Do not apply var where the declaration cannot legally carry it

src/main/java/org/openrewrite/java/migrate/lang/var/DeclarationCheck.java

@@ -48,13 +48,25 @@ final class DeclarationCheck {
      * @return true if var is applicable in general
      */
     public static boolean isVarApplicable(Cursor cursor, J.VariableDeclarations vd) {
-        if (isField(vd, cursor) || isMethodParameter(vd, cursor) || !isSingleVariableDefinition(vd) || initializedByTernary(vd)) {
+        if (isField(vd, cursor) || isMethodParameter(vd, cursor) || !isSingleVariableDefinition(vd) ||
+                initializedByTernary(vd) || hasDimensionsAfterName(vd)) {
             return false;
         }
 
         return isInsideMethod(cursor) || isInsideInitializer(cursor, 0);
     }
 
+    /**
+     * Determine whether the declarator carries C-style array brackets after the variable name, as in {@code int a[]}.
+     * JLS 14.4.1 makes extra array dimensions on a {@code var} declarator a compile-time error.
+     *
+     * @param vd variable definition at hand
+     * @return true iff the variable name is followed by array dimensions
+     */
+    private static boolean hasDimensionsAfterName(J.VariableDeclarations vd) {
+        return !vd.getVariables().get(0).getDimensionsAfterName().isEmpty();
+    }
+
     /**
      * Determine if a variable definition defines a single variable that is directly initialized with value different from null, which not make use of var.
      *

src/main/java/org/openrewrite/java/migrate/lang/var/UseVarForGenericMethodInvocations.java

@@ -87,6 +87,13 @@ public J.VariableDeclarations visitVariableDeclarations(J.VariableDeclarations v
                 return vd;
             }
 
+            // Only a qualified invocation can carry a type witness (JLS 15.12), so an unqualified call whose return
+            // type still mentions a type variable has no way to hold on to the type the declaration pinned down.
+            if (invocation.getSelect() == null && invocation.getTypeParameters() == null &&
+                    invocation.getMethodType() != null && containsGenericTypeVariable(invocation.getMethodType().getReturnType())) {
+                return vd;
+            }
+
             if (vd.getType() instanceof JavaType.FullyQualified) {
                 maybeRemoveImport((JavaType.FullyQualified) vd.getType());
             }

src/test/java/org/openrewrite/java/migrate/lang/var/UseVarForGenericMethodInvocationsTest.java

@@ -56,6 +56,33 @@ void m() {
             );
         }
 
+        @Issue("https://github.com/openrewrite/rewrite-migrate-java/issues/1219")
+        @Test
+        void forUnqualifiedInvocationNeedingTypeWitness() {
+            // `var contentTypes = <T>contentType(...)` would not parse; a type witness needs a receiver
+            //language=java
+            rewriteRun(
+              version(
+                java("""
+                  package com.example.app;
+
+                  import java.util.function.Predicate;
+
+                  class A {
+                    static <T> Predicate<T> contentType(String... types) {
+                        return null;
+                    }
+                    static <T> Predicate<T> binary() {
+                        final Predicate<T> contentTypes = contentType("application/octet-stream");
+                        return contentTypes;
+                    }
+                  }
+                  """),
+                10
+              )
+            );
+        }
+
         @Nested
         class NotSupportedByOpenRewrite {
             // this is possible because `myList()`s type is fixed to `List<String>` but it is not distinguishable from

src/test/java/org/openrewrite/java/migrate/lang/var/UseVarForPrimitiveTest.java

@@ -18,6 +18,7 @@
 import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.openrewrite.DocumentExample;
+import org.openrewrite.Issue;
 import org.openrewrite.test.RecipeSpec;
 
 import static org.openrewrite.java.Assertions.java;
@@ -86,6 +87,25 @@ void m() {
             );
         }
 
+        @Issue("https://github.com/openrewrite/rewrite-migrate-java/issues/1218")
+        @Test
+        void forCStyleArrayDeclarator() {
+            //language=java
+            rewriteRun(
+              java(
+                """
+                  package com.example.app;
+
+                  class A {
+                    void m() {
+                        int address[] = new int[8];
+                    }
+                  }
+                  """
+              )
+            );
+        }
+
         @Test
         void forStringMethodCall() {
             //language=java