Merge pull request #83704 from hamishknight/fix-stress-tester-regression

[CS] Record `SkipUnhandledConstructInResultBuilder` for completion

Author: hamishknight

lib/Sema/BuilderTransform.cpp

@@ -1153,13 +1153,6 @@ ConstraintSystem::matchResultBuilder(AnyFunctionRef fn, Type builderType,
     if (auto unsupported = transform.getUnsupportedElement()) {
       assert(!body);
 
-      // If we're solving for code completion and the body contains the code
-      // completion location, fall back to solving as a regular function body.
-      if (isForCodeCompletion() &&
-          containsIDEInspectionTarget(fn.getBody())) {
-        return std::nullopt;
-      }
-
       // If we aren't supposed to attempt fixes, fail.
       if (!shouldAttemptFixes()) {
         return getTypeMatchFailure(locator);
@@ -1173,6 +1166,13 @@ ConstraintSystem::matchResultBuilder(AnyFunctionRef fn, Type builderType,
         return getTypeMatchFailure(locator);
       }
 
+      // If we're solving for code completion and the body contains the code
+      // completion location, fall back to solving as a regular function body.
+      if (isForCodeCompletion() &&
+          containsIDEInspectionTarget(fn.getBody())) {
+        return std::nullopt;
+      }
+
       if (auto *closure =
               getAsExpr<ClosureExpr>(fn.getAbstractClosureExpr())) {
         recordTypeVariablesAsHoles(getClosureType(closure));

test/IDE/pr-83704.swift

@@ -0,0 +1,102 @@
+// RUN: %batch-code-completion
+
+@resultBuilder
+struct Builder0 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+  static func buildArray<T>(_ components: [T]) -> T { components.first! }
+}
+@resultBuilder
+struct Builder1 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder2 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder3 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder4 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder5 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder6 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder7 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder8 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+@resultBuilder
+struct Builder9 {
+  static func buildBlock<T>(_ x: T) -> T { x }
+}
+
+protocol P0 {}
+protocol P1 {}
+protocol P2 {}
+protocol P3 {}
+protocol P4 {}
+protocol P5 {}
+protocol P6 {}
+protocol P7 {}
+protocol P8 {}
+protocol P9 {}
+
+struct S<T> {}
+extension S: P0 where T : P0 { init<U>(@Builder0 fn: () -> U) {} }
+extension S: P1 where T : P1 { init<U>(@Builder1 fn: () -> U) {} }
+extension S: P2 where T : P2 { init<U>(@Builder2 fn: () -> U) {} }
+extension S: P3 where T : P3 { init<U>(@Builder3 fn: () -> U) {} }
+extension S: P4 where T : P4 { init<U>(@Builder4 fn: () -> U) {} }
+extension S: P5 where T : P5 { init<U>(@Builder5 fn: () -> U) {} }
+extension S: P6 where T : P6 { init<U>(@Builder6 fn: () -> U) {} }
+extension S: P7 where T : P7 { init<U>(@Builder7 fn: () -> U) {} }
+extension S: P8 where T : P8 { init<U>(@Builder8 fn: () -> U) {} }
+extension S: P9 where T : P9 { init<U>(@Builder9 fn: () -> U) {} }
+
+struct K {
+  var foo: Int
+}
+
+// Make sure we ignore all the result builders that cannot handle for loops
+// and just use Builder0. There's also no way 'T' can be inferred here but
+// that doesn't really matter for this test.
+func foo(_ ks: [K]) {
+  S {
+    for k0 in ks {
+      S {
+        for k1 in ks {
+          S {
+            for k2 in ks {
+              S {
+                for k3 in ks {
+                  S {
+                    for k4 in ks {
+                      S {
+                        for k5 in ks {
+                          k5.#^COMPLETE^#
+                          // COMPLETE: Decl[InstanceVar]/CurrNominal: foo[#Int#]; name=foo
+                        }
+                      }
+                    }
+                  }
+                }
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}