin

lib/Sema/CSSolver.cpp

@@ -1453,6 +1453,7 @@ bool ConstraintSystem::Candidate::solve() {
   // because it would assign types to expressions, which
   // might interfere with solving higher-level expressions.
   ExprCleaner cleaner(E);
+  CleanupIllFormedExpressionRAII cleanup(TC.Context, E);
 
   // Allocate new constraint system for sub-expression.
   ConstraintSystem cs(TC, DC, None);
@@ -1495,6 +1496,18 @@ bool ConstraintSystem::Candidate::solve() {
 
   // Record found solutions as suggestions.
   this->applySolutions(solutions);
+
+  // Solution application is going to modify AST, so we need to avoid
+  // clean-up, but let's double-check if we have any implicit
+  // expressions with type variables and nullify their types.
+  cleanup.disable();
+  E->forEachChildExpr([&](Expr *childExpr) -> Expr * {
+    Type type = childExpr->getType();
+    if (childExpr->isImplicit() && type && type->hasTypeVariable())
+      childExpr->setType(Type());
+    return childExpr;
+  });
+
   return false;
 }
 

validation-test/compiler_crashers/28593-unreachable-executed-at-swift-lib-ast-type-cpp-3771.swift renamed to validation-test/compiler_crashers_fixed/28593-unreachable-executed-at-swift-lib-ast-type-cpp-3771.swift

@@ -5,6 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 [{_=#keyPath(t>w

validation-test/compiler_crashers/28623-swift-tupletype-get-llvm-arrayref-swift-tupletypeelt-swift-astcontext-const.swift renamed to validation-test/compiler_crashers_fixed/28623-swift-tupletype-get-llvm-arrayref-swift-tupletypeelt-swift-astcontext-const.swift

@@ -5,6 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 f#keyPath(n&_==a>c{{{{{{{{{{{{{{{{{_=b:{{{{c{{{{{{d

validation-test/compiler_crashers/28631-unreachable-executed-at-swift-lib-ast-type-cpp-1130.swift renamed to validation-test/compiler_crashers_fixed/28631-unreachable-executed-at-swift-lib-ast-type-cpp-1130.swift

@@ -5,6 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 [{{{{{{{{{{{{{{0=#keyPath(n&_=d

validation-test/compiler_crashers/28632-unreachable-executed-at-swift-lib-ast-type-cpp-1130.swift renamed to validation-test/compiler_crashers_fixed/28632-unreachable-executed-at-swift-lib-ast-type-cpp-1130.swift

@@ -5,9 +5,8 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
 // REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 
 {func a>
 print(a==#keyPath(a{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{{

validation-test/compiler_crashers/28635-swift-tupletype-get-llvm-arrayref-swift-tupletypeelt-swift-astcontext-const.swift renamed to validation-test/compiler_crashers_fixed/28635-swift-tupletype-get-llvm-arrayref-swift-tupletypeelt-swift-astcontext-const.swift

@@ -5,7 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
-// REQUIRES: deterministic-behavior
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 func a|Set(#keyPath(t>a>a{

validation-test/compiler_crashers/28639-unreachable-executed-at-swift-lib-ast-type-cpp-1337.swift renamed to validation-test/compiler_crashers_fixed/28639-unreachable-executed-at-swift-lib-ast-type-cpp-1337.swift

@@ -5,6 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 print([{#keyPath(a}(t>A

validation-test/compiler_crashers/28640-swift-tupletype-get-llvm-arrayref-swift-tupletypeelt-swift-astcontext-const.swift renamed to validation-test/compiler_crashers_fixed/28640-swift-tupletype-get-llvm-arrayref-swift-tupletypeelt-swift-astcontext-const.swift

@@ -5,6 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 protocol a func a|Set(#keyPath(t>a{

validation-test/compiler_crashers/28641-result-case-not-implemented.swift renamed to validation-test/compiler_crashers_fixed/28641-result-case-not-implemented.swift

@@ -5,7 +5,6 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
 // REQUIRES: asserts
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 {let β=b&[{{{#keyPath(n&[{{{{{{{{{{{{{{{{{{{{{{{{{{a{{{{s

validation-test/compiler_crashers/28642-swift-optionaltype-get-swift-type.swift renamed to validation-test/compiler_crashers_fixed/28642-swift-optionaltype-get-swift-type.swift

@@ -5,6 +5,5 @@
 // See https://swift.org/LICENSE.txt for license information
 // See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
 
-// REQUIRES: deterministic-behavior
-// RUN: not --crash %target-swift-frontend %s -emit-ir
+// RUN: not %target-swift-frontend %s -emit-ir
 Array(_==#keyPath(t>Void!