Fix method call type inference with explicit type parameters.

pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart

Index: pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
index 73c98cc0ed765e42978d4ff155b6b30106497f2d..1d39d0e0e14f9e9fa3092fc7b919dfc3ef829355 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
@@ -454,9 +454,10 @@ abstract class TypeInferrerImpl<S, E, V, F> extends TypeInferrer<S, E, V, F> {
           Substitution.fromPairs(memberTypeParameters, inferredTypes);
       formalTypes = [];
       actualTypes = [];
-    } else if (explicitTypeArguments != null) {
+    } else if (explicitTypeArguments != null &&
+        memberTypeParameters.length == explicitTypeArguments.length) {
       substitution =
-          Substitution.fromPairs(memberTypeParameters, inferredTypes);
+          Substitution.fromPairs(memberTypeParameters, explicitTypeArguments);
     }
     int i = 0;
     forEachArgument((name, expression) {