merge recovery-2.c into recovery-3.c.

Substantially improve error recovery after broken if conditions by
parsing the full if when we have a semantic error instead of using
parser recovery techniques to recover from a semantic error.

This fixes rdar://6094870 - spurious error after invalid 'if' condition

llvm-svn: 60929

clang/lib/Parse/ParseStmt.cpp

@@ -448,20 +448,28 @@ Parser::OwningStmtResult Parser::ParseIfStatement() {
   ParseScope IfScope(this, Scope::DeclScope | Scope::ControlScope, C99orCXX);
 
   // Parse the condition.
-  OwningExprResult CondExp(Actions);
-  if (getLang().CPlusPlus) {
   SourceLocation LParenLoc = ConsumeParen();
-    CondExp = ParseCXXCondition();
-    MatchRHSPunctuation(tok::r_paren, LParenLoc);
-  } else {
-    CondExp = ParseSimpleParenExpression();
-  }
   
-  if (CondExp.isInvalid()) {
+  OwningExprResult CondExp(Actions);
+  if (getLang().CPlusPlus)
+    CondExp = ParseCXXCondition();
+  else
+    CondExp = ParseExpression();
+  
+  // If the parser was confused by the condition and we don't have a ')', try to
+  // recover by skipping ahead to a semi and bailing out.  If condexp is
+  // semantically invalid but we have well formed code, keep going.
+  if (CondExp.isInvalid() && Tok.isNot(tok::r_paren)) {
     SkipUntil(tok::semi);
+    // Skipping may have stopped if it found the containing ')'.  If so, we can
+    // continue parsing the if statement.
+    if (Tok.isNot(tok::r_paren))
       return StmtError();
   }
   
+  // Otherwise the condition is valid or the rparen is present.
+  MatchRHSPunctuation(tok::r_paren, LParenLoc);
+
   // C99 6.8.4p3 - In C99, the body of the if statement is a scope, even if
   // there is no compound stmt.  C90 does not have this clause.  We only do this
   // if the body isn't a compound statement to avoid push/pop in common cases.
@@ -522,6 +530,11 @@ Parser::OwningStmtResult Parser::ParseIfStatement() {
 
   IfScope.Exit();
   
+  // If the condition was invalid, discard the if statement.  We could recover
+  // better by replacing it with a valid expr, but don't do that yet.
+  if (CondExp.isInvalid())
+    return StmtError();
+
   // If the then or else stmt is invalid and the other is valid (and present),
   // make turn the invalid one into a null stmt to avoid dropping the other 
   // part.  If both are invalid, return error.

clang/test/Parser/recovery-2.c

@@ -1,8 +0,0 @@
-// RUN: clang -fsyntax-only -verify -pedantic %s
-
-
-// PR2241
-float f[] = { 
-  1e,            // expected-error {{exponent}}
-  1ee0           // expected-error {{exponent}}
-};

clang/test/Parser/recovery-3.c

@@ -1,5 +1,12 @@
 // RUN: clang -fsyntax-only -verify -pedantic %s
 
+// PR2241
+float test2241[] = { 
+  1e,            // expected-error {{exponent}}
+  1ee0           // expected-error {{exponent}}
+};
+
+
 // Testcase derived from PR2692
 static char *f (char * (*g) (char **, int), char **p, ...) {
     char *s;
@@ -12,3 +19,28 @@ static char *f (char * (*g) (char **, int), char **p, ...) {
 } // expected-error {{expected external declaration}}
 
 
+// rdar://6094870
+int test(int) {
+  struct { int i; } x;
+  
+  if (x.hello)   // expected-error {{no member named 'hello'}}
+    test(0);
+  else
+    ;
+  
+  if (x.hello == 0)   // expected-error {{no member named 'hello'}}
+    test(0);
+  else
+    ;
+  
+  if ((x.hello == 0))   // expected-error {{no member named 'hello'}}
+    test(0);
+  else
+    ;
+  
+  if (x.i == 0))   // expected-error {{expected expression}}
+    test(0);
+  else
+    ;
+}
+