Fix parse error when apply is at eof

smithy-model/src/main/java/software/amazon/smithy/model/loader/SmithyModelLoader.java

@@ -301,7 +301,7 @@ private static void parse(State state) {
             if (token.type == UNQUOTED) {
                 parseStatement(token, state);
             } else if (token.type == ANNOTATION) {
-                state.pendingTraits.add(parseTraitValue(token, state, false));
+                state.pendingTraits.add(parseTraitValue(token, state, TraitValueType.SHAPE));
             } else if (token.type == CONTROL) {
                 parseControlStatement(state, token);
             } else if (token.type == DOC) {
@@ -386,22 +386,32 @@ private static void requireNamespaceOrThrow(State state) {
         }
     }
 
-    private static Pair<String, Node> parseTraitValue(Token token, State state, boolean memberScope) {
+    private enum TraitValueType { SHAPE, MEMBER, APPLY }
+
+    private static Pair<String, Node> parseTraitValue(Token token, State state, TraitValueType type) {
         try {
             requireNamespaceOrThrow(state);
 
             // Resolve the trait name and ensure that the trait forms a syntactically valid value.
             ShapeId.fromOptionalNamespace(state.visitor.getNamespace(), token.lexeme);
             Pair<String, Node> result = Pair.of(token.lexeme, parseTraitValueBody(state));
 
+            // `apply` doesn't require any specific token to follow.
+            if (type == TraitValueType.APPLY) {
+                return result;
+            }
+
+            // Other kinds of trait values require an annotation or definition to follow.
             if (!state.peek().isPresent()) {
                 throw state.syntax("Found a trait doesn't apply to anything");
             }
 
             Token next = state.peek().get();
-            if (next.type != ANNOTATION
-                && (next.type != UNQUOTED || (!memberScope && !SUPPORTS_TRAITS.contains(next.lexeme)))) {
-                throw state.syntax("Traits cannot be applied to `" + next.lexeme + "`");
+            if (next.type != ANNOTATION) {
+                if (next.type != UNQUOTED
+                    || (type != TraitValueType.MEMBER && !SUPPORTS_TRAITS.contains(next.lexeme))) {
+                    throw state.syntax("Traits cannot be applied to `" + next.lexeme + "`");
+                }
             }
 
             return result;
@@ -572,7 +582,7 @@ private static void parseStructuredContents(
         Token token = state.expect(ANNOTATION, QUOTED, UNQUOTED, RBRACE, DOC);
         while (token.type != RBRACE) {
             if (token.type == ANNOTATION) {
-                memberTraits.add(parseTraitValue(token, state, true));
+                memberTraits.add(parseTraitValue(token, state, TraitValueType.MEMBER));
                 // Traits can't come before a closing brace, so continue
                 // to make sure they come before another trait or a key.
             } else if (token.type == DOC) {
@@ -659,7 +669,7 @@ private static void parseApply(State state) {
         String name = state.expect(UNQUOTED).lexeme;
         ShapeId id = ShapeId.fromOptionalNamespace(state.visitor.getNamespace(), name);
         Token token = state.expect(ANNOTATION);
-        Pair<String, Node> trait = parseTraitValue(token, state, false);
+        Pair<String, Node> trait = parseTraitValue(token, state, TraitValueType.APPLY);
         state.visitor.onTrait(id, trait.getLeft(), trait.getRight());
         state.expectNewline();
     }

smithy-model/src/test/resources/software/amazon/smithy/model/loader/valid/traits.json

@@ -23,7 +23,8 @@
       },
       "E": {
         "type": "string",
-        "smithy.api#documentation": "Hello!"
+        "smithy.api#documentation": "Hello!",
+        "smithy.api#deprecated": {}
       },
       "F": {
         "type": "string",

smithy-model/src/test/resources/software/amazon/smithy/model/loader/valid/traits.smithy

@@ -129,3 +129,5 @@ string T
     many
     lines.""")
 string U
+
+apply E @deprecated