Remove the ability to produce an AST in presence of errors in --error-recovery mode

This reverts commit 7fd7cc1e76.

libsolidity/interface/CompilerStack.h

@@ -86,8 +86,6 @@ class DeclarationContainer;
  * Easy to use and self-contained Solidity compiler with as few header dependencies as possible.
  * It holds state and can be used to either step through the compilation stages (and abort e.g.
  * before compilation to bytecode) or run the whole compilation in one call.
- * If error recovery is active, it is possible to progress through the stages even when
- * there are errors. In any case, producing code is only possible without errors.
  */
 class CompilerStack: public langutil::CharStreamProvider
 {
@@ -101,7 +99,7 @@ public:
 		SourcesSet,
 		Parsed,
 		ParsedAndImported,
-		AnalysisPerformed,
+		AnalysisSuccessful,
 		CompilationSuccessful
 	};
 
@@ -137,10 +135,6 @@ public:
 	/// @returns the current state.
 	State state() const { return m_stackState; }
 
-	bool hasError() const { return m_hasError; }
-
-	bool compilationSuccessful() const { return m_stackState >= CompilationSuccessful; }
-
 	/// Resets the compiler to an empty state. Unless @a _keepSettings is set to true,
 	/// all settings are reset as well.
 	void reset(bool _keepSettings = false);
@@ -520,9 +514,6 @@ private:
 	bool m_parserErrorRecovery = false;
 	State m_stackState = Empty;
 	CompilationSourceType m_compilationSourceType = CompilationSourceType::Solidity;
-	/// Whether or not there has been an error during processing.
-	/// If this is true, the stack will refuse to generate code.
-	bool m_hasError = false;
 	MetadataFormat m_metadataFormat = defaultMetadataFormat();
 };