KT-847 Allow "this" without {} in string templates

compiler/frontend/src/org/jetbrains/jet/lang/parsing/JetExpressionParsing.java

@@ -1,9 +1,11 @@
 package org.jetbrains.jet.lang.parsing;
 
+import com.google.common.collect.ImmutableMap;
 import com.intellij.lang.PsiBuilder;
 import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.tree.TokenSet;
 import org.jetbrains.jet.JetNodeType;
+import org.jetbrains.jet.lexer.JetToken;
 import org.jetbrains.jet.lexer.JetTokens;
 
 import java.util.*;
@@ -18,6 +20,16 @@ public class JetExpressionParsing extends AbstractJetParsing {
     private static final TokenSet WHEN_CONDITION_RECOVERY_SET = TokenSet.create(RBRACE, IN_KEYWORD, NOT_IN, IS_KEYWORD, NOT_IS, ELSE_KEYWORD);
     private static final TokenSet WHEN_CONDITION_RECOVERY_SET_WITH_DOUBLE_ARROW = TokenSet.create(RBRACE, IN_KEYWORD, NOT_IN, IS_KEYWORD, NOT_IS, ELSE_KEYWORD, DOUBLE_ARROW, DOT);
 
+    private static final ImmutableMap<String, JetToken> KEYWORD_TEXTS = tokenSetToMap(KEYWORDS);
+
+    private static ImmutableMap<String, JetToken> tokenSetToMap(TokenSet tokens) {
+        ImmutableMap.Builder<String, JetToken> builder = ImmutableMap.builder();
+        for (IElementType token : tokens.getTypes()) {
+            builder.put(token.toString(), (JetToken) token);
+        }
+        return builder.build();
+    }
+
     private static final TokenSet TYPE_ARGUMENT_LIST_STOPPERS = TokenSet.create(
             INTEGER_LITERAL, FLOAT_LITERAL, CHARACTER_LITERAL, OPEN_QUOTE, RAW_STRING_LITERAL,
             NAMESPACE_KEYWORD, AS_KEYWORD, TYPE_KEYWORD, TRAIT_KEYWORD, CLASS_KEYWORD, THIS_KEYWORD, VAL_KEYWORD, VAR_KEYWORD,
@@ -587,7 +599,7 @@ public class JetExpressionParsing extends AbstractJetParsing {
     /*
      * stringTemplateElement
      *   : RegularStringPart
-     *   : ShortTemplateEntrySTART SimpleName
+     *   : ShortTemplateEntrySTART (SimpleName | "this")
      *   : EscapeSequence
      *   : longTemplate
      *   ;
@@ -611,9 +623,25 @@ public class JetExpressionParsing extends AbstractJetParsing {
             PsiBuilder.Marker entry = mark();
             advance(); // SHORT_TEMPLATE_ENTRY_START
 
-            PsiBuilder.Marker reference = mark();
-            expect(IDENTIFIER, "Expecting a name");
-            reference.done(REFERENCE_EXPRESSION);
+            if (at(THIS_KEYWORD)) {
+                PsiBuilder.Marker thisExpression = mark();
+                PsiBuilder.Marker reference = mark();
+                advance(); // THIS_KEYWORD
+                reference.done(REFERENCE_EXPRESSION);
+                thisExpression.done(THIS_EXPRESSION);
+            }
+            else {
+                JetToken keyword = KEYWORD_TEXTS.get(myBuilder.getTokenText());
+                if (keyword != null) {
+                    myBuilder.remapCurrentToken(keyword);
+                    errorAndAdvance("Keyword cannot be used as a reference");
+                }
+                else {
+                    PsiBuilder.Marker reference = mark();
+                    expect(IDENTIFIER, "Expecting a name");
+                    reference.done(REFERENCE_EXPRESSION);
+                }
+            }
 
             entry.done(SHORT_STRING_TEMPLATE_ENTRY);
         }

compiler/frontend/src/org/jetbrains/jet/lang/resolve/calls/CallResolver.java

@@ -59,7 +59,7 @@ public class CallResolver {
         JetSimpleNameExpression nameExpression = (JetSimpleNameExpression) calleeExpression;
         String referencedName = nameExpression.getReferencedName();
         if (referencedName == null) {
-            return null;
+            return OverloadResolutionResultsImpl.nameNotFound();
         }
         TaskPrioritizer<VariableDescriptor> task_prioritizer;
         if (nameExpression.getReferencedNameElementType() == JetTokens.FIELD_IDENTIFIER) {

compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/BasicExpressionTypingVisitor.java

@@ -916,7 +916,7 @@ public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
                 public void visitStringTemplateEntryWithExpression(JetStringTemplateEntryWithExpression entry) {
                     JetExpression entryExpression = entry.getExpression();
                     if (entryExpression != null) {
-                        facade.getType(entryExpression, context.replaceScope(context.scope));
+                        facade.getType(entryExpression, context);
                     }
                     value[0] = CompileTimeConstantResolver.OUT_OF_RANGE;
                 }

compiler/frontend/src/org/jetbrains/jet/lexer/Jet.flex

@@ -121,6 +121,10 @@ LONG_TEMPLATE_ENTRY_END=\}
                                             yypushback(yylength() - 1);
                                             return JetTokens.SHORT_TEMPLATE_ENTRY_START;
                                        }
+// Only *this* keyword is itself an expression valid in this position
+// *null*, *true* and *false* are also keywords and expression, but it does not make sense to put them
+// in a string template for it'd be easier to just type them in without a dollar
+<SHORT_TEMPLATE_ENTRY> "this"          { popState(); return JetTokens.THIS_KEYWORD; }
 <SHORT_TEMPLATE_ENTRY> {IDENTIFIER}    { popState(); return JetTokens.IDENTIFIER; }
 
 <STRING> {LONELY_DOLLAR}               { return JetTokens.REGULAR_STRING_PART; }

compiler/testData/diagnostics/tests/regressions/kt847.jet

@@ -0,0 +1,3 @@
+fun <T> T.mustBe(t : T) {
+    "$this must be$<!SYNTAX!>as<!>$t"
+}

compiler/testData/psi/StringTemplates.jet

@@ -7,6 +7,7 @@ fun demo() {
   fun buzz(f : fun () : Any?) : Int  = 1
   val sdf = 1
   val foo = 3;
+    "$this must be$as$t"
     "$abc"
     "$abc\"
     "$"

compiler/testData/psi/StringTemplates.txt

@@ -157,6 +157,25 @@ JetFile: StringTemplates.jet
             PsiElement(INTEGER_LITERAL)('3')
         PsiElement(SEMICOLON)(';')
         PsiWhiteSpace('\n    ')
+        STRING_TEMPLATE
+          PsiElement(OPEN_QUOTE)('"')
+          SHORT_STRING_TEMPLATE_ENTRY
+            PsiElement(SHORT_TEMPLATE_ENTRY_START)('$')
+            THIS_EXPRESSION
+              REFERENCE_EXPRESSION
+                PsiElement(this)('this')
+          LITERAL_STRING_TEMPLATE_ENTRY
+            PsiElement(REGULAR_STRING_PART)(' must be')
+          SHORT_STRING_TEMPLATE_ENTRY
+            PsiElement(SHORT_TEMPLATE_ENTRY_START)('$')
+            PsiErrorElement:Keyword cannot be used as a reference
+              PsiElement(as)('as')
+          SHORT_STRING_TEMPLATE_ENTRY
+            PsiElement(SHORT_TEMPLATE_ENTRY_START)('$')
+            REFERENCE_EXPRESSION
+              PsiElement(IDENTIFIER)('t')
+          PsiElement(CLOSING_QUOTE)('"')
+        PsiWhiteSpace('\n    ')
         STRING_TEMPLATE
           PsiElement(OPEN_QUOTE)('"')
           SHORT_STRING_TEMPLATE_ENTRY

grammar/src/expressions.grm

@@ -134,7 +134,7 @@ label
 
 literalConstant
   : "true" | "false"
-  : StringWithTemplates
+  : stringTemplate
   : NoEscapeString
   : IntegerLiteral
   : HexadecimalLiteral
@@ -143,6 +143,22 @@ literalConstant
   : "null"
   ;
 
+stringTemplate
+  : "\"" stringTemplateElement* "\""
+  ;
+
+stringTemplateElement
+  : RegularStringPart
+  : ShortTemplateEntrySTART (SimpleName | "this")
+  : EscapeSequence
+  : longTemplate
+  ;
+
+longTemplate
+  : "${" expression "}"
+  ;
+
+
 isRHS
   : pattern
   ;